Food as Medicine: Shallot (Allium cepa var. aggregatum, Amaryllidaceae)

Overview

Shallot (Allium cepa var. aggregatum, syn. A. ascalonicum, Amaryllidaceae) is a variety of the common onion (A. cepa).1 Shallots grow natively in the mountains of central Asian countries, including Afghanistan, Tajikistan, Pakistan, and parts of Siberia and China, and they gradually spread throughout Europe as international trade expanded.2 It is a herbaceous plant with alternating foliar leaves that sheath at the base to create the superficial impression that they originate from an above-ground stem.1 Shallot bulbs, which are bunched in groups that resemble large garlic (A. sativum) bulbs, are the portion of the plant commonly used.3 While edible, the above-ground stems and leaves generally are discarded. France, the Netherlands, Great Britain, and the United States are major commercial producers of shallots, and many other countries throughout Southeast Asia and Africa also cultivate and export them.1,2

Phytochemicals and Constituents

Of all the onion varieties, shallots contain the highest amount of total flavonols, which have been shown to reduce systemic inflammation and cellular oxidation.4 Many of these bioactive components have been isolated and studied in vitro for their potential protective effects against chronic diseases such as cancer and diabetes.5 One such flavonol is quercetin, which is one of the many phenolic compounds found in many fruits and vegetables that exhibit biological activities.6 Quercetin is reportedly more bioavailable from the dry skin of shallots rather than the flesh, where it is mainly found in the form of quercetin glycosides (quercetin glycosides can be broken down in the body to produce quercetin).7 When metabolized, quercetin forms metabolites that are less biologically potent than quercetin glycosides, but these metabolites still retain some anti-inflammatory properties that have been shown to protect against inflammation-related diseases such as cardiovascular disease (CVD).5

Antioxidants are a group of bioactive compounds that, among other activities, reduce free radical damage to lipids and DNA by reactive oxygen species (ROSs). Antioxidants either accept or donate an electron to stabilize ROS and to reduce their damaging capabilities. Phenolic compounds such as flavonols, carotenoids (fat-soluble pigments that give some plants their orange, yellow, and red colors), ascorbic acid (vitamin C), thiols, and tocopherols (vitamin E) are all examples of antioxidant molecules.8

Flavonols have been widely shown to have potent antioxidant activity in vitro and in vivo. Flavonols have also been extensively studied for their actions on inhibiting the proliferation of cancer cells in vitro. The antioxidant capacity and the anti-proliferative ability of flavonols change depending on how these compounds are metabolized. When tested in liver and colon cell lines designed to mimic human metabolism, the antioxidant activity of the flavonols found in shallots was retained more than the antioxidant activity of the flavonols found in other onion varieties.8

Shallots and other Allium crops have high concentrations of organosulfides, which are sulfur-containing phytonutrients that are metabolized by the enzyme alliinase when the plant tissue is ruptured (e.g., from cooking, chewing, or crushing).9,10 These compounds give Allium plants their recognizable flavor and pungency, with different species differing in flavor and pungency due to variations in the concentrations of types of organosulfides.9 Organosulfides are highly bioavailable in animal models, preserved through metabolism, and can be detected in the blood at dose-dependent concentrations.10 As a result, their antioxidant activity is retained. In humans, their bioavailability is unknown, so further investigation is needed to determine whether biologically active concentrations of organosulfides can be achieved through traditional dietary intake or through pharmacological interventions.10

Finally, isoliquiritigenin is a flavonoid found in high concentration in shallots. Like organosulfides, isoliquiritigenin is highly bioavailable.11 Isoliquiritigenin absorption is dose-dependent and varies depending on tissue type.

Historical and Commercial Uses

There is little information regarding the historical medicinal uses of shallot, which was originally named Allium ascalonicum after its popularity in the city of Ascalon, Syria, but Allium crops generally were used to treat gastrointestinal issues and tumors and known for their anti-microbial properties.12 The Roman naturalist Pliny the Elder mentioned the shallot as one of six types of onions known to the Greeks in his 77 CE encyclopedia Naturalis Historia.1 By 1554, shallots were grown in Spain, Italy, France, and Germany and Baldassare Pisanelli, a 17th-century doctor in Italy, described the shallot as “a delicious food that stimulates the appetite when it is hot and makes tasty to drink.”4 Cultivation of shallots spread to England from France by 1663, and shallots became a common crop in the United States by 1806.1 Today, shallots are used for culinary purposes: cooked in stews and soups, diced raw in salads or to accompany meats, or pickled.1

Modern Research

There are limited data regarding the effect of shallots as a whole food on the disease, but specific phytonutrients from shallot have been isolated and studied for their activities and effects on different disease states.

Cancer Prevention

Plants in the genus Allium, including shallot, have been shown to significantly reduce the risk of gastric cancer in humans. A meta-analysis of epidemiological studies showed that the consumption of 20 grams daily of Allium vegetables (equivalent to the weight of one garlic bulb) reduced the incidence of gastric cancer in individuals when compared to those who consumed lower amounts.13 Similarly, the World Cancer Research Fund (WCRF) in conjunction with the American Institute for Cancer Research (AICR) published a comprehensive report of the existing literature on diet and cancer that found strong evidence to support shallot’s inhibiting effect on cancer cell lines.14 In addition to reducing the risk of gastric cancer, Allium vegetables were also credited with reducing the risk of all cancers.14 However, the WCRF/AICR report recommended a higher dosage of Allium vegetables (100 grams daily) to reduce the risk of gastric and other cancers than that specified by the previously mentioned meta-analysis.13,14

Individual phytonutrients present in shallots have been studied for their capabilities to inhibit the initiation, promotion, and progression of certain types of cancer.  Isoliquiritigenin, for example, has been shown to be a potent inhibitor of the metastatic potential of human prostate cancer cells.15 This essentially results in the cell’s ability to “turn off” growth in order to prevent the uncontrolled cell growth and division important for tumor survival. Isoliquiritigenin has also been shown to induce apoptosis (normal, pre-programmed cell death) via mitochondrial-mediated effects.16,17 Similar apoptotic effects were observed when hepatoma, gastric, and melanoma cancer cell lines were treated with isoliquiritigenin.16,17 In addition, treatment with isoliquiritigenin in human lung cancer cells resulted in cell cycle arrest, which inhibited cancer cell growth and proliferation.18 Studies that monitor in vivo effects of isoliquiritigenin are needed to further explore the anti-tumor potential of this compound.

Isoliquiritigenin has the potential to act as a safe alternative to commonly used chemotherapies. In a mouse study, renal carcinoma was treated with isoliquiritigenin, which suppressed pulmonary metastases without the leukocytopenia and weight loss associated with the administration of the commonly used chemotherapy drug 5-fluorouracil.19 More studies are needed to determine the dosage at which isoliquiritigenin is effective and safe in humans, but this phytochemical may offer a promising alternative to approved chemotherapies that are associated with harmful side effects.

Organosulfides also contribute to the antioxidant activity of shallots.10 These compounds have been studied in vitro for their ability to halt cell cycle progression, induce apoptosis, and inhibit angiogenesis of tumor cells.10 Similar effects have been observed in vivo, in which organosulfides have been linked to the inhibition of skin carcinogenesis and prevention of both carcinogen-induced colon cancer and carcinogen-induced esophageal tumors in rats.10 In a clinical trial involving the administration of a high dose of metabolized organosulfides (200 mg per day) over a five-year period, researchers observed a 22% lower incidence of all cancers and a 47.3% lower incidence of gastric cancer in these individuals compared to those who did not receive treatment.10 No adverse effects were observed with this high-dose treatment, highlighting the safety of these compounds. However, further research into the efficacy of these metabolites for cancer chemoprevention is needed.

Diabetes

Shallot as a whole food has been studied for its hypoglycemic activity. In a mouse study, juiced shallot bulbs were administered orally.20 The blood glucose levels of mice treated with shallot bulb juice were found to be 13.3% lower in the treatment group, compared to an increase of 1.57% in the control group and the end of the 15-day study period. Another animal study compared the glucose-lowering effects of a shallot bulb extract and the commonly prescribed blood glucose-lowering drug, metformin, in rats.21 The reduction of blood glucose observed with shallot bulb extract treatment was similar to that observed with metformin. In addition, treatment with the shallot extract significantly inhibited the metabolism of ingested carbohydrates and increased the cellular absorption of circulating blood glucose.

Another animal study compared the antioxidant and hypolipidemic properties of the shallot bulb extract and metformin in diabetic rats.22 In the group treated with the shallot bulb extract, the following increases in phase II antioxidant enzyme activity were observed compared to the control group: superoxide dismutase by 65%, glutathione peroxidase by 43%, and catalase by 55%. Metformin only slightly increased superoxide dismutase activity by 8% when compared to the control group. When comparing lipid profiles, the shallot bulb extract affected only very low-density lipoprotein (VLDL), which was reduced by 24% in comparison to the control group. Treatment with metformin was half as effective, reducing VLDL by only 12%.

Anti-Inflammatory

A high daily intake of flavonoids from fruits and vegetables is associated with an approximately 50% reduction in mortality from CVD compared to consuming low amounts.8 As quercetin is metabolized by the human body, it retains the ability to function as an anti-inflammatory agent and inhibits the expression of adhesion molecules on the surface of endothelial cells.5 (The presence of adhesion molecules on the surface of endothelial cells can contribute to vascular inflammation and the formation of atherosclerotic lesions.5) By reducing these effects and by reducing the damage caused by oxidative stress, flavonols can act as anti-inflammatory agents to further reduce the risk for inflammatory-related diseases such as certain types of cancer, diabetes, and CVD.23

Antimicrobial

Allium plants are well-known for their disease resistance, which has been attributed in part to the antimicrobial activity of saponins present within these plants.24 These same properties have also been applied to human pathogens. Exposure to antibiotic-resistant Mycobacterium tuberculosis to shallot bulb extract resulted in bacterial death.25 Organosulfides have specifically been studied for their anti-fungal properties against several genera of human pathogens including Candida, Cryptococcus, Trichophyton, Epidermophyton, and Microsporum.12 Organosulfides have also been shown to be effective against many bacteria, including Bacillus spp., Enterococcus spp., Escherichia coli, Helicobacter pylori, Salmonella Typhimurium, Staphylococcus aureus, and Vibrio cholera. Organosulfides have synergistic effects when combined with antibiotics and broad-spectrum fungicides.

Nutrient Profile26

Macronutrient Profile: (Per 1/4 cup chopped shallot [approx. 40 grams])

29 calories

1 g protein

6.72 g carbohydrate

0 g fat

Secondary Metabolites: (Per 1/4 cup chopped shallot [approx. 40 grams])

Good source of:

Vitamin B-6: 0.14 mg (7% DV)

Manganese: 0.12 mg (6% DV)

Vitamin C: 3.2 mg (5.3% DV)

Dietary Fiber: 1.3 g (5.2% DV)

Also, provides:

Potassium: 134 mg (3.8% DV)

Folate: 14 mcg (3.5% DV)

Iron: 0.5 mg (2.8% DV)

Phosphorus: 24 mg (2.4% DV)

Magnesium: 8 mg (2% DV)

Calcium: 15 mg (1.5% DV)

Thiamin: 0.02 mg (1.3% DV)

Trace amounts:

Riboflavin: 0.01 mg (0.6% DV)

Niacin: 0.08 mg (0.4% DV)

Vitamin K: 0.3 mcg (0.4% DV)

Vitamin A: 2 IU (0.04% DV)

Vitamin E: 0.02 mg (0.01% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Kumquat-Shallot Vinaigrette

Courtesy of Catherine Applegate

Ingredients:

  • 1/3 cup extra virgin olive oil
  • 1 tablespoon champagne or white wine vinegar
  • 1 tablespoon brown or Dijon mustard
  • 1 tablespoon honey
  • 1 small shallot, minced
  • 5 kumquats

Directions:

  1. Combine all ingredients except the kumquats in a jar or bowl.
  2. Grate the zest from two kumquats into the dressing. Halve and seed all kumquats, leaving the peel intact, and juice them into the dressing. Add the juiced kumquats into the jar or bowl.
  3. Mix all ingredients together with a whisk or by putting a lid on the jar and shaking it vigorously.
  4. Refrigerate in an airtight container for a few hours before use.
  5. Serve dressing over a roasted beet or fresh green salad, or use as a sauce over chicken, pork, or fish.

References

  1. Peterson J. The Allium species (onions, garlic, leeks, chives, and shallots). Staple Food Domest Plants Anim. 1987;2:249-271.
  2. Shallots over the world. Shallot.com. Available at: http://www.shallot.com/shallot-en/facts/shallots-over-the-world.aspx. Accessed January 25, 2017.
  3. Goldman IL. Onions and other Allium plants. Encycl Food Cult. 1994;(1963):8-14.
  4. Fattorusso EF, Iorizzi MAI, Lanzotti VIL, Taglialatela-Scafati O. Chemical composition of shallot (Allium ascalonicum Hort .). J Agric Food Chem. 2002;50:5686-5690.
  5. Lotito SB, Zhang WJ, Yang CS, Crozier A, Frei B. Metabolic conversion of dietary flavonoids alters their anti-inflammatory and antioxidant properties. Free Radic Biol Med. 2011;51:454-463.
  6. Bonaccorsi P, Caristi C, Gargiulli C, Leuzzi U. Flavonol glucosides in Allium species: A comparative study by means of HPLC – DAD – ESI-MS – MS. Food Chem. 2008;107:1668-1673.
  7. Wiczkowski W, Romaszko J, Bucinski A, et al. Quercetin from shallots (Allium cepa L. var. aggregatum) is more bioavailable than its glucosides. J Nutr. 2008;138:885-888.
  8. Yang J, Meyers KJ, Van Der Heide J, Liu RH. Varietal differences in phenolic content and antioxidant and antiproliferative activities of onions. J Agric Food Chem. 2004;52:6787-6793.
  9. Vazquez-Prieto MA, Miatello RM. Organosulfur compounds and cardiovascular disease. Mol Aspects Med. 2010;31(6):540-545.
  10. Powolny AA, Singh SV. Multitargeted prevention and therapy of cancer by diallyl trisulfide and related Allium vegetable-derived organosulfur compounds. Cancer Lett. 2008;269:305-314.
  11. Cuendet M, Guo J, Luo Y, et al. Cancer chemopreventive activity and metabolism of isoliquiritigenin, a compound found in licorice. Cancer Prev Res. 2010;3(2):221-233.
  12. Lanzotti V, Scala F, Bonanomi G. Compounds from Allium species with cytotoxic and antimicrobial activity. Phytochem Rev. 2014;13:769-791.
  13. Zhou Y, Zhuang WEN, Hu WEN, Liu GJ, Wu TAIX, Wu XT. Consumption of large amounts of Allium vegetables reduces the risk of gastric cancer in a meta-analysis. Gastroenterology. 2011;141:80-89.
  14. World Cancer Research Fund / American Institute for Cancer. Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective. Washington DC: AICR; 2007.
  15. Kwon GT, Cho HJ, Chung WY, Park KK, Moon A, Park JH. Isoliquiritigenin inhibits migration and invasion of prostate cancer cells: possible mediation by decreased JNK/AP-1 signaling. J Nutr Biochem. 2009;20:663-676.
  16. Jung JI, Chung E, Seon MR, et al. Isoliquiritigenin (ISL) inhibits ErbB3 signaling in prostate cancer cells. BioFactors. 2006;28:159-168.
  17. Jung JI, Lim SS, Choi HJ, et al. Isoliquiritigenin induces apoptosis by depolarizing mitochondrial membranes in prostate cancer cells. J Nutr Biochem. 2006;17:689-696.
  18. Ii T, Satomi Y, Katoh D, et al. Induction of cell cycle arrest and p21 (CIP1/WAF1) expression in human lung cancer cells by isoliquiritigenin. Cancer Lett. 2004;207:27-35.
  19. Yamazaki S, Morita T, Endo H, et al. Isoliquiritigenin suppresses pulmonary metastasis of mouse renal cell carcinoma. Cancer Lett. 2002;183:23-30.
  20. Luangpirom A, Kourchampa W, Junaimuang T, Somsapt P, Sritragool O. Effect of shallot (Allium ascalonicum L.) bulb juice on hypoglycemia and sperm quality in streptozotocin-induced diabetic mice. Int J Bioflux Soc. 2013;5(1):49-54.
  21. Moradabadi L, Kouhsari SM, Sani MF. Hypoglycemic effects of three medicinal plants in experimental diabetes: Inhibition of rat intestinal α -glucosidase and enhanced pancreatic insulin and cardiac glut-4 mRNAs expression. Iran J Pharm Res. 2013;12(3):387-397.
  22. Sani MF, Kouhsari SM, Moradabadi L. Effects of three medicinal plants extracts in experimental diabetes: Antioxidant enzymes activities and plasma lipids profiles in comparison with metformin. Iran J Pharm Res. 2012;11(3):897-903.
  23. Murthy NS, Mukherjee S, Ray G, Ray A. Dietary factors and cancer chemoprevention: An overview of obesity-related malignancies. J Postgr Med. 2009;55(1):45-55.
  24. Teshima Y, Ikeda T, Imada K, et al. Identification and biological activity of antifungal saponins from shallot (Allium cepa L. aggregatum group). J Agric Food Chem. 2013;61(31):7440-7445.
  25. Amin M, Segatoleslami S, Hashemzadeh M. Antimycobacterial activity of the partial purified extract of Allium ascalonicum. Jundishpar J Microbiol. 2009;2(4):144-147.
  26. Basic Report: 11677, Shallots, raw. United States Department of Agriculture Agricultural Research Service. Available at: https://ndb.nal.usda.gov/ndb/foods/show/3314. Accessed January 25, 2017.

Food as Medicine: Carrot (Daucus carota, Apiaceae)

History and Traditional Use

Range and Habitat

Ubiquitous at any supermarket, the common root vegetable carrot (Daucus carota, subsp. sativus) is a biennial plant that is an excellent source of vitamin A (one cup contains approximately 600% of the recommended daily value) and fiber.1 Indigenous to Europe as well as parts of Asia and northern Africa, carrots now are cultivated commonly in a wide range of environments as they can withstand frosts.2 The colorful varieties of carrots, as well as their hardiness, make them popular with home gardeners.

Phytochemicals and Constituents

Favored for their sweet flavor and versatility, carrots not only supply an impressive array of vitamins and minerals, but also contain carotenoids such as alpha- and beta-carotene, lycopene, and the flavonoid quercetin. Though the orange carrot is the most well known in modern times, carrots appear in a number of colors including white, yellow, red, and purple.3 In fact, purple was the prevailing color for carrots until about four hundred years ago, when popular theory claims that the unusual orange variety was cultivated in Holland as a sign of Dutch nationalism to honor William of Orange. The exact reason why the orange cultivar became the dominant variety is unknown, though genetic evidence suggests that orange carrots developed from yellow ones.4

The different colors of carrots reveal their various concentrations of phytochemicals.5 Carotenoids give yellow, orange, and red carrots their colors, while anthocyanins produce the deep purple variety. Orange carrots contain high quantities of beta-carotene. Yellow carrots contain low quantities of beta-carotene, but higher levels of lutein, which may protect from age-related macular degeneration and be beneficial for eyesight. Red carrots contain lycopene — a potent antioxidant with potential anti-cancer activity — in concentrations similar to that of tomatoes. Red carrots also contain moderate levels of alpha- and beta-carotene and lutein. Purple carrots contain high levels of anthocyanins, antioxidants that have anti-inflammatory and cardio-protective properties. The white variety has low levels of these phytochemicals but contains high levels of potassium.

Historical Uses

The record of the use of carrots in herbalism dates back to the 10th century, with mentions in the Old English Herbarium and the Leech Book of Bald indicating the use of the root as an emmenagogue as well as a treatment for smallpox and cough.6 Around the world, both root and seed have documented historical uses, typically to promote menstruation or as a diuretic. A different species, the wild American carrot (D. pulsillus), has an ethnobotanical history among many American native tribes as a remedy for colds, fevers, itching, and snake bites.7

Modern Research

Current research suggests that carrots may possess anti-cancer properties,8-10 as well as benefits for people with high blood pressure11 and cardiovascular disease.12 Beta-carotene is converted by the body into vitamin A and is a powerful antioxidant, protecting the body from free radicals and maintaining healthy skin and eyes.13

Consuming large amounts of beta-carotene, especially from carrots, can result in a harmless side effect called carotenemia, which temporarily yellows the skin.13 Infants, whose commercial foods often contain carrot puree as an added ingredient, are most likely to get carotenemia. The yellowing effect subsides as the body processes the excess beta-carotene.

Carrots can be enjoyed cooked or raw, as they retain their nutrients during the cooking process.14 Their sweetness adds to their versatility and supports their use in both sweet and savory dishes. A sweet-and-spicy pickle, for example, enhances the carrot’s natural flavor and a pleasing crunch.


Nutrient Profile

Macronutrient Profile: (Per 1 cup raw carrots)

52 calories
1.26 g protein
12 g carbohydrates
0.23 g fat

Secondary Metabolites: (Per 1 cup raw carrots)

Excellent source of:

Vitamin A: 34,317 IU (~686% DV)
Vitamin K: 16.1 mcg (20% DV)

Very good source of:

Vitamin C: 11.4 mg (18% DV)
Dietary Fiber: 3.7 g (14.6% DV)
Potassium: 394 mg (11.3% DV)

Good source of:

Vitamin B6: 0.2 mg (9% DV)
Manganese: 0.2 mg (8.5% DV)
Molybdenum: 6.1 mcg (8.1% DV)
Thiamin: 0.1 mg (8.0% DV)
Niacin: 1.1 mg (5.6% DV)
Phosphorus: 53.7 mg (5.4% DV)
Magnesium: 18.3 mg (4.6% DV)
Folate: 17.1 mcg (4.3% DV)

DV = Daily Value, as established by the US Food and Drug Administration, based on a 2,000-calorie diet.


Recipe: Spicy Pickled Carrots

Adapted from Alton Brown15

Ingredients:

  • 1 lb. baby carrots
  • 2 cloves of garlic, peeled and crushed
  • 1 cup of water
  • 1/2 cup of sugar
  • 1 1/2 cups apple cider vinegar
  • 1/2 teaspoon yellow mustard seeds
  • 1 1/2 teaspoons kosher salt
  • 1 teaspoon dried chili flakes
  • 2 dried red chilies

Directions:

  1. Place carrots and garlic in a 1-quart, spring-top glass jar.

  2. In a non-reactive

    sauce pan

    , bring the water, sugar, cider vinegar, mustard seeds, salt, and dried chili flakes to a boil, stirring to dissolve the sugar and salt. Boil for 4 minutes.

  3. Slowly pour the pickling liquid into the jar, covering the carrots and garlic completely. Submerge the

    chilies

    in the jar and cool before sealing.

  4. Refrigerate for two days (for a milder pickle) or a week (for a spicier pickle). These will get hotter the longer they are kept.

References

  1. Basic Report: 11124, Carrots, raw. US Department of Agriculture National Agricultural Library. Available here. Accessed November 19, 2014.
  2. Taxon: Daucus carota L. Germplasm Resources Information Network – (GRIN) [Online Database]. National Germplasm Resources Laboratory. Available here. Accessed November 19, 2014.
  3. History of the Carrot Part Three: From Medicine to Food – A.D. 200 to 1500. World Carrot Museum website. Available here. Accessed November 19, 2014.
  4. History of the Carrot Part Five: The Road to Domestication and the Colour Orange. World Carrot Museum website. Available here. Accessed November 19, 2014.
  5. Arscott SA, Tarnumihardjo SA. Carrots of many colors provide basic nutrition and bioavailable phytochemicals acting as a functional food. Comprehensive Reviews in Food Science and Food Safety. March 2010;9(2):223-239. Available here. Accessed December 3, 2014.
  6. What the Ancient Herbalists Said about Carrots. World Carrot Museum website. Available here. Accessed November 19, 2014.
  7. Moerman DE. Native American Ethnobotany. Portland, OR: Timber Press; 1998.
  8. Bhanot A, Sharma R, Noolvi M. Natural sources as potential anti-cancer agents: A review. International Journal of Phytomedicine [serial online]. April 2011;3(1):9-26.
  9. Aggarwal B, Shishodia S. Molecular targets of dietary agents for prevention and therapy of cancer. Biochemical Pharmacology [serial online]. May 14, 2006:1397, 1421.
  10. Rana Z, Malcolm R. C, Christine L. Le M. Bioactive Chemicals from Carrot (Daucus carota) Juice Extracts for the Treatment of Leukemia. Journal of Medicinal Food [serial online]. November 2011;14(11):1303-1312.
  11. Potter AS, Foroudi S, Stamatikos A, Patil BS, Deyhim F. Drinking carrot juice increases total antioxidant status and decreases lipid peroxidation in adults. Nutr J. September 24, 2011;10:96.
  12. Buijsse B, Feskens E, Kwape L, Kok F, Kromhout D. Both α- and β-Carotene, but Not Tocopherols and Vitamin C, Are Inversely Related to 15-Year Cardiovascular Mortality in Dutch Elderly Men. Journal of Nutrition [serial online]. February 2008;138(2):344-350.
  13. Vitamin Library: Beta-Carotene. Andrew Weil, MD website. Available here. Accessed November 19, 2014.
  14. Rock CL, Lovalvo JL, Emenhiser C, Ruffin MT, Flatt SW, Schwartz SJ. Bioavailability of beta-carotene is lower in raw than in processed carrots and spinach in women. J Nutr. 1998;128:913-916.
  15. Firecrackers. Food Network website. Available here. Accessed December 3, 2014.

Food as Medicine: Watermelon (Citrullus lanatus, Cucurbitaceae)

History and Traditional Use


Range and Habitat

The watermelon is the largest edible fruit grown in the United States: an annual trailing plant with fruits that can grow from 5-50 pounds and vines that can reach up to 20’ in length. Each fruit forms from a yellow flower, and the spherical or ovoid fruit is typically smooth and green or green with lighter banded stripes. The watermelon is native to the Kalahari Desert in Africa, and it thrives in well-draining, sandy soil. Currently, watermelons are cultivated all over the world, with Asia producing 60% of watermelons globally. The United States ranks fifth in global watermelon production. Forty-four states grow watermelons, including Texas, Florida, Georgia, and California, which collectively produce 2/3 of all the watermelons domestically.

Phytochemicals and Constituents

Watermelon contains an array of important vitamins and minerals including vitamin A, vitamin C, vitamin B-6, potassium, and beta-carotene. Watermelon also contains the important bioactive compounds citrulline and lycopene. Vitamin C acts as an antioxidant and anti-cancer agent. Watermelon’s vitamin C content may be linked to reducing blood pressure, as does its smaller amounts of vitamins B6 and E. The human body converts beta-carotene into vitamin A, which promotes healthy eyes, a strong immune system, and healthy skin. Vine fruits like watermelon are a good source of potassium, a crucial electrolyte for nerve and muscle function. Potassium is an essential nutrient as the body ages, as it decreases high blood pressure and reduces the risk of kidney stones, stroke, and bone density loss.

Citrulline is a precursor to the amino acid arginine and is involved in the process of removing nitrogen from the blood and eliminating it through urine. Arginine is a precursor for the synthesis of nitric oxide in the body, which is a vasodilator (blood vessel-widening agent). Conditions that benefit from vasodilation, such as cardiovascular diseases, erectile dysfunction, and headaches may benefit from increased arginine intake. Arginine also helps the body make protein, which boosts muscle growth, enhances wound healing, combats fat accumulation, and stimulates the immune system.

Though the tomato (Solanum lycopersicum) is more well-known as a source for lycopene (and in fact, its name is derived from lycopersicum), lycopene is a carotenoid found in many red foods, including watermelon, papaya (Carica papaya), pink grapefruit (Citrus x paradisi), and red carrots (Daucus carota subsp. sativus). A powerful antioxidant, lycopene may help prevent heart disease and has shown a potent ability to protect the body from “free radicals,” which may play a role in the development of heart disease, Alzheimer’s disease, and many cancers. Lycopene may also boost sperm counts and lower the risk of prostate cancer.

Historical and Commercial Uses

Though native to the African Kalahari desert, where the watermelon gourd was often used as a canteen, the cultivation of watermelon spread quickly, and other cultures adopted it as a beneficial, healing food. Ancient Egyptians used watermelon to treat reproductive problems such as erectile dysfunction and prostate inflammation. The peoples of Russia and Central Asia used watermelon as a diuretic and to cleanse the blood. In Traditional Chinese Medicine, watermelon is considered cooling and moistening, producing a diuretic effect, and commonly is used to treat thirst, edema, and inflammation of the kidney and urinary tracts.18 Because watermelon is 92% water, many traditional uses of watermelon overlap with current uses, including hydration, cleansing, and eliminating impurities. Since watermelon is digested relatively quickly, the folk traditions of the Papua New Guinea aborigines known as Onabasulu advised against eating watermelon and other juicy fruits after a heavy meal or if suffering from a stomachache.

African cuisine treats the watermelon as a vegetable and uses the entire fruit: seeds, rinds, and flesh. The seeds are eaten as snacks added to dishes or ground into flour for use in baked goods. The rind can be stir-fried, stewed, candied, pickled, or grilled. The flesh is eaten or juiced, but it can also be fermented into alcohol; in the southern part of Russia, the juice is combined with hops to make beer.

Modern Research

The traditional uses for watermelon as a medicine are beginning to gain scientific confirmation, particularly in regards to its applications against erectile dysfunction, dehydration, kidney disease, and anti-aging concerns. Watermelon’s antioxidant and nutrient content defend against many different conditions.

Current research shows that citrulline in watermelons has beneficial effects on the heart, dilating the blood vessels and improving blood flow. In one clinical study, obese participants with pre-high blood pressure or stage-one high blood pressure significantly reduced their ankle and brachial systolic blood pressure, diastolic blood pressure, mean arterial pressure, and carotid wave reflection with ingestion of citrulline from watermelons. A review of consumption of citrulline from watermelon demonstrated improvements in glycemic control and circulatory problems in diabetics, a reduction in cardiovascular risk factors, and increased levels of arginine, an essential amino acid. Because arginine is involved in maintaining the health of the reproductive, pulmonary, renal, gastrointestinal, hepatic, and immune systems, citrulline is of increasing interest in the realm of scientific study. Studies show that citrulline is more bioavailable in the body than arginine, making it a better candidate for arginine deficiency diseases such as renal carcinoma, chronic inflammatory diseases, or blood cell diseases like sickle cell anemia and malaria. Citrulline research also has shown promising results of becoming a biomarker for bowel problems of the small intestine as well as kidney failure.13

Lycopene’s powerful antioxidant properties have been shown to reduce the risks of prostate, lung, gastric, and colorectal cancers. However, due to its antioxidant effect, it seems to interfere with chemo and radiation therapy. In addition to being an antioxidant, lycopene has been shown to be heart-protective and lowers LDL cholesterol. In one study, lycopene ingestion showed a reduction in the risk of stroke, especially ischemic strokes in men. Finally, lycopene has been linked to a reduction in cardiovascular risks.

Nutrient Profile


Macronutrient Profile
(Per 1 cup diced watermelon [approx. 152 g]):

46 calories
1 g protein
11.5 g carbohydrate
0.2 g fat

Secondary Metabolites (Per 1 cup diced watermelon [approx. 152 g]):

Excellent source of:

Vitamin C: 12.3 mg (20.5% DV)
Vitamin A: 865 IU (17.3% DV)

Very good source of:

Potassium: 170 mg (4.9% DV)

Also provides:

Magnesium: 15 mg (3.8% DV)
Vitamin B-6: 0.07 mg (3.5% DV)
Thiamin: 0.05 mg (3.3% DV)
Vitamin E: 0.08 mg (3% DV)
Manganese: 0.06 mg (3% DV)
Dietary Fiber: 0.6 g (2.4% DV)
Iron: 0.4 mg (2.2% DV)
Phosphorus: 17 mg (1.7% DV)
Folate: 5 mcg (1.3% DV)
Calcium: 11 mg (1.1% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.


Recipe: Pickled Watermelon Rinds

Adapted from Bon Appétit


For an equally delicious condiment without the wait, use these ingredients to make watermelon rind chutney: increase sugar to 1 ½ cups, water to 1 cup, and finely mince the ginger. Bring all ingredients to a boil in a large pan, then simmer for 45-60 minutes until the rind is translucent and tender and the liquid reduces and thickens. Remove whole spices before serving.

Ingredients:

  • 4 lbs of watermelon
  • 1 serrano chili, thinly sliced, seeds removed if desired
  • 1-inch piece of fresh ginger, peeled and thinly sliced
  • 2-star anise pods
  • 1 tablespoon kosher salt
  • 1 teaspoon black peppercorns
  • 1 cup sugar
  • 1 cup apple cider vinegar

Directions:

  1. Using a vegetable peeler, remove the tough green outer rind from watermelon; discard.
  2. Slice watermelon into 1”-thick slices. Cut away all but 1/4” of flesh from each slice; reserve flesh for another use. Cut rind into 1” pieces for roughly 4 cups of the rind.
  3. Bring chili, ginger, star anise, salt, peppercorns, sugar, vinegar, and 1/2 cup of water to a boil in a large, non-reactive saucepan, stirring to dissolve sugar and salt.
  4. Add watermelon rind. Reduce heat and simmer until just tender, about 5 minutes. Remove from heat and let cool to room temperature, setting a small lid or plate directly on top of rind to keep submerged in brine, if needed.
  5. Transfer rind and liquid to an airtight container; cover and chill at least 12 hours.

Food as Medicine: Grapes (Vitis vinifera, Vitaceae)

History and Traditional Use

Range and Habitat

Vitis vinifera means “the vine that bears wine” and belongs to the Vitaceae family. Grapes are perennial climbers that have coiled tendrils and large leaves. They contain clusters of flowers that mature to produce small, round, and juicy berries that can be either green (“white”) or red.1 There are seed and seedless varieties, although the seeds are edible and packed with nutrition. The juice, pulp, skin, and seed of the grape can be used for various preparations.2

Grapes are a vine and must be trained to grow along a fence, wall, or arbor.3 The fruit does not ripen after harvesting; therefore, it is important to harvest well-colored and plump berries that are wrinkle-free and still firmly attached to the vine. They are best stored in the refrigerator since freezing will decrease their flavor.1,4 Pesticide use is common in vineyards, and careful washing is recommended when purchasing conventionally grown grapes.

As one of the leading commercial fruit crops in the world in terms of tons produced, grapes are cultivated all over the world in temperate regions. The top producers are Italy, France, Spain, the United States, Mexico, and Chile.1,5 Annually, worldwide grape production reaches an average of 60 million metric tons, 5.2 million of which are grown in the United States.

Phytochemicals and Constituents

Antioxidants are enzymes and nutrients that prevent oxidation, meaning they neutralize highly reactive ions or molecules known as free radicals in the human body by donating electrons or modulating enzymes that metabolize free radicals. Free radicals are produced naturally through metabolism as part of normal physiological functions (e.g., a defense mechanism against pathogens), but may be produced in excess, creating a situation where they adversely alter lipids, proteins, and DNA, and trigger a number of human diseases. Grape and grape products are good sources of beneficial antioxidant compounds.

Grapes contain phytochemicals called polyphenols. Polyphenols are the most abundant source of dietary antioxidants and are associated with numerous health benefits.2,6 The phenolic compounds are more concentrated in the skin of the berry, rather than in the flesh or seeds, and the content tends to increase as the fruit ripens. Grapes contain polyphenols from the classes of flavonoids, stilbenes, and phenolic acids. Red wine and grapes are rich in flavonoids such as anthocyanins and catechins, stilbenes such as resveratrol, and phenolic acids such as caffeic acid and coumaric acid. Red grapes have higher concentrations of these phenolic compounds than red wine grapes. Different grape varietals contain varying amounts of phenolic compounds.

Anthocyanins are flavonoids that naturally occur in the plant kingdom and give many plants their red, purple, or blue pigmentation. Vitis vinifera may contain up to 17 anthocyanin pigments, which are contained in the skins.2,7 Grapes also contain other flavonoids, including catechins, epicatechin, and proanthocyanidins. Attempts to study the benefits of individual phytochemicals in humans has been difficult since these phytochemicals are complex and often interact with one another to increase their overall benefits.

There are numerous studies using animal models in phytochemical research.8 Animal models have shown that anthocyanins protect against oxidative stress, which can be the beginning stages of many chronic conditions, such as cardiovascular disease, diabetes, and cancer.

Grape seeds are a particularly rich source of proanthocyanidins, a class of nutrients belonging to the flavonoid family. Proanthocyanidins, also known as condensed tannins, are polymers (naturally occurring large molecules) with flavan-3-ol monomers as building blocks. The term oligomeric proanthocyanidin(OPC), which also is commonly used to describe these compounds, is not well-defined and is debated among various members of the scientific community.

Grape seed extract is available as a nutritional supplement. Partially purified proanthocyanidins have been used in phytomedicinal preparations in Europe for their purported activity in decreasing the fragility and permeability of the blood vessels outside the heart and brain.9

Grapes have a high stilbene, specifically resveratrol, content. Resveratrol, which is found in the skin and seeds of red grapes as well as in red wine, is produced as the plant’s defense mechanism against environmental stressors.1,2,10,11 Resveratrol first gained attention as a possible explanation for the “French Paradox” — the observation that French people tend to have a low incidence of heart disease despite having a typically high-fat diet.1 The antioxidant activity of grapes is strongly correlated with the amount of resveratrol found in the grape.10 Studies have found resveratrol to be anti-carcinogenic, anti-inflammatory, and cardioprotective in animal models.11 However, in a human study in which healthy adults consumed resveratrol, it was determined that the compound was readily absorbed, but it metabolized quickly, leaving only trace amounts.12

In addition to their high resveratrol content, grapes are also an excellent source of vitamin K and provide moderate amounts of potassium, vitamin C, and B vitamins.

Historical and Commercial Uses

Grapes have been consumed since prehistoric times and were one of the earliest domesticated fruit crops.1,13According to ancient Mediterranean culture, the “vine sprang from the blood of humans who had fought against the gods.”14 But according to archaeological evidence, domestication took place about 5,000 years ago somewhere between the Caspian and Black Seas and spread south to modern-day Syria, Iraq, Jordan, and Egypt before moving towards Europe.5,13 After the collapse of the Roman Empire in the 5th century, when Christianity became dominant, wine was associated with the Church and the monasteries soon perfected the process of making wine.1

About 300 years ago, Spanish explorers introduced the grape to what is now the United States, and California’s temperate climate proved to be an ideal place for grape cultivation.1

The grape is, famously, the most common ingredient in wine-making. A naturally-occurring symbiotic yeast grows on the grapes, making them easier to ferment and well-suited to the wine-making process.4 Popular wine cultivars of V. vinifera include Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc, Vermentino, and Viognier.10

Wine often has been used as a medium for herbal remedies, due to the solvent nature of the alcohol. Both the Chinese and Western traditions made use of medicated wines (though ancient recipes in China, which date to the Shang Dynasty [ca 1600-1046 BCE], would have been made with rice [Oryza sativa, Poaceae] wine rather than grape wine).15 Many aperitifs and liqueurs originally were digestive aids made with wine and fortified with herbs such as wormwood (Artemisia absinthium, Asteraceae) and anise seed (Pimpinella anisum, Apiaceae).16 Medicated wines are less potent and usually require a higher dosage than tinctures made with higher-proof alcohol.

Grapes are generally sweet and are used as table grapes, juice, jam, jelly, or for wine-making.13,17 About 99% of the world’s wine comes from V. vinifera.14 Grapes can also be dried in the vineyard and turned into raisins. To accomplish this, ripe grapes are plucked from the vine and placed on paper trays for two to four weeks. Afterward, they are sent to the processing plant to be cleaned, packaged, and shipped.5

Modern Research

Grapes have been the subject of numerous studies focused on many of their bioactive compounds, including flavonoids, stilbenes, and phenolic acids. Researchers have observed antioxidant, anti-tumor, immune modulatory, anti-diabetic, anti-atherogenic, anti-infectious, and neuroprotective properties of the fruit.11 Research suggests that grape product consumption could possibly benefit those with cancer, diabetes, and cardiovascular disease, which are among the leading causes of death worldwide.18 However, more human studies are needed to support any of these purported benefits.

An in vitro study showed that antioxidants from a variety of grape product extracts performed as well as or better than BHT, tocopherol, and Trolox in radical scavenging activity, metal chelating activity, and inhibition of lipid peroxidation.7 Water and ethanol seed extracts had the highest amount of phenolic compounds of any of the extracts used in the study.

Grape seed extract (GSE), which has a growing body of study behind it, has gained attention for its possible use in lowering blood pressure and reducing the risk of heart disease, especially in pre-hypertensive populations.19 Unlike grape skins, where only red grapes contain anthocyanins, seeds from both white and red grape contain beneficial compounds. A standardized GSE made from white wine grapes recently was studied for its effects on gastrointestinal inflammation.20 While most studies focus on GSE and cardiovascular health, the preliminary results were promising enough to warrant a future human trial.

Cardiovascular Disease

Polyphenols have been found to protect the body from inflammation, which is common in people with heart disease.11 In a recent meta-analysis, the acute effects of polyphenols on the endothelium (inner lining of the blood vessels) were investigated. The analysis found that blood vessel function significantly improved in healthy adults in the initial two hours after consuming grape polyphenols.21 Another analysis found that the polyphenol content in every part of the grape — fruit, skin, and seed — had cardioprotective effects.22In animal, in vitro, and limited human trials, grapes showed beneficial actions against oxidative stress, atherosclerosis (plaque build-up in arteries), high blood pressure, and ventricular arrhythmia (irregular heartbeat).

Cancer Chemopreventive Effects

Although the causes of and treatments for cancer are complex and multifaceted, studies have been done on the antioxidant activity of polyphenols and their cancer chemopreventive effects. These antioxidants demonstrate the ability to protect the body from cancer-causing substances and to prevent tumor cell growth by protecting DNA and regulating natural cell death.8,11,23

Diabetes

In a randomized, double-blind controlled clinical study, healthy overweight/obese first-degree relatives to type 2 diabetic patients were given grape polyphenols to counteract a high-fructose diet. After nine weeks of supplementation, grape polyphenols protected against fructose-induced insulin resistance.24 In another study, diabetic patients who consumed a dealcoholized Muscadine grape wine had reduced fasting insulin levels and increased insulin resistance.25

 

Nutrient Profile26

Macronutrient Profile: (Per 150 g [approx. 1 cup] grapes)

 

104 calories

1.1 g protein

27.3 g carbohydrate

0.2 g fat

 

Secondary Metabolites: (Per 150 g [approx. 1 cup] grapes)

 

Excellent source of:

Vitamin K: 22 mcg (27.5% DV)

 

Good source of:

Potassium: 288 mg (8.2% DV)

Vitamin C: 4.8 mg (8% DV)

Thiamin: 0.1 mg (6.7% DV)

Riboflavin: 0.1 mg (5.9% DV)

Dietary Fiber: 1.4 g (5.6% DV)

Manganese: 0.1 mg (5.5% DV)

Vitamin B6: 0.1 mg (5% DV)

 

Also provides:

Phosphorus: 30 mg (3% DV)

Magnesium: 11 mg (2.8% DV)

Iron: 0.5 mg (2.8% DV)

Vitamin A: 100 IU (2% DV)

Niacin: 0.3 mg (1.5% DV)

Vitamin E: 0.3 mg (1.5% DV)

 

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.

 

Recipe: Rosemary-Roasted Grapes and Cashew Cheese Crostini

 

Ingredients:

  • 1 cup raw cashews
  • 1-2 cloves of garlic, minced
  • 1/4 cup water
  • 1/4 cup freshly-squeezed lemon juice, divided
  • 1/2 teaspoon kosher or fine sea salt
  • 1 pound seedless red grapes, washed and removed from stem
  • 3 tablespoons olive oil, plus more for garnish
  • 1 tablespoon fresh rosemary leaves, minced
  • Salt and pepper to taste
  • 1 small baguette or other loaf, sliced diagonally in 1/4 inch thick slices

Directions:

  1. Soak cashews in enough water to cover by an inch for at least 4 hours. Drain.

  2. Make cashew “cheese” by placing soaked cashews, garlic, water, 2 tablespoons of lemon juice, and salt into a food processor and blend until smooth.

  3. Heat oven to 400°F. In a baking dish, mix grapes, olive oil, remaining lemon juice, rosemary, salt, and pepper. Place on center rack and roast 10-12 minutes or until skins are soft. Remove and set aside.

  4. Move the oven rack to the top setting and increase the heat to broil. Arrange bread slices in a single layer on a baking sheet and place in oven to toast for 1-3 minutes, monitoring carefully to prevent burning.

  5. Assemble crostini by spreading each toast with a layer of cashew cheese and topping with the grape mixture. Sprinkle with salt and drizzle with olive oil. Serve warm.

References

  1. Murray MT, Pizzorno J, Pizzorno L. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005.
  2. Yang J, Xiao YY. Grape phytochemicals and associated health benefits. Critical Reviews in Food Science and Nutrition. 2013;53:1202-1225.
  3. Damrosch B. Grapes. In: The Garden Primer: Second Edition. New York, NY: Workman Publishing; 2008:353-359.
  4. Wood R. The New Whole Foods Encyclopedia: A Comprehensive Resource for Healthy Eating. New York, NY: Penguin Books; 1999.
  5. Ensminger AH, Ensminger ME, Konlande JE. The Concise Encyclopedia of Foods & Nutrition. Boca Raton, FL: CRC Press; 1995.
  1. Tiwari B, Brunton NP, Brennan CS. Handbook of Plant Food Phytochemicals. London, UK: John Wiley & Sons, Ltd; 2013.
  1. Keser S, Celik S, and Turkoglu S. Total phenolic contents and free-radical scavenging activities of grape (Vitis vinifera L.) and grape products. International Journal of Food Sciences and Nutrition. 2013;64(2):210-216.
  1. Lila MA. Anthocyanins and human health: An in vitro investigative approach. J Biomed Biotechnol.2004;2004(5):306-313.
  1. Yamakoshi J, Saito M, Kataoka S, Kikuchi M. Safety evaluation of a proanthocyanidin-rich extract from grape seeds. Food and Chemical Toxicology. 2002;40:599-607.
  1. Burin VM, Ferreira-Lima NE, Panceri CP, Bordignon-Luiz MT. Bioactive compounds and antioxidant activity of Vitis vinifera and Vitis labrusca grapes: Evaluation of different extraction methods. Microchemical Journal. 2014;114:155-163.
  1. Yadav M, Jain S, Bhardwaj A, et al. Biological and medicinal properties of grapes and their bioactive constituents: An update. Journal of Medicinal Food. 2009;12(3):473-484.
  1. Walle T, Hsieh F, DeLegge MH, Oatis JE, Walle K. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metabolism and Disposition. 2004;32(12):1377-1382.
  1. Myles S, Boyko AR, Owens CL, et al. Genetic structure and domestication history of the grape. Proceedings of the National Academy of Science of the United States of America. 2011;108(9):3530-3535.
  1. McGovern PE. Ancient Wine: The Search for the Origins of Viniculture. Princeton, NJ: Princeton University Press; 2007.
  1. Chan K, Cheung L. Interactions Between Chinese Herbal Medicinal Products and Orthodox Drugs. Boca Raton, FL: CRC Press; 2000.
  1. Hoffmann D. The Herbal Handbook: A User’s Guide to Medical Herbalism. Rochester, VT: Inner Traditions; 1998.
  1. Onstad D. Whole Foods Companion: A Guide for Adventurous Cooks, Curious Shoppers, and Lovers of Natural Foods. White River Junction, VT: Chelsea Green Publishing; 2004.
  1. The top 10 causes of death – fact sheet no. 310. World Health Organization website. May 2014. Available here. Accessed November 23, 2015.
  1. Park E, Edirisinghe I, Choy YY, Waterhouse A, Burton-Freeman B. Effects of grape seed extract beverage on blood pressure and metabolic indices in individuals with pre-hypertension: a randomized, double-blinded, two-arm, parallel, placebo-controlled trial. Br J Nutr. 2015;16:1-13.
  1. Starling S. White wine extract shows gastro benefits in vitro. Clinics planned for 2016. NutraIngredients-USA website. November 12, 2015. Available here. Accessed November 19, 2015.
  1. Li SH, Tian HB, Zhao HJ, Chen LH, Cui LQ. The acute effects of grape polyphenols supplementation on endothelial function in adults. PLOS ONE. 2013;8(7):e69818.
  1. Leifert WR, Abeywardena MY. Cardioprotective actions of grape polyphenols. Nutrition Research. 2008;28:729-737.
  1. Waffo-Téguo P, Hawthorne ME, Cuendet M, et al. Potential cancer chemopreventive activities of wine stilbenoids and flavans extracted from grape (Vitis vinifera) cell cultures. Nutrition and Cancer. 2001;40(2):173-179.
  1. Hokayem M. Grape polyphenols prevent fructose-induced oxidative stress and insulin resistance in first-degree relatives of type 2 diabetic patients. Diabetes Care. 2013;36:1455-1461.
  1. Banini AE, Boyd LG, Allen JG, Allen HG, Sauls DL. Muscadine grape products intake, diet and blood constituents of non-diabetic and type 2 diabetic subjects. Nutrition. 2006;22:1137-45.
  2. Basic Report: 09132, Grapes, red or green (European type, such as Thompson seedless), raw. United States Department of Agriculture, Agricultural Research Service. Available here. Accessed November 19, 2015.

Food as Medicine: Mango (Mangifera indica, Anacardiaceae)

History and Traditional Use

Range and Habitat

Mangifera indica (Anacardiaceae) is a tropical tree that grows from 33 feet to 131 feet in height and produces large, oval-shaped fruits that are red and gold when ripe, though some cultivars are green or yellow.1 The smooth-edged leaves of the mango tree are reddish when young, becoming dark green and shiny as they mature. The tree produces small pinkish-white flowers that precede the fruit.2,3 The mango fruit is a drupe, or stone fruit, containing a large single seed surrounded by fleshy pulp and a thin, leathery skin.4 The mango tree begins to bear fruit four to six years after planting and continues to produce fruit for about 40 years.3,4 Trees older than 10 years tend toward alternate or biennial bearing, producing fruit every other year.5

While the most commonly used part of the plant is the fruit, the mango tree has a variety of traditional uses that make use of the roots, peel, stem bark, leaves, flowers, and seed kernels. These parts typically contain greater amounts of bioactive compounds, including mangiferin, than the fruit.4 Belonging to the same plant family as the cashew (Anacardium occidentale) and pistachio (Pistacia vera), the mango is native to India and Burma, and has been cultivated since 2000 BCE.2 The mango was introduced to Africa about 1,000 years ago and to tropical America in the 19th century.1,2 Wild fruits have a minimal resemblance to the cultivated mangos, having a much smaller size and unpleasant turpentine-like taste. Currently, mangos are grown in tropical and warm temperate climates.3 India remains the largest producer, growing 65% of the world’s mango crop.5

Phytochemicals and Constituents

The macro- and micronutrient composition and bioactive compounds present in M. indica contribute to its many health benefits. Mango fruits are a rich source of vitamins A, B and C. Mangos are also a good source of both soluble and insoluble fiber.3 Soluble fiber can help prevent cardiovascular disease and improve gastrointestinal health.

Mango is a source of many pharmacologically and medically important chemicals, including mangiferin, mangiferonic acid, hydroxy mangiferin, flavonoids, phenolic acids, and carotenes.6 Different parts of the plant have different chemical compositions. The bark, for example, contains catechins, amino acids, and phenolic and triterpenoid compounds.7,8 Due to these constituents, mango bark extract has shown antioxidant, immune system-enhancing, anti-inflammatory, antibacterial, antiviral, and antifungal activities, which correspond to many of mango’s traditional medicinal uses.7 The xanthone mangiferin is found in many different plants across the Anacardiaceae family and shows promising results in the areas of antitumor, anti-diabetic, and anti-microbial actions.

The health benefits of the fruit pulp are due to its high concentration of antioxidant nutrients and phytochemicals, such as carotenoids. Carotenoids play an important role in protective health mechanisms against some forms of cancer, cardiovascular disease, and macular degeneration, as well as improving immune health.9 Specifically, mangos are high in beta-carotene, a precursor of vitamin A. Mango also contains smaller amounts of lutein and zeaxanthin, two carotenoids important for maintaining eye health and preventing macular degeneration. These phytochemicals are antioxidants, meaning that they slow or prevent the oxidative process, thereby preventing or repairing damage to cells in the body.10

The polyphenols that have been identified in the mango fruit include gallic acid, gallotannins, quercetin, isoquercetin, mangiferin, ellagic acid, and beta-glucogallin. These polyphenols have powerful antioxidant activity as well as other potentially therapeutic effects. Gallic acid, for example, is known to have anti-inflammatory and antitumor activities, while ellagic acid has been found to exhibit antimutagenic, antiviral, and antitumor effects.4

The most biologically active compound that has been studied in the mango tree is mangiferin. Mangiferin is synthesized by the plant as a chemical defense compound.6,11 Plant parts that contain the highest amounts of mangiferin include the leaves, stem bark, heartwood, and roots. Currently, researchers are investigating potential methods of processing mango bark and peel into a palatable ingredient or food additive. Magneferin (not to be confused with the previously mentioned mangiferin) is one of a number of enzymes present in mangos that improves digestion. Others include catechol oxidase and lactase.3

Historical and Commercial Uses

Mangiferaindicia has been used in Ayurveda, India’s primary system of traditional medicine, for more than 4,000 years. The mango was thought to have aphrodisiacal properties and is still viewed as sacred today.3A variety of the plant’s parts are used as a paste or powder for cleaning the teeth, and the juice of the mango is considered a restorative tonic, as well as a treatment for heat stroke.6 Numerous parts of the mango tree are used in Ayurvedic medicine as an antiseptic, an astringent to tone lax tissues, a laxative, a diuretic, and to increase sweating, promote digestion, and expel parasitic worms or other internal parasites.12 The seeds have been used as an astringent and as a treatment for asthma. Fumes from the burning leaves are used as an inhalant to relieve hiccups and sore throats.6 The bark is used as an astringent in diphtheria and rheumatism (disorders of the joints and connective tissues), and the gum was used in dressings for cracked feet and for scabies (an infestation of the skin by the human itch mite [Sarcoptes scabiei var. hominis]).

Current Ayurvedic practices use various parts of the mango for different ailments. For diarrhea, mango leaves are pounded together and taken with rice water.13 For nosebleeds, the juice of the mango seed is placed into the nostrils. For an enlarged spleen, ripe mango juice is consumed with honey. To treat gonorrhea, mango bark is pounded and added to milk and sugar. In some tropical countries, mango is actually used as meat tenderizer, due to the power of the proteolytic enzymes that break down proteins.3In traditional ethnoveterinary medicine, all parts of the mango are used to treat abscesses, broken horns, rabid dog bites, tumors, snakebites, stings, heat stroke, miscarriage, bacterial illness, blisters and wounds in the mouth, inflammation of the inner ear, colic, diarrhea, liver disorders, excessive urination, tetanus, and asthma.14

Among the Tikunas, an indigenous people of Brazil, Colombia, and Peru, a mango leaf decoction was used as a contraceptive and abortifacient. Reportedly, taking a cupful on two successive days during menstruation acted as a contraceptive, and taking it for three days caused abortion.11,15

Mango fruit is processed at two stages of maturity. Green fruit is used to make chutney, pickles, curries, and dehydrated products like dried mango, amchoor (raw mango powder), and panna (green mango beverage). Ripe fruit is processed into canned and frozen slices, pulp, concentrate, juices, nectar, jam, purée, cereal flakes, toffee, and various dried products.4

Modern Research

Studies indicate that M. indica possesses myriad therapeutic properties, including antidiabetic, antioxidant, antiviral, cardiotonic, hypotensive, and anti-inflammatory.6 Each of the mango’s parts — fruit, pulp, peel, seed, leaves, flowers, and bark — can be used therapeutically.

A 2000 study found that mango stem bark extract showed a powerful scavenging activity of hydroxyl radicals and acted as a chelator of iron.6 Although iron is an essential mineral, it is toxic in excessive amounts. Iron chelators could be an important approach to lessen iron-induced oxidative damage and prevent iron accumulation in diseases in which accumulation is prevalent, such as hemochromatosis, a metabolic disorder in which the body absorbs too much iron, and thalassemia, a rare, inherited blood disorder caused by a lack of hemoglobin, which results in fewer healthy red blood cells.4 This same study found a significant inhibitory effect on the degradation of brain cell membranes in an animal model, and prevented DNA damage caused by some chemotherapy treatments.6,16

Polyphenolic compounds and related bioactivity are higher in the mango peel than the fruit, and higher still in the leaves and stem bark.4 The bark is one of the main parts of the tree used for medicinal purposes. A standardized aqueous extract of M. indica stem bark called Vimang (LABIOFAM Entrepreneurial Group; La Habana, Cuba) has been developed in Cuba. This extract has shown antioxidant, anti-inflammatory, and immunomodulatory properties and has been used in many countries for the treatment of heavy menstrual bleeding, diarrhea, syphilis, diabetes, scabies, cutaneous infections, and anemia.4,7

Much of the current research looks at extracts of mango bark or seed. There is a limited amount of literature that looks into the consumption of the mango fruit itself. However, a 2011 study looked at the consumption of freeze-dried mango fruit and its effects on weight loss and glucose tolerance, compared to hypolipidemic and hypoglycemic drugs, in mice fed a high-fat diet.17 In the study, consumption of freeze-dried mango prevented the increase in fat mass and the percentage of body fat. Compared with controls, mice given the freeze-dried mango had improved glucose tolerance and lowered insulin resistance.

Functional and medicinal properties of the non-fruit portions of the mango provide promising data for future uses of the plant, and may allow for less waste of the non-edible parts of the mango. The mango peel, for example, constitutes about 15-20% of the mango fruit and typically is discarded prior to consuming the fruit. In commercial processing, the discarded peels become a wasteful by-product.18 A 2015 study conducted chemical analysis and determination of the bioactive compounds in a flour made from green mango peel.19 The mango peel flour had 54 g of total dietary fiber per 100 g of dry sample, compared to 1.8 g of total dietary fiber in wheat flour. The mango peel flour also contained 21.7 mg/g of total phenolic contents and 22.4 mg/g of total flavonoid contents.

The results of this study suggest that the mango peel flour exhibited functional properties similar to wheat flour, and could serve as an acceptable substitute in baked goods and other flour-containing foods. Dietary fiber in mango peel has been shown as a favorable source of high-quality polysaccharides due to its high starch, cellulose, hemicellulose, lignin, and pectin content combined with its low fat content.18 In vitrostarch studies suggest low glycemic responses from mango peel fiber, which suggests potential use for diabetic individuals.

Mango kernel oil has recently attracted attention due to its unsaturated fatty acid composition.18 Mango kernel oil has been widely researched for its function as an antioxidant and antimicrobial agent due to its high polyphenolic content.4 The major phenolic compounds in mango seed kernels are (in order of decreasing concentration): tannins, vanillin, coumarin, cinnamic acid, ferulic acid, caffeic acid, gallic acid, and mangiferin, all providing antioxidant protection.

Health Considerations

Possibly explained by its distant relation to poison sumac (Toxicodendron vernix, Anacardiaceae) and poison ivy (T. radicans), mango peel may be irritating to the skin,3 particularly to people who are highly sensitive to these plants. This is due to the presence of alk(en)ylresorcinols, a mixture of substances that can cause contact dermatitis to those who are allergic or sensitive to it.20 Alk(en)ylresorcinol is similar to urushiol, the toxic resin that causes an itchy rash in those who come into contact with poison ivy. These allergens are more prevalent in the peel than the flesh. In one study, four patients developed hives and eczematous rash after exposure to mangos or mango trees. Children and other persons with food allergies should take caution when handling and consuming mango. Although allergy to mango is infrequent, mango has been identified as an allergy-provoking food in some individuals with other food allergies.


Nutrient Profile21

Macronutrient Profile: (Per 1 cup mango fruit)

99 calories
1.35 g protein
24.7 g carbohydrate
0.63 g fat

Secondary Metabolites: (Per 1 cup mango fruit)

Excellent source of:
Vitamin C: 60.1 mg (100.2% DV)
Vitamin A: 1,785 IU (35.7% DV)

Very good source of:
Folate: 71 mcg (17.75% DV)
Dietary Fiber: 2.6 g (10.4% DV)
Vitamin B6: 0.2 mg (10% DV)

Good source of:
Vitamin K: 6.9 mcg (8.63% DV)
Potassium: 277 mg (7.9% DV)
Vitamin E: 1.48 mg (7.33% DV)
Niacin: 1.1 mg (5.5% DV)

Also provides:
Magnesium: 16 mg (4% DV)
Riboflavin: 0.06 mg (3.53% DV)
Thiamin: 0.05 mg (3.33% DV)
Phosphorus: 23 mg (2.3% DV)
Calcium: 18 mg (1.8% DV)
Iron: 0.26 mg (1.44% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.

Recipe: Mango and Watermelon Salad

Adapted from Mango.org22

Ingredients:

  • 2 large, ripe mangos, peeled, pitted, and diced
  • 1 cup watermelon, diced
  • 1/4 cup red onion, finely diced
  • 1 jalapeño pepper, stemmed, seeded, and finely diced
  • 12 cherry tomatoes, cut in half
  • 1 cup fresh arugula, washed and dried
  • 1 clove garlic, minced
  • 2 tablespoons fresh lemon juice
  • 1 tablespoon extra-virgin olive oil
  • 2 teaspoons honey
  • 1/2 teaspoon kosher salt
  • 3 tablespoons cilantro, chopped

Directions:

  1. Combine mango, watermelon, onion, pepper, tomato, and arugula in a large bowl. Toss to combine.

  2. Whisk together remaining ingredients and taste, adjusting seasoning if necessary. Drizzle dressing over the salad, toss to

    combine,

    and serve.

References

  1. Van Wyk B-E. Food Plants of the World. Portland, OR: Timber Press; 2006.
  2. The National Geographic Society. Edible: An Illustrated Guide to the World’s Food Plants. Washington, DC: National Geographic Society; 2008.
  3. Murray M, Pizzorno J, Pizzorno L. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005.
  4. Masibo M, He Q. Mango bioactive compounds and related nutraceutical properties: A review. Food Rev Int. 2009;25:346-370.
  5. Morton JF. Mango. In: Morton JF. Fruits of Warm Climates. Miami, FL: J.F. Morton; 1987:221-239.
  6. Shah KA, Patel MB, Patel RJ, Parmar PK. Mangifera indica (Mango). Pharmacogn Rev. 2010;4(7):42-48.
  7. Wauthoz N, Balde A, Balde ES, Damme MV, Duez P. Ethnopharmacology of Mangifera indica L. bark and pharmacological studies of its main c-glucosylxanthone, mangiferin. Int J Biomed Pharma Sci. 2007;1(2):112-119.
  8. Hamid K, Algahtani A, Kim MS, et al. Tetracyclic triterpenoids in herbal medicines and their activities in diabetes and its complications. Curr Top Med Chem. 2015;15(23):2406-2430.
  9. Hewavitharana AK, Tan ZW, Shimada R, Shaw PN, Flanagan BM. Between fruit variability of the bioactive compounds, B-carotene and mangiferin, in mango. Nutrition and Dietetics. 2013;70:158-163.
  10. Johnson EJ. The role of carotenoids in human health. Nutr Clin Care. 2002;5(2):56-65.
  11. Schultes RE, Raffauf RF. The Healing Forest: Medicinal and Toxic Plants of the Northwest Amazonia.Portland, OR: Dioscorides Press; 1990.
  12. Johnson EJ. The role of carotenoids in human health. Nutr Clin Care. 2002;5(2):56-65.
  13. Amra (Mangifera indica) National R&D Facility for Rasayana website. Available here. Accessed May 19, 2016.
  14. Williamson EM. Major Herbs of Ayurveda. London, UK: Elsevier Science Limited; 2002.
  15. Duke JA, Vasquez R. Amazonian Ethnobotanical Dictionary. Boca Raton, FL: CRC Press; 1994.
  16. Martinez G, Delgado R, Perez G, Garrido G, Nunez Selles AJ, Leon OS. Evaluation of the in-vitroantioxidant activity of Mangifera indica L: extract (Vimang). Phytother Res. 2000;14:424–7.
  17. Lucas EA, Li W, Peterson SK, et.al. Mango modulates body fat and plasma glucose and lipids in mice fed a high-fat diet. Brit J Nutr. 2011;106:1495-1505.
  18. Tiwari BK, Brunton NP, Brennan CS. Handbook of Plant Food Phytochemicals: Sources, Stability and Extraction. West Sussex, UK: John Wiley & Sons, Ltd; 2013.
  19. Abidin NSA, Mohamad SN, Jaafar MN. Chemical composition, antioxidant activity and functional properties of mango (Mangifera indica L. var Perlis Sunshine) peel flour. Appl Mech Mater. 2015(754-755):1065-1070.
  20. Knödler M, Reisenhauer K, Schieber A, Carle R. Quantitative determination of allergenic 5-Alk(en)ylresorcinols in mango (Mangifera indica L.) peel, pulp, and fruit products by high-performance liquid chromatography. J Agric Food Chem. 2009;57:3639-3644.
  21. Basic Report, 09176, Mangos, raw. Agricultural Research Service, USDA website. Available here. Accessed May 19, 2016.
  22. National Mango Board. Mango and watermelon salad. Mango.org website. Available here. Accessed May 18, 2016.

Food as Medicine Ginger (Zingiber officinale, Zingiberaceae)

History and Traditional Use
Range and Habitat

Ginger (Zingiber officinale) is a tropical perennial herb native to Southeast Asia and widely cultivated in China, India, Nigeria, Australia, Jamaica, and Haiti.1 Its subterranean stem, known as a rhizome, is the edible and medicinal portion of the plant.2 Gingerroot is characterized by its knotted, beige exterior and its yellow interior. The herb features thick, protruding, reed-like3 stems and lanceolate leaves arranged in two vertical columns on opposite sides of the stem.4 Seasonally unfurling from ginger’s leaves are dense, ovoid-shaped flower structures that produce yellow-green flowers with a deep purple, yellow-marked lip.3Ginger plants can have an indefinite spread in tropical climates, though it is susceptible to pests and disease.5 The flavor of ginger is described as sweet and peppery with a prominent spicy aroma due to the presence of gingerols and ketones.6

Phytochemicals and Constituents

Thus far, researchers have identified 115 chemical components in a variety of dried and fresh ginger types.6 The most important phenolic elements of the ginger root are gingerols and their ginger-related composites — paradols, zingerone, and shogaols.6,7 Gingerols are the most abundant constituents of fresh ginger6; the three other phenolic compounds are not as plentiful. When gingerols are cooked or dried, they transform into various bioactive compounds,6 many of which have beneficial antioxidant, anti-inflammatory, and anticarcinogenic properties.7 Research suggests that the optimal dosage of ginger ranges from 250 mg to 4.8 g per day of fresh or dried rhizomes.6,8 Other dosages for ginger intake vary depending on the form in which they are consumed and the purpose for which they are intended.8

Historical and Commercial Uses

In India, ginger has been used as a flavoring agent in food and beverage preparations as well as in traditional Ayurveda medicinal practices.4 Historically, it was regarded as the mahaoushadha (“the great medicine”) among ancient Indians.9 Fresh and dried ginger is used commonly in Ayurvedic medicine for the treatment of ailments such as indigestion, fever, and digestive disorders.8 Fresh ginger is thought to be beneficial in reducing nausea and vomiting due to the presence of shogaol, and dried ginger has been shown to alleviate chronic respiratory conditions.10 In addition, gingerol, the most predominate pungent bioactive compound of ginger, has been reported to stimulate digestive enzymes to help improve gastrointestinally (GI) issues.

In Traditional Chinese Medicine, fresh ginger root (sheng jiang) is considered warm and pungent and recognized for dispersing cold within the stomach, which contributes to the treatment of nausea and vomiting.11 It also is acknowledged as an expeller of exterior cold, quelling inflammation of the stomach and infections related to the cold and flu. Dry ginger (gan jiang) is considered to be more hot and pungent than fresh ginger, and it is responsible for dispersing cold in the spleen region, thereby alleviating ailments such as diarrhea and poor appetite. Quick-fried ginger (pao jiang) is warm and bitter and used to treat symptoms associated with conditions such as dysmenorrhea and diarrhea. Asian cuisine features ginger in a number of dishes for flavoring, including soups, curries, rice dishes, stir-fries, and sauces.12

It is believed that both the Chinese and Indians have used ginger root for medicinal purposes for more than 5,000 years; however, the exact origin is unknown.6 Highly prized for its medicinal properties, ginger was a popular trading commodity exported to the Roman Empire more than 2,000 years ago from India. (Anecdotally, Queen Elizabeth I of England is credited with the creation of the gingerbread man, which evolved into a popular treat consumed during the Christmas holidays.)

Ginger is used commercially in a variety of forms, including, but not limited to, fresh, dried, and candied.6The age of the ginger plant determines its culinary and medicinal use. Young ginger root harvested at five months has not matured and typically has a mild flavor, suitable to be used fresh. At nine months, ginger characteristically has a thick skin and pungent root, from which the volatile oils can be extracted. This material also is used in dried or ground form as a spice and in commercial baking products. Further, ginger is added as a flavoring to a number of different beverages such as ginger ale, ginger beer, and ginger wine.12

Modern Research

A considerable amount of research demonstrates and supports the significant health benefits of ginger. The majority of clinical evidence for ginger’s medicinal properties is related to nausea caused by pregnancy or chemotherapy.13

Three clinical studies have explored the effects of ginger in reducing chemotherapy-induced nausea in young adults and children.14-16 The results from these studies indicated that ginger is effective in decreasing chemotherapy-induced nausea and vomiting. More specifically, one trial indicated that supplementing with ginger (0.5 g to 1.0 g liquid ginger root extract) reduces nausea.16 In a separate study, researchers observed reductions in the prevalence of nausea in patients with breast cancer when 1.5 g powdered dried ginger root was added to an antiemetic therapy following chemotherapy.14

Another clinical study observed the effects of powdered ginger in patients with intra- and postoperative nausea accompanying Cesarean sections.17 The results indicated that episodes of intraoperative nausea were reduced when ginger was administered orally. However, ginger did not have an effect on the overall incidence of intraoperative nausea and vomiting.

Ginger has been explored as a possible treatment for other GI issues such as dyspepsia, gastric emptying, and irritable bowel syndrome (IBS).18-20 The authors of one clinical study tested the effects of ginger on functional dyspepsia and gastric motility.18 The results indicated that ginger increased gastric emptying more rapidly than the placebo; however, ginger did not influence any GI symptoms. Researchers of a related clinical trial examined ginger’s effects on IBS over a period of 28 days.20 The results indicated that the group taking 1 g of ginger had a 26.4% reduction in symptoms.

Studies have shown that ginger may be beneficial for non-GI-related conditions as well. In two separate clinical studies, researchers explored ginger’s mitigating impact on dysmenorrhea.  The first study was conducted for a period of three days based on reports of pain experienced during the first two days of menstruation each month.21 The results suggested that ginger had more of an impact on dysmenorrhea symptoms compared to muscle-relaxation exercises. A similar clinical study found that at the end of the study period, 82.85% of the participants in the experimental group reported symptom improvement compared to 47.05% of the participants in the placebo group.22

Three clinical studies have examined the effects of ginger in the treatment of colorectal cancer.7,23,24 As noted, the bioactive compounds of ginger contain antioxidant, anti-inflammatory, and anticarcinogenic properties, which can interfere with pathways responsible for cancer development.7 The results of all three studies demonstrated that an intake of 2 g of ginger root was able to reduce proliferation in the colorectal epithelium. Further, one trial illustrated that ginger simultaneously increased apoptosis (normal, programmed cell death) and differentiation.7 Ginger also exhibited an anti-inflammatory effect in individuals of normal risk and lowered COX-1 in individuals at higher risk.23,24

Other clinical studies have explored the effects of ginger in relation to muscle pain, respiratory distress syndrome, chronic lower-back pain, satiety, migraines, osteoarthritis, and type 2 diabetes.25-32

Nutrient Profile33

Macronutrient Profile: (Per 1 tablespoon [6 g] raw ginger)

5 calories
0.11 g protein
1.07 g carbohydrate
0.04 g fat

Secondary Metabolites: (Per 1 tablespoon [6 g] raw ginger)

Good source of:

Magnesium: 3 mg (0.75% DV)
Potassium: 25 mg (0.7% DV)
Vitamin B6: 0.01 mg (0.5% DV)
Vitamin C: 0.3 mg (0.5% DV)
Dietary Fiber: 0.1 g (0.4% DV)
Folate: 1 mcg (0.25% DV)
Niacin: 0.05 mg (0.25% DV)
Phosphorus: 2 mg (0.2% DV)
Calcium: 1 mg (0.1% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.

Recipe: Candied Ginger

Ingredients:

  • 1 cup fresh ginger root
  •  3 cups water
  • 3 cups granulated sugar, plus additional for coating

Directions:

  1. Spray a cooling rack with nonstick spray and set it in a sheet pan lined with wax paper.

  2. Peel and thinly slice the ginger root.

  3. Bring sugar and water to a boil in a saucepan. When the sugar is dissolved, add the ginger and simmer for 30 to 45 minutes, until ginger is tender.

  4. Drain the ginger and reserve the liquid for another use. (The reserved liquid can be further reduced to make ginger syrup or added to drinks.) Spread the ginger on the cooling rack in a single layer and dry for 30 minutes.

  5. Once dry, toss ginger slices with additional sugar to coat. Store in an airtight container.

References

  1. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Austin, TX: American Botanical Council and Newton, MA: Integrative Medicine Communications; 2000.
  2. Webb GP. Dietary Supplements and Functional Foods. West Sussex, UK: Blackwell Publishing; 2011.
  3. Bown D. The Herb Society of America New Encyclopedia of Herbs and Their Uses. London, UK: Dorling Kindersley Ltd.; 2001.
  4. Ginger. University of Maryland Medical Center website. Available here. Accessed February 23, 2015.
  5. Ginger Root Production in Hawaii. Hawaii Cooperative Extension Service website. Available here. Accessed February 23, 2015.
  6. Bode AM, Dong Z. Herbal Medicine: Biomolecular and Clinical Aspects. Boca Raton, FL: CRC Press; 2011.
  7. Citronberg J, Bostick R, Ahearn T, et al. Effects of ginger supplementation on cell-cycle biomarkers in the normal-appearing colonic mucosa of patients at increased risk for colorectal cancer: results from a pilot, randomized, and controlled trial. Cancer Prev Res. 2013;6(4):271-281.
  8. Blumenthal M, Hall T, Goldberg A, Kunz T, Dinda K, Brinckmann J, et al, eds. The ABC Clinical Guide to Herbs. Austin, TX: American Botanical Council; 2003.
  9. Ravindran PN, Babu KN. Ginger: the Genus Zingiber. Boca Raton, FL: CRC Press; 2005.
  10. Ginger – Ayurveda “Root” to Good Health. Kerala – Home of Ayurveda website. Available here. Accessed March 4, 2015.
  11. Yang Y. Chinese Herbal Medicine Comparisons and Characteristics. London, UK: Churchill Livingston; 2002.
  12. Van Wyk BE. Food Plants of the World. Portland, OR: Timber Press; 2006.
  13. Weimer K, Schulte J, Maichle A, et al. Effects of ginger and expectations on symptoms of nausea in a balanced placebo design. PLoS One. 2012;7(11):e49031.
  14. Panahi Y, Saadat A, Sahebkar A, Hashemian F, Taghikhani M, Abolhasani E. Effect of ginger on acute and delayed chemotherapy-induced nausea and vomiting: a pilot, randomized, open-label clinical trial. Integr Cancer Ther. 2012;11(3):204-211.
  15. Pillai AK, Sharma KK, Gupta YK, Bakhshi S. Anti-emetic effect of ginger powder versus placebo as an add-on therapy in children and young adults receiving high emetogenic chemotherapy. Pediatr Blood Cancer. 2011;56(2):234-238.
  16. Ryan JL, Heckler CE, Roscoe J, et al. Ginger (Zingiber officinale) reduces acute chemotherapy-induced nausea: a URCC CCOP study of 576 patients. Support Care Cancer. 2012;20(7):1479-1489.
  17. Kalava A, Darji SJ, Kalstein A, Yarmush JM, SchianodiCola J, Weinberg J. Efficacy of ginger on intraoperative and postoperative nausea and vomiting in elective cesarean section patients. Eur J Obstet Gynecol Reprod Biol. 2013;169(2):184-188.
  18. Hu ML, Rayner CK, Wu KL, Chuah SK, Tai WC, Chou YP, et al. Effect of ginger on gastric motility and symptoms of functional dyspepsia. World J Gastroenterol. 2011;17(11):105-110.
  19. Shariatpanahi ZV, Taleban FA, Mokhtari M, Shahbazi S. Ginger extract reduces delayed gastric emptying and nosocomial pneumonia in adult respiratory distress syndrome patients hospitalized in an intensive care unit. J Crit Care. 2010;25(4):647-50.
  20. Van Tilburg MA, Palsson OS, Ringel Y, Whitehead WE. Is ginger effective for the treatment of irritable bowel syndrome? A double-blind randomized controlled pilot trial. Complement Ther Med. 2014;22(1):17-20.
  21. Halder A. Effect of progressive muscle relaxation versus intake of ginger powder on dysmenorrhoea amongst the nursing students in Pune. Nurs J India. 2012:103(4)152-157.
  22. Jenabi E. The effect of ginger for relieving of primary dysmenorrhoea. J Pak Med Assoc. 2013;63(1):8-10.
  23. Jiang Y, Turgeon DK, Wright BD, Sidahmed E, Ruffin MT, Brenner DE, Sen A, Zick S. Effect of ginger root on cyclooxygenase-1 and 15-hydroxyprostaglandin dehydrongenase expression in colonic mucosa of a human at normal and increased risk of colorectal cancer. Eur J Cancer Prev. 2013;22(5):455-460.
  24. Zick SM, Turgeon DK, Vareed SK, et al. Phase II study of the effects of ginger root extract on eicosanoids in colon mucosa in people at normal risk for colorectal cancer. Cancer Prev Res. 2011;4(11):1929-1937.
  25. Black CD, Herring MP, Hurley DJ, O’Connor PJ. Ginger (Zingiber officinale) reduces muscle pain caused by eccentric exercise. J Pain. 2010;11(9):894-903.
  26. Cady RK, Goldstein J, Nett R, Mitchell R, Beach ME, Browning R. A double-blind placebo-controlled pilot study of sublingual feverfew and ginger in the treatment of a migraine. Headache. 2011;51(7):1078-1086.
  27. Drozdov VN, Kim V a, Tkachenko E V, Varvanina GG. Influence of a specific ginger combination on gastropathy conditions in patients with osteoarthritis of the knee or hip. J Altern Complement Med. 2012;18(6):583-588.
  28. Mozaffari-Khosravi H, Talaei B, Jalali B-A, Najarzadeh A, Mozayan MR. The effect of ginger powder supplementation on insulin resistance and glycemic indices in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled trial. Complement Ther Med. 2014;22(1):9-16.
  29. Mansour MS, Ni Y-M, Roberts AL, Kelleman M, Roychoudhury A, St-Onge M-P. Ginger consumption enhances the thermic effect of food and promotes feelings of satiety without affecting metabolic and hormonal parameters in overweight men: a pilot study. Metabolism. 2012;61(10):1347-1352.
  30. Vahdat Shariatpanahi Z, Mokhtari M, Taleban FA, et al. Effect of enteral feeding with ginger extract in acute respiratory distress syndrome. J Crit Care. 2013;28(2):217.e1-217.e6.
  31. Sritoomma N, Moyle W, Cooke M, O’Dwyer S. The effectiveness of Swedish massage with aromatic ginger oil in treating chronic low back pain in older adults: a randomized controlled trial. Complement Ther Med. 2014;22(1):26-33.
  32. Maghbooli M, Golipour F, Esfandabadi AM, Youse M. Comparison between the efficacy of ginger and sumatriptan in the ablative treatment of a common migraine. Phytother Res. 2014;28(3):412-415.
  33. Basic Report: 11216, Ginger root, raw. Agricultural Research Service, United States Department of Agriculture website. Available here. Accessed February 23, 2015.

Food as Medicine: Prickly Pear Cactus (Opuntia ficus-indica, Cactaceae)

History and Traditional Use


Range and Habitat

The cactus genus Opuntia encompasses a large group of species characterized by flat, jointed or segmented pads known in botany as cladodes and in Spanish as nopales (singular: nopal).1 The cladodes are cylindrical or conical in shape, covered with clusters of spines, and are uniquely adapted to a dry desert climate due to thick, waxy stems that store water and minimize water evaporation in much the same way that leaves do.2 Yellow, orange, pink and red flowers grow on the plant. Pear-shaped fruits, called tunas, mature on the cactus pads in early fall. Two types of spines grow on the pads: large, fixed spines, and small, barbed spines that detach from the plant easily.3 The fruit often has clusters of smaller, inconspicuous spines and vary in color from green, yellow, red, orange, and purple. The fruit contains hard seeds surrounded by a fleshy portion. These succulent shrubs are drought-tolerant and grow in arid and semiarid climates. The prickly pear is native to Mexico but now grows across the United States, Australia, and South Africa.4 Prickly pear can be cultivated and propagated easily because the pads can be removed from the plant and replanted, forming a new growth.


Phytochemicals and Constituents

Opuntia species contain a variety of nutrients and bioactive compounds that are beneficial for human health. The pad and fruit compositions differ, but both provide various levels of macronutrient distribution, vitamins, minerals, and phytochemicals.

The fruits of the Opuntia species are rich in antioxidant pigments called betacyanins.5 Betacyanins from cactus pear fruit have been found to reduce low-density lipoprotein (LDL) cholesterol levels after consumption and protect against oxidation.6 Numerous flavonol glycosides, plant-derived secondary metabolites with important antioxidant properties, have been isolated from O. ficus-indica fruit concentrates.7

Pads of the Opuntia species contain manganese, which is essential for glucose metabolism8; magnesium, which helps the body regulate protein synthesis, muscle and nerve function, blood glucose, and blood pressure9; and vitamin C.

Historical and Commercial Uses

The prickly pear has been used traditionally in a variety of ways, including the treatment of digestive problems, edema, and topically for burn and wound care.10 The bitter plant also has been used as a diuretic, a fever reducer, for vitiligo (localized loss of pigmentation in the skin), urinary problems, tumors, abdominal fluid buildup, inflammation, liver problems, anemia, ulcers, bronchitis, hemorrhoids, bladder stones, inflammation of the eyes, lower back pain, spleen enlargement, and management of human immunodeficiency virus (HIV).3,11 Mashed pads historically were used to relieve heat and inflammation. They were also applied to boils for quick removal of pus. The flowers were used for lung problems, including bronchitis and asthma. The fruit of the plant was used to cool the body, treat gonorrhea and whooping cough, expel phlegm from the lungs, control excessive coughing, and increase bile secretion. Indigenous tribes in Mexico and the Pima tribe in central and southern Arizona use the cactus as a treatment for diabetes. Additional historical uses of the species include treatment of hangovers, prostate enlargement, and rabies.12

Opuntia cacti played an important role in the daily life and economy of the Aztec and Maya since they served not only as sources of food for humans and livestock but also as host plants for the cochineal insect (Dactylopius coccus).13 Cochineals are used to make carmine dye, a highly prized red dye for textiles. Carmine-dyed wool and cotton remain important mediums in Mexican folk art.

Currently, Opuntia is cultivated in arid and semiarid climates across the world including Mexico, Argentina, Brazil, Tunisia, Italy, Israel, China, Spain, and California.3,14 Uses of different components of the prickly pear encompass traditional uses as well as use for food and beverages, for livestock fodder, dye, soap, drinking water purification, thickening agent, and as a protective hedge for fencing.10 Mexico, Spain, Italy, northern Africa, and the United States commonly use the plant for food, consuming both the pad and the fruit.3

Modern Research

Treatment of diabetes has been cited as a traditional use for Opuntia, prompting research on its effects on various health parameters associated with diabetes. Rats with induced diabetes fed nopal flour from medium-sized pads followed by glucose were found to have a reduced post-meal glucose peak.15 A 40% reduction in fasting blood sugar was also seen in rats that consumed nopal flour, and a 30% decrease from treatment with nopal flour made with smaller pads. The results suggest that the maturity (as indicated by the size) of the pad modifies the blood sugar-lowering effects of Opuntia. The fiber found in the pad could be the primary component responsible for its blood sugar-lowering effects, delaying the absorption of carbohydrates from foods. Additional benefits have been found in animal studies: concentrated juice from the fruit of O. ficus-indica has been found to protect against ulcer formation in rats.7

Studies in humans have also explored the antidiabetic properties of prickly pear. A recent small study of type 2 diabetics found that consumption of steamed nopales significantly reduced spikes in blood glucose levels and serum insulin levels up to one hour after consumption of a high-carbohydrate breakfast.16 The study also found a significant decrease in the glucose-dependent insulinotropic peptide (a hormone released from the small intestine that stimulates insulin production17) after consumption of nopales and a high-carbohydrate breakfast. In pre-diabetics, a product formulated with both cladode and fruit skin extract of O. ficus-indica, named OpunDia™ (Martin Bauer Group, Vestenbergsgreuth, Germany), has been found to reduce blood glucose spikes 60, 90, and 120 minutes after ingestion followed by 75 g of a glucose solution.18

Studies have found additional uses for the fruit and cladodes of the prickly pear. The cladodes of the prickly pear cactus contain high levels of calcium and have been studied for their effects on bone mineral density. Urine calcium/creatinine levels decreased (increased urinary excretion of calcium can be a symptom of bone-destroying diseases, among other physiological abnormalities), and bone mineral density in the total hip region was increased in women 35 to 55 years old after daily consumption of 55 g of dehydrated nopal.19 Premenopausal women consuming 15 g of dehydrated nopal also had increased bone mineral density of the lumbar spine region. The 15 g of dehydrated nopal contained 500 mg of calcium and used nopales harvested at a high maturity stage. Furthermore, consumption of tortillas filled with cactus fruit jam increased blood antioxidant levels, blood vitamin C levels, and protected lipids from oxidation in human participants.20 The jam-filled tortillas also significantly reduced blood glucose, total cholesterol, and triglyceride levels. Some evidence of antiviral properties, immunomodulation, improvement of platelet function, and neuroprotection have also been noted.3

Interestingly, some research suggests that prickly pear may be a useful and practical tool for water filtration. A study from 2010 found that prickly pear gel filtered out 98% of bacteria in a contaminated water sample. The researchers noted that the cactus could “become a sustainable and affordable water purification method in the rural communities of developing countries.”21


Nutrient Profile22

Macronutrient Profile: (Per 100 g [approx. 1 1/4 cup sliced] raw nopal)

16 calories
1.3 g protein
3.33 g carbohydrate
0.1 g fat

Secondary Metabolites: (Per 100 g [approx. 1 1/4 cup sliced] raw nopal)

Very good source of:

Calcium: 164 mg (16.4% DV)
Vitamin C: 9.3 mg (15.5% DV)
Magnesium: 52 mg (13% DV)

Good source of:

Vitamin A: 457 IU (9.1% DV)
Dietary Fiber: 2.2 g (8.8% DV)
Potassium: 257 mg (7.34% DV)
Vitamin K: 5.3 mcg (6.63% DV)

Also provides:

Vitamin B6: 0.07 mg (3.5% DV)
Iron: 0.6 mg (3.33% DV)
Riboflavin: 0.04 mg (2.35% DV)
Niacin: 0.41 mg (2.05% DV)
Zinc: 0.25 mg (1.67% DV)
Phosphorus: 16 mg (1.6% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.


Recipe:
Cactus Casserole with Rice, Ancho Chili, and Cheese

Ingredients:

  • 2 dried ancho chilies, stems and seeds removed
  • 3/4 pound cactus pads (or 1 15-ounce jar/can of nopales, drained and rinsed)
  • 1 tablespoon canola or vegetable oil
  • 1/2 medium yellow onion, diced
  • 3 cloves of garlic, minced
  • 2 cups sour cream
  • 2 teaspoons ground cumin
  • 1 teaspoon dried oregano
  • 1/2 teaspoon ground allspice
  • 1/4 teaspoon cayenne pepper
  • 3 cups of cooked rice (white or brown)
  • 8 ounces Monterrey Jack cheese, shredded
  • Salt and pepper to taste

Directions:

  1. In a dry skillet over high heat, toast the chilies for about 10 seconds on each side, or until they begin to puff. Remove the chilies and soak in hot water until soft, about 20 minutes. Once hydrated, discard the soaking water and place the chilies in a blender or food processor with 1/4 cup of fresh water and blend until paste forms. Set aside.

  2. Heat the oven to 350° F.

  3. If using fresh cactus paddles: remove the thorns by trimming the thick base and edges of the paddle, then scrape the thorns with a paring knife without taking off too much of the green skin. Take care with this step; gloves are recommended. Thinly slice. Place the fresh cactus slices in a pot of water and bring to a boil. Reduce heat and simmer for 15 minutes. Drain and rinse well. Set aside.

  4. In a large skillet, heat the canola oil over medium heat. Add the onions and cook until translucent, about 5-7 minutes. Add garlic and cook for an additional minute, then remove the skillet from the heat. Set aside.

  5. In a bowl, mix together sour cream, prepared ancho chili paste, cumin, oregano, allspice, cayenne, and half of the shredded cheese. Add cooked rice, cactus, and onion-garlic mixture and stir to combine, tasting and adjusting seasoning as necessary. Pour the casserole into a greased baking dish and top with the remaining cheese.

  6. Bake uncovered for 30 minutes, until brown and bubbling.

References

  1. Loflin B, Loflin S. Texas Cacti: A Field Guide. College Station, TX: Texas A&M University Press; 2009.
  2. Nobel, PS. Ecophysiology of Opuntia ficus-indica. In: Mondragón-Jacobo C and Pérez-González S, eds. Cactus (Opuntia spp.) as Forage. Rome, Italy: Food and Agriculture Organization of the United Nations; 2001:13-20.
  3. Chauhan SP, Sheth NR, Jivani NP, Rathod IS, Shah PI. Biological actions of Opuntia species. System Rev Pharm. 2010;1(2):146-151.
  4. Van Wyck BE. Food Plants of the World: An Illustrated Guide. Portland, OR: Timber Press; 2006.
  5. Castellar R, Obón J, Alacid M, Fernández-López JA. Color properties and stability of betacyanins from Opuntia fruits. J Agric Food Chem. 2003;51(9):2772-2776.
  6. Tesoriere L, Allegra M, Butera D, Livrea MA. Absorption, excretion, and distribution of dietary antioxidant betalains in LDLs: potential health effects of betalains in humans. Am J Clin Nutr. 2004;80(4):941-945.
  7. Galati EM, Mondello MR, Giuffrida D, et al. Chemical characterization and biological effects of Sicilian Opuntia ficus indica (L.) Mill. fruit juice: antioxidant and antiulcerogenic activity. J Agric Food Chem. 2003;51(17):4903-4908.
  8. Emsley J. Nature’s Building Blocks: An A-Z Guide to the Elements, 2nd ed. Oxford, UK: Oxford University Press; 2011.
  9. Magnesium: Fact Sheet for Health Professionals. National Institutes of Health Office of Dietary Supplements website. November 4, 2013. Available here. Accessed August 17, 2015.
  10. Shetty AA, Rana MK, Preetham SP. Cactus: a medicinal food. J Food Sci Technol. 2012;49(5):530-536.
  11. Kaur M, Kaur A, Sharma R. Pharmalogical actions of Opuntia ficus-indica: A review. J App Pharm Sci. 2012;2(7):15-18.
  12. Dvorkin-Camiel L, Whelan JS. Tropical American plants in the treatment of infectious disease. J Diet Suppl. 2008;5(4):349-372.
  13. Gibson AC. Red Scales in the Sunset. UCLA College of Life Sciences – Mildred E. Mathias Botanical Garden website. Available here. Accessed August 17, 2015.
  14. Stintzing F, Carle R. Cactus stems (Opuntia spp.): A review on their chemistry, technology, and uses. Mol Nutr Food Res. 2005;49(2):175-194.
  15. Nuñez-López MA, Paredes-López O, Reynoso-Camacho R. Functional and hypoglycemic properties of nopal cladodes (O. ficus-indica) at different maturity stages using in vitro and in vivo tests. J Agr Food Chem. 2013;61(46):10981-10986.
  16. López-Romero P, Pichardo-Ontiveros E, Avila-Nava A, et al. The effect of nopal (Opuntia ficus indica) on postprandial blood glucose, incretins, and antioxidant activity in Mexican patients with type 2 diabetes after consumption of two different composition breakfasts. J Acad Nutr Diet. 2014;114(11):1811-1818.
  17. Glucose-dependent insulinotropic peptide. The Free Dictionary website. Available here. Accessed September 10, 2015.
  18. Godard MP, Ewing BA, Pischel I, Ziegler A, Benedek B, Feistel B. Acute blood glucose lowering effects and long-term safety of OpunDia™ supplementation in pre-diabetic males and females. J Ethnopharmacol. 2010;130(3):631-634.
  19. Aguilera-Barreiro M, Rivera-Márquez JA, Trujillo-Arriaga HM, Tamayo y Orozco JA, Barreira-Mercado E, Rodríguez-García ME. Intake of dehydrated nopal (Opuntia ficus indica) improves bone mineral density and calciuria in adult Mexican women. Food Nutr Res. 2013;57:19106-19115.
  20. Guevara-Arauza J, Paz J, Mendoza S, Guerra R, Maldonado L, González D. Biofunctional activity of tortillas and bars enhanced with nopal. Preliminary assessment of functional effect after intake on the oxidative status in healthy volunteers. Chem Cent J. 2011;5:10-20.
  21. Cactus purifies water on the cheap, finds study. SciDevNet website. Available here. Accessed September 10, 2015.
  22. Basic Report: 11963, Nopales, raw. Agricultural Research Service, United States Department of Agriculture website. Available here. Accessed August 17, 2015.

Food as Medicine: Okra (Abelmoschus esculentus, Malvaceae)

History and Traditional Use


Range and Habitat

Okra (Abelmoschus esculentus) is a naturalized tropical and subtropical annual grown extensively in Asia and Africa. Growing up to 6 feet in height, okra plants have sturdy stems, long, broad, serrated, deeply-lobed leaves, and delicate yellow flowers marked with red or purple color toward the base.1,2 The edible portion of okra is the immature pod or fruit which contains the seeds.3 Inside the tapering, the fuzzy pod is a soft tissue that exudes a mucilaginous (sticky) juice when cooked.4 The pods are commonly green, but other varieties have red or burgundy pods. Considered one of the most reliable annual edible vegetable crops of the tropics (the Latin term esculentus means edible), okra is tolerant of both hot, dry as well as hot, humid climates and is widely cultivated in West Africa, India, Southern Europe, and the Americas.5

Related to hibiscus (Hibiscus sabdariffa) and marshmallow (Althaea Officinalis), okra was originally classified in the genus Hibiscus and was later reclassified into the genus Abelmoschus in the 18th century.3 Okra is believed to have originated in Ethiopia, where it still grows wild, although there is no definitive proof of its origin.3 Okra has been cultivated by the Egyptians since the 12th century BCE. From there it traveled to central Africa, the Mediterranean, and India.6 By the 17th century CE, okra had reached the New World via the slave trade in Africa and by the 19th century, it had spread to China.2

Phytochemicals and Constituents

Okra is comprised primarily of water, carbohydrates, and protein with very little fat and a fair amount of dietary fiber.3 Okra is also a significant source of vitamin C and contains many other micronutrients such as calcium, phosphorus, iron, beta-carotene, and B vitamins. The carbohydrate content of okra is primarily in the form of mucilage, a long chain polysaccharide molecule made up of sugar units and amino acids. Thin-layer chromatography analytical methods indicate that the polysaccharides in okra gum contain galactose, galacturonic acid, rhamnose and glucose.7 This water-soluble mucilage is the source of okra’s viscous, slippery consistency, which is linked to okra’s effectiveness in treating gastritis and other conditions where the mucilage acts as a demulcent agent, i.e., it provides relief to inflamed mucous membranes.

Phytochemical studies show that okra pods contain flavonoids, tannins, sterols, and triterpenes.5Flavonoids are important compounds that are responsible for protecting tissues from oxidative damage in a variety of ways. Quercetin is the major antioxidant in okra gum, which is a key player in controlling inflammation in the body.7

Okra contains a moderate amount of oxalate, a compound that both is created by the human body and is present in plants. Because oxalate is excreted through urine and can calcify in the kidneys, high levels of oxalate intake along with genetic predisposition may lead to the development of kidney stones. Different types of kidney stones exist, but approximately 75% of patients diagnosed with kidney stones in the United States suffer from stones made of calcium oxalate.8 Physicians may recommend that patients with kidney stones or with a history of kidney stones follow a low-oxalate diet; however, a food’s oxalate content does not necessarily correlate with its oxalate bioavailability in the human body. Okra has been shown to have low oxalate bioavailability as compared to similar oxalate-rich foods such as peanuts (Arachis hypogaea) and almonds (Prunus dulcis).9 Oxalate absorption from dietary sources can be reduced when paired with foods with high calcium or magnesium content.10

Historical and Commercial Uses

Ancient cultures quickly noted okra’s mucilaginous nature and its subsequent benefits to the digestive system. Okra was used by Egyptians to prevent the development of kidney stones.5 In folkloric practice, fresh, tender okra pods were consumed to cure constipation, leucorrhea (abnormal vaginal discharge), spermatorrhea (excessive, involuntary ejaculation), diabetes, and jaundice. The mucilage from okra is used commonly in traditional Asian and African medicine to treat gastritis, gastric ulcers, and to lubricate the intestines.5,11,12

The acceptance of okra as a relatively modern medicinal agent can be found in J.M. Nickell’s Botanical Ready Reference, a book published in 1911 in the United States for physicians and pharmacists.13 Arranged alphabetically by Latin binomial, okra appears as the first entry on the list of herbal drugs and medicinal agents. The actions noted for okra capsule (fruit) are “mucilaginous, demulcent, and edible.”

Okra mucilage has been used traditionally in Arabic, West African, Caribbean, and Eastern Mediterranean cooking.6 The most common culinary application of okra is as a thickener for soups and stews. The most well-known application may be in Louisiana’s Creole gumbo stew, which may derive its name from a corruption of the Bantu word for okra: kingombo. It is also used as a substitute for egg whites and as a fat replacement in chocolate bars, cookies, and frozen dairy desserts.7 Okra can be boiled, baked, sautéed, stuffed, or fried. Sautéing or quickly frying the okra reduces the sticky texture significantly.4 The gummy texture can also be mitigated by cooking okra with cornmeal.14

The water extract of okra, also known as okra gum, is used as an industrial lubricant and as an emulsifier to stabilize foams and suspensions.9 It is also utilized medically in plasma replacement therapy.3 The seeds of the okra pods are roasted and powdered into a flour for use as a coffee substitute in Turkey, and in Nigeria, the nutritious flour is an important staple and often added to soups and other foods.4,15

In vitro studies done on the chemical composition and antioxidative properties of Nigerian okra, seed flour demonstrated that antioxidant activity correlated positively with roasting time.15 This study showed that antioxidants within the okra seeds had the greatest benefit in protecting the human large intestine from oxidative damage.

okraModern Research

Laboratory research suggests that okra and its extracts can be useful in the treatment of a variety of disease states. A recent in vitro study indicated that Abelmoschus esculentus lectin (AEL), a protein extracted from okra, binds carbohydrates on the surface of cancer cells, thus causing apoptosis (programmed cell death) and significantly and selectively inhibiting breast cancer cell proliferation.16

Modern research suggests that okra’s effectiveness in the treatment of gastrointestinal complaints can be attributed to the presence of rhamnogalacturonan polysaccharides, which disrupt the adhesion of Helicobacter pylori bacteria to stomach tissue;11 these bacteria are associated with stomach ulcers.

The polysaccharide compounds bind non-specifically to different strains of H. pylori, inhibiting the binding of the pathogens to gastric cells. The rhamnogalacturonan’s appear to interact with H. pylori’s surface proteins, potentially providing a preventative treatment approach. Okra’s mucilage could also inhibit the recurrence of H. pylori infections by preventing re-colonization of the stomach following antibiotic eradication therapy.

An in vitro study published in 2007 by the USDA Agricultural Research Service compared the effectiveness of the bile acid-binding, cholesterol-lowering drug cholestyramine to the natural bile acid-binding ability of the common vegetables okra, beets (Beta vulgaris), asparagus (Asparagus Officinalis), eggplant (Solanum malongena), turnips (Brassica rapa subsp. rapifera), green beans (Phaseolus vulgaris), carrots (Daucus carota subsp. sativus), and cauliflower (B. oleracea var. botrytis).17 Okra was found to be more effective at binding bile acids than any other vegetable evaluated in the study, and 34% as effective as cholestyramine.

An animal study conducted in 2011 found that okra peel and seed powder had the ability to normalize blood levels of both lipids and sugars in diabetic rats.18 Oral administration of okra significantly reduced blood levels of total cholesterol, triglycerides, low-density lipoproteins (LDL), very low-density lipoproteins (VLDL), and hemoglobin A1C as well as significantly increased blood levels of high-density lipoproteins (HDL) and hemoglobin. While both parts of the plant were effective in a dose-dependent manner, the seed powder had a more pronounced effect than the peel, especially on blood glucose levels. These results indicate that consumption of okra may help reduce hyperlipidemia and hyperglycemia in diabetics, thus helping to prevent cardiovascular disease and other comorbidities associated with diabetes. These effects could be related to okra’s ability to bind bile acids.

Among other factors (e.g., soil, climate, season, etc.), cooking and preparation methods can impact the nutrient content of vegetables. A study on the effects of different cooking methods on the nutrient content of okra pods compared the mineral content of raw and cooked okra of both organic and conventional varieties.19 Raw okra had the highest concentration of all elements tested, indicating some degree of nutrient losses during cooking, with the most pronounced difference found in potassium concentration, while calcium losses were relatively minimal.

There were significant mineral losses following boiling and baking, but the effect was less pronounced with sautéing.19 This could be due to the water solubility of nutrients found in okra, including but not limited to its mucilage. While the loss of mineral content may seem undesirable, the marked reduction of minerals from cooking could be beneficial for those with kidney disease. For example, potassium levels can be reduced by up to 60% by boiling okra and pouring off the water, making boiled okra safer than raw okra for a potassium-restricted diet.

An in vitro study in 2011 examined the effects of okra gum extract on both cell viability and bacterial growth.7 Okra gum extract had antibacterial effects on seven of eight strains of bacteria tested, and was most effective against Staphylococcus aureus, Mycobacterium sp., M. aurum, Xanthobacter Py2, and Pseudomonas aeruginosa. In fact, okra gum extract was completely effective in inhibiting the growth of S. aureus (which can cause skin infections, pneumonia, meningitis, and septicemia) as well as P. aeruginosa(known for causing fatal lung infections in patients with cystic fibrosis). Major lipid fractions isolated from okra gum extract were 34% palmitic acid and 26% stearic acid, both of which have antibacterial properties against S. aureus and Listeria monocytogenes. The results of this study demonstrate the potential use of okra extract as an antibacterial agent with possible applications in the food and pharmaceutical industry.

A study on rats explored the traditional uses of okra in liver disease.5 Hepatotoxicity was induced in rats that were then given an okra gum extract that quenched all free radicals present, thus preventing lipid peroxidation of liver cell membranes. The hepatoprotective and antioxidant activities of the okra extract are comparable to standard silymarin, isolated from milk thistle (Silybum marianum) fruit, making okra extract a potentially important substance for protecting chemically-damaged liver tissue. Human clinical trials are needed to explore this potential therapeutic application.


Nutrient Profile20

Macronutrient Profile: (Per 1 cup [approx. 100 g] raw okra pods)

33 calories
2 g protein
7.5 g carbohydrate
0.2 g fat

Secondary Metabolites: (Per 1 cup [approx. 100 g] raw okra pods)

Excellent source of:

Vitamin K: 31.3 mcg (39.1% DV)
Vitamin C: 23 mg (38.3% DV)

Very good source of:

Folate: 60 mcg (15% DV)
Vitamin A: 716 IU (14.32% DV)
Magnesium: 57 mg (14.3% DV)
Thiamin: 0.2 mg (13.3% DV)
Dietary Fiber: 3.2 g (12.8% DV)
Vitamin B6: 0.22 mg (11%DV)

Good source of:

Potassium: 299 mg (8.5% DV)
Calcium: 82 mg (8.2% DV)
Phosphorus: 61 mg (6.1% DV)
Niacin: 1 mg (5% DV)

Also provides:

Zinc: 0.6 mg (4% DV)
Iron: 0.6 mg (3.3% DV)
Vitamin E: 0.27 mg (2.5% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet.

Recipe: Spicy Okra Stew

Adapted from New Flavors for Vegetables21
Ingredients:

  • 3 large ripe tomatoes
  • 1 lb fresh okra, stems removed, sliced 1/4-inch thick
  • 2 tablespoons canola oil
  • 1 yellow onion, diced
  • Salt and freshly-ground black pepper, to taste
  • 2 cloves of garlic, minced
  • 1/2 teaspoon cayenne pepper
  • 1/2 teaspoon ground coriander
  • 1/2 teaspoon ground cumin
  • 1/4-1/3 cup fresh parsley, chopped

Directions:

  1. Prepare a small saucepan of boiling water and a separate bowl of ice water. Blanch the tomatoes: cut a shallow “x” at the bottom of each tomato, then cook in boiling water for 10 seconds. Immediately submerge in the ice water, let stand for 10 more seconds, then drain. Peel the skin from the tomatoes and chop the flesh.

  2. Heat the oil in a saucepan over medium heat. Add the onions and cook until just softened, 2-3 minutes. Add the okra and sauté until lightly browned, approximately 10 minutes, then lower the heat to medium-low and cook until tender.

  3. Add the garlic, salt, pepper, and spices, stirring until combined and fragrant, then add the tomatoes and 1 cup of water. Simmer until the tomatoes have broken down and the mixture begins to thicken. Adjust seasoning to taste, then remove from heat and stir in the chopped parsley.

References

  1. Van Wyck B. Food Plants of the World. Portland, OR: Timber Press; 2006.
  2. Madison D. Edible: An Illustrated Guide to the World’s Food Plants. Washington, DC: National Geographic Society; 2008.
  3. Benchasri S. Okra (Abelmoschus esculentus (L.) Moench) as a valuable vegetable of the world. Ratarstvo i povrtarstvo. 2012:49:105-112.
  4. Onstad D. Whole Foods Companion: A Guide for Adventurous Cooks, Curious Shoppers, and Lovers of Natural Foods. White River Junction, VT: Chelsea Green Publishing; 2004.
  5. Alqasoumi SI. ‘Okra’ Hibiscus esculentus L.: A study of its hepatoprotective activity. Saudi Pharmaceutical Journal. 2012:20:135-141.
  6. Green A. Field Guide to Produce: How to Identify, Select, and Prepare Virtually Every Fruit and Vegetable at the Market. San Francisco, CA: Quirk Books; 2004.
  7. de Carvalho CCCR, Cruz PA, da Fonseca MR, et al. Antibacterial properties of the extract of Abelmoschus esculentus. Biotechnology and Bioprocess Engineering. 2011:16:971-977.
  8. Nephrology Department. Oxalate Content of Foods. The Children’s Medical Center of Dayton website. July 14, 2005. Available here. Accessed July 16, 2015.
  9. Brinkley LJ, Gregory J, Pak CY. A further study of oxalate bioavailability in foods. J Urol. 1990;144(1):94-96.
  10. Liebman M, Al-Wahsh IA. Probiotics and other key determinants of dietary oxalate absorption. Adv Nutr. 2011;2:254-260. Available here. Accessed July 16, 2015.
  11. Messing J, Thole-C, Niehues M, et al. Antiadhesive properties of Abelmoschus esculentus (okra) immature fruit extract against Helicobacter pylori adhesion. PLoS ONE. 2014:9(1):[e84836].
  12. Pitchford P. Healing with Whole Foods: Oriental Traditions and Modern Nutrition. Berkeley, CA: North Atlantic Books; 1993.
  13. Nickell JM. J.M. Nickell’s botanical ready reference: specially designed for druggists and physicians: containing all of the botanical drugs known up to the present time, giving their medical properties, and all of their botanical, common, pharmacopoeial and German common (in German) names. Chicago, IL: Murray & Nickell Mfg. Co.; 1911.
  14. Davidson A. The Oxford Companion to Food. Oxford, UK: Oxford University Press; 1999.
  15. Adelakun OE, Oyelade OJ, Ade-Omowaye BIO, et al. Chemical composition and the antioxidative properties of Nigerian okra seed (Abelmoschus esculentus Moench) flour. Food and Chemical Toxicology. 2009:47:1123-1126.
  16. Monte LG, Santi-Gadelha T, Reis LB, et al. Lectin of Abelmoschus esculentus (okra) promotes selective antitumor effects in human breast cancer cells. Biotechnol. Lett. 2014:36:461-469.
  17. Kahlon TS, Chapman MH, Smith GE. In vitro binding of bile acids by okra, beets, asparagus, eggplant, turnips, green beans, carrots, and cauliflower. Food Chemistry. 2007:103:676–680.
  18. Sabitha V, Ramachandran S, Naveen KR, et al. Antidiabetic and antihyperlipidemic potential of Abelmoschus esculentus (L.) Moench. in streptozotocin-induced diabetic rats. Journal of Pharmacy and Bioallied Sciences. 2011:3:397-402.
  19. Ivanice F, Ana MP, Uenderson A, et al. Multivariate analysis of the mineral content of raw and cooked okra (Abelmoschus esculentus L.). Microchemical Journal. 2013:110:439-443.
  20. Basic Report: 11278, Okra, raw. Agricultural Research Service, United States Department of Agriculture website. Available here. Accessed July 16, 2015.
  21. Liano J. Williams-Sonoma New Flavors for Vegetables: Classic Recipes Redefined. Birmingham, AL: Oxmoor House; 2008.

Medicinal Rich Tomatoes

The tomato plant (botanical name Solanum Lycopersicum) is a member of the nightshade family. Usually, plants of this species grow to a height of anything between one and three meters (3 to 10 feet) and have a very delicate stem that generally spread out over the ground as well as climbs like vines on other nearby plants. Tomato is a perennial plant in its place of origin but is generally cultivated outdoors as an annual plant in places having temperate climatic conditions.

It is thought that the existing kind of tomato has originated from a species whose fruits were roughly the size of marbles and this species actually grew several thousand years back. In effect, the tomato is indigenous to South America’s Andean region and there is evidence that this species was cultivated in Peru as early as the 16th century when the Spanish conquered the region. Prior to the end of the 16th century, people in England, as well as the Netherlands, were consuming as well as taking delight in tomato. While the English nicknamed the fruit as ‘love apple’, romances in England portrayed tomato in the form of a symbol of fondness or love. According to the cultivators as well as its usage, the tomato is considered to be a vegetable, while in terms of botany, the tomato is regarded as a fruit. However, going by botany, the tomato may be categorized as a berry, as it is yielding and encloses one or several seeds, which are not stones. Tomato is regarded to be an important fruit, which is a good source of citric acid and is classified in the same group that also includes oranges and grapefruit. In addition to citric acid, tomato also contains some amount of oxalic acid.

The utmost benefits of tomatoes can be obtained when they are mixed with proteins. You may use tomatoes in the form of fruits as well as in vegetable salads. When tomatoes are used in beverages, they provide a calming and rejuvenating feeling and are particularly wonderful in the form of flavoring for soups. In addition, tomatoes may be used in foods to provide color as well as to make green salads additionally tempting. It is advisable that you need to use tomato juice soon after it has been extracted from tomato or soon after the can containing the juice is opened. In case canned tomato juice is opened and allowed to remain in the same way, it will lose a great deal of its mineral worth since it oxidizes very rapidly.

Tomatoes should also be collected when they are ripe since the acids of the green tomatoes are extremely harmful to the body and have a negative reaction on the kidneys. Several varieties of tomatoes that are cultivated in the present times are grown in hothouses and are collected when they are still unripe and green. These unripe tomatoes eventually ripen while being transported to the markets or during the period when they are in cold storage plants, which are constructed for this purpose. When the seeds or the internal parts of the tomatoes remain green, while the exterior is red, it is a sign of the fact that the fruit has been picked prematurely.

heirloom_tomatoes-1

Medicinal Components of Tomato:

A tomato basically does not form acid. Although it encloses sufficient amount of citric acid, it is actually alkaline forming when it gets into our bloodstream. Tomato enhances the alkalinity of the blood and, thereby, facilitates in removing toxins, particularly uric acid, from the system. Tomatoes are excellent in the form of a liver cleanser, particularly when they are used in conjugation with juices of green vegetables.

In several European clinics or sanatoriums, tomatoes are employed in the form of a poultice for treating several health conditions. Some people have a wrong belief that tomatoes are detrimental for people who have been enduring gout and rheumatism. In effect, individuals who are suffering from these two conditions ought to blend tomato juice with juices of other green vegetables with a view to averting any type of possible potent reaction. Every time when it is found that the blood is sluggish in any area of the body, applying a tomato poultice is an excellent treatment for easing the blood stagnation. Applying a tomato poultice works as a suspending agent or in the form of a solvent.

Tomatoes are extremely rich in vitamin content, tomatoes are excellent in the form of blood purifier and are very good in elimination diets. Nevertheless, they ought not to be employed regularly. It may be noted that tomato juice may also be employed in convalescent diets, in conjugation with juices of other raw vegetables, for instance, parsley, celery, carrot and beet juice.

Tomatoes contain a substance called lycopene, which belongs to the carotenoid family and is a pigment that is responsible for the red color of the vegetable/ fruit. In addition, lycopene is the main contributor to the tomatoes’ power to promote health. In effect, lycopene has shown a variety of exceptional as well as individual biological characteristics that have always fascinated scientists. A number of researchers have started believing that lycopene could be a very potent antioxidant, somewhat similar to beta-carotene. It has been proved that lycopene eliminates the free radical singlet oxygen, an especially toxic form of oxygen extremely proficiently. In addition, lycopene also has the capacity to scavenge a number of free radicals.

Findings of several types of research have begun to divulge that individuals who have consumed excessive amounts of tomatoes faced far little risks of death from all types of cancers in comparison to those who consumed very little or no tomatoes at all. Several other types of research have repeated the positive findings regarding the consequences of consuming tomatoes.

Lycopene found in tomatoes does not only help to alleviate cancer. In effect, this member of the carotenoid family is a crucial part of the antioxidant protection system in our skin. On its own as well as in conjunction with additional nutrients, dietary lycopene may increase the skin’s sun protection factor (SPF). Precisely speaking, when you consume tomatoes, you actually augment the ability of your skin to endure the battering from the harmful rays of the sun. Tomatoes work in a manner akin to an internal sunblock.

In addition, lycopene also has the ability to obliquely lower the risk for macular degeneration related to age by means of ‘releasing’ lutein oxidation to enable transportation of lutein to the macula in its un-oxidized and defensive form.

It may be noted that lycopene is rarely present in foods, and tomatoes are among just a few foods that enclose this potent antioxidant. In fact, the red watermelon is one more wonderful natural source of lycopene. According to some sources, lycopene is an extremely intense and bio-available source of the nutrient, which is present in more amounts in red watermelon compared to tomatoes. In fact, consuming watermelon certainly boosts the amount of lycopene in the blood more in comparison to tomatoes.

Although in recent times, lycopene has drawn plenty of attention, tomatoes enclose rich amounts of a range of nourishment’s that appear to work in synergy to support health as well as energy. The good thing about the tomato is that while it contains low-calorie content, it is high in fiber and potassium. In addition to having rich contents of lycopene, tomatoes are also an excellent natural resource of alpha-carotene, beta-carotene, phytoene/ phytofluene, lutein/ zeaxanthin as well as a variety of polyphenols. Tomatoes also enclose a few B vitamins, including vitamin B6, pantothenic acid, thiamine, and niacin. In addition, they contain some amount of vitamin E, folate, manganese, magnesium, and zinc.

Tomatoes and cancer: Many of the very thrilling researches undertaken on tomatoes have concentrated on the fruit/ vegetable’s competency to provide protection against cancer, particularly prostate cancer.

Tomatoes do not only protect us from prostate cancer. In effect, an increasing amount of evidence hint that to some extent, lycopene offers protection from other forms of cancers too – such as digestive tract, breast, bladder, cervix and lung cancer.

It appears that lycopene lowers the risk of cancer in various different manners. In the form of a potent antioxidant, lycopene assists in blocking the constant degenerative effects of the harmful free radicals inside the body. Lycopene is particularly effectual for this purpose when there is the presence of adequate vitamin E. In effect, lycopene also appears to obstruct the growth aspects that encourage the growth as well as the proliferation of cancer cells. And lastly, it also appears that lycopene also encourages the body to increase a further effectual immune protection against cancer.

Since lycopene is soluble in fat, it requires some amount of dietary fat to transport this potent antioxidant through the bloodstream. However, it needs to be mentioned that consuming a whole, fresh tomato out of your hand is not a very good source of this nourishment – lycopene. The most effective foods based on a tomato that appears to provide maximum protection against cancer are prepared with some amount of oil at all times. A salad prepared with tomato with added virgin olive oil is a food that genuinely promotes health. It may be noted that the greenish hue of olive oil signifies the existence of polyphenols. When these polyphenols contained by virgin olive oil are blended with the potent nourishment’s present in tomatoes, it gives spaghetti sauce a healthy flavor to treat on. It may also be used in soups based on tomatoes for the same purpose.

Tomatoes excellent for the heart: Besides being an effective food for protection against cancer, there is sufficient evidence that consuming tomatoes also has a crucial role in lowering the risk of cardiovascular ailments. Lycopene’s antioxidant function in conjugation with other potent antioxidants present in tomatoes, for instance, beta-carotene and vitamin C, work within the body to combat the harmful free radicals that might otherwise harm the cells as well as cell membranes. The protection of the cells, as well as their membranes, lowers the risks of inflammation and, hence, the advancement as well as acuteness of atherosclerosis. In fact, lycopene present in tomatoes has been found to be very effectual in providing protection against heart attacks.

Healthy skin: When the tomato plants are growing outdoors in the wild, they need to guard themselves against any possible attack. In fact, these plants are under continuous assault from the ultraviolet rays (UV rays), predators as well as environmental pollution. Hence, it is very important that these plants should have a first, strong line of protection. In the case of humans as well as other living things, the skin is the first line of defense. Be it the skin or peel of an apple, the covering of a grape or the outer layer of an orange, this portion of the fruit possesses wonderful antioxidant competence that allows it to endure the attacks of nature.

For instance, the exterior leaves of cabbage and spinach have the maximum concentrations of vitamin C, while the florets of broccoli have additional vitamin C compared to its stalks.

For example, 100 grams of fresh apple (peels included) enclose approximately 142 mg of flavonoids. On the other hand, an equal amount of apples without their skin or peel enclose just 97 mg of flavonoids. A very common flavonoid known as quercetin which has anti-inflammatory attributes is only present in the peel of the apples and not in the fruit’s flesh. In other words, the antioxidant actions of 100 grams of apples sans its skin or peel are about 55 per cent of the actions of 100 grams of apples having its skin. More precisely, apples without their peel are just about 50 percent as potent as those with their skin. Similarly, the paper-thin brown hued skins on peanuts as well as almonds are packed with a range of bioactive polyphenols.

It is advisable that you consume the right fruits and vegetables that have their skin/ peel or rind on. In fact, the skin is also the place where the detrimental pesticides and latently harmful bacteria may be found. Therefore, it is essential to meticulously wash the fruits and vegetables prior to eating them raw. At the same time, do not forget that while drinking juices of vegetables and fruits, it is important to choose the ones with sediments at the bottom. These sediments actually contain portions of the skin and pulp of the vegetables and fruits and they are all vital sources of antioxidants.

Food as Medicine: Rutabaga (Brassica napus subsp. rapifera, Brassicaceae)

Rutabaga (Brassica napus subsp. rapifera, Brassicaceae), also known as “swede” or “Swedish turnip,” is a natural hybrid between cabbage (B. oleracea) and turnip (B. rapa).1 It can also be found under the subspecies “napobrassica.” Considered a root vegetable, the rutabaga is actually the enlarged base of the stem of the plant.2 Most commonly, rutabagas have a pale yellow or white inner flesh and a darker yellow or purple exterior.

Rutabaga is a relative newcomer to the world of domesticated crops, with its first mention in botanical literature appearing in the 17th century.3 The nickname “swede” comes from the plant’s geographical origin, as it became a fixture in Swedish agriculture before spreading around the world.4 It was introduced in North America in the early 19th century.

A biennial plant that stores well, rutabaga thrives in cooler climates where the summer season is not excessively hot.5 Rutabagas are considered a root crop and lend themselves to longer post-harvest storage when placed in a root cellar or similar environment that is damp and cool, lasting up to six months in storage.6,7 To prevent loss of moisture during storage or transit, the green tops are removed and the bulbs are waxed.5


Phytochemicals and Constituents

Rutabagas are rich in carbohydrates and fiber and contain little fat or protein.8 They contain about half of the calorie content of potatoes and are relatively high in vitamin C and potassium.

A diet high in fiber has many benefits, primarily for the gastrointestinal tract.9 Insoluble fiber, which cannot be absorbed and digested, promotes healthy bowel movements and lowers the risk of developing disorders such as acid reflux, ulcers, constipation, hemorrhoids, and diverticulosis, a condition in which small, bulging pouches develop along the digestive tract. These pouches can become inflamed, which is known as diverticulitis, causing abdominal pain and fever and requiring treatment. The fiber content of rutabagas consists mostly of insoluble fiber, which, in addition to maintaining bowel health, may also lower the risk of cardiovascular disease, hypertension, diabetes, stroke, and obesity.10

Potassium is an essential mineral for the body. It functions as an electrolyte, conducting electricity through the body, ensuring the proper function of cells, tissues, and organs.11 Other important electrolytes include sodium, chloride, calcium, and magnesium. Maintaining healthy potassium levels is vital for maintaining bone health, especially for the aging population, and people with diets high in potassium are at lower risk for stroke and heart disease. Additionally, potassium levels depend on an inverse relationship with salt intake: those who consume too much sodium in proportion to potassium will have less potassium available for absorption by the body.12

Other bioactive components in rutabagas include glucosinolates and phenols, similar to other plants in the Brassicaceae family, such as broccoli (Brassica oleracea)13. Glucosinolates are precursors to isothiocyanates, which may reduce the risk of certain cancers.14 In the plant, glucosinolates are converted to isothiocyanates by an enzyme called myrosinase. However, the enzyme is deactivated with excessive heat so cooking rutabaga will impact the conversion of glucosinolates to isothiocyanates. Gut bacteria also have this ability to convert glucosinolates to isothiocyanates. Phenols act as antioxidants, which reduce free radicals in the body.


Historical and Commercial Uses

The cultivation of rutabagas began in the 1600s in Bohemia (which now makes up the western Czech Republic) before they made their way to Scandinavia, where the cold-weather crop was embraced as both foods for humans and livestock.6 By the 18th century, rutabaga consumption had spread to France and England.2 Rutabagas were introduced in the United States in the early 19th century, where they were primarily grown as livestock fodder. Because the plant is so hardy and grows well in bad weather conditions, rutabagas became associated with times of scarcity, which impacted their popularity as a food product. Even in modern times in the United States, they are not as widely consumed as other, more familiar root vegetables. However, the rutabaga has had some interesting cultural impacts.

Jack o’ lanterns are a Halloween tradition with roots in Irish culture. The origin myth tells the story of a trickster named Jack, who thwarted the devil’s plan to take his soul and found his way out of hell with the aid of a burning ember and a hollowed-out rutabaga (or “turnip”).15 Though the rutabaga’s colloquial name of “turnip” in the British Isles has resulted in the erroneous belief that Brassica rapa was used, it is accepted by the standard lore that rutabagas were, in fact, the first jack o’ lanterns. When the practice migrated to the United States, where pumpkins (Cucurbita pepo, Cucurbitaceae) were readily available and already involved in many fall celebrations, the pumpkin replaced the rutabaga.

Many towns with a prominent Scandinavian population have events to celebrate the rutabaga and its place in cultural traditions. One of the more tongue-in-cheek celebrations is the International Rutabaga Curl competition, which has been a tradition in Ithaca, New York, since 1996.16 Notably, in 2016, the town of Cumberland, Wisconsin, held its 84th Annual Rutabaga Festival Parade.
Modern Research

In a recent study, rutabaga methanol extracts killed human liver cancer cells in vitro and also decreased the rate of cancer cell proliferation.17 The normal, non-cancerous cells were not affected. Compared to root or seed extracts, rutabaga sprout extracts were more effective at battling liver cancer cells. This was due to the significantly higher levels of flavonoids found in the rutabaga sprout, which correlated to stronger antioxidant activity.

Rutabaga is a variety of the rapeseed plant (Brassica napus, Brassicaceae).Brassica napus contain plant sterols that, in isolation, have shown effects against prostate cancer cells.18 The sterol called brassinolide induced apoptosis (normal, pre-programmed cell death) in these prostate cancer cells during in vitro trials. Researchers concluded that brassinolide “might, therefore, be a promising candidate for the treatment of prostate cancer.”

The bioactive compounds present in cruciferous vegetables, including rutabagas, have been studied for many different conditions. A randomized, crossover, controlled study showed that intestinal bacteria were changed within two weeks of eating a diet rich in cruciferous vegetables, although the bacterial colonization was different with each study participant.19 A hospital-based, case-control study showed that consumption of raw, rather than cooked, cruciferous vegetables decreased the risk of bladder cancer.20Additionally, growth conditions can impact the glucosinolate content in cruciferous vegetables.21Supplementing the soil with selenium, nitrogen, or sulfur was correlated with an increase in glucosinolate content, but when applied in excess had an inhibiting effect.

Rutabaga’s status as a nutritious food has often been overlooked in the United States. Combined with its ease of preparation and possible health benefits, this less glamorous cousin of cabbage and turnips deserves a popularity renaissance.

Nutrient Profile8

Macronutrient Profile: (Per 1 cup raw rutabaga cubes [approx. 140 g])

52 calories
1.5 g protein
12.07 g carbohydrate
0.22 g fat

Secondary Metabolites: (Per 1 cup raw rutabaga cubes [approx. 140 g])

Excellent source of:
Vitamin C: 35 mg (58.3% DV)

Very good source of:
Potassium: 427 mg (12.2% DV)
Dietary Fiber: 3.2 g (12.8% DV)

Good source of:
Manganese: 0.18 mg (9.2% DV)
Thiamin: 0.13 mg (8.7% DV)
Phosphorus: 74 mg (7.4% DV)
Folate: 29 mcg (7.3%DV)
Magnesium: 28 mg (7.0% DV)
Vitamin B6: 0.14 mg (7.0% DV)
Calcium: 60 mg (6.0% DV)

Also provides:
Niacin: 0.98 mg (4.9% DV)
Riboflavin: 0.06 mg (3.5% DV)
Iron: 0.62 mg (3.4% DV)
Vitamin E: 0.42 mg (1.4% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Honey-Lemon Glazed Rutabagas and Carrots

Adapted from: Bon Appétit22

Ingredients:

  • 1 1/4 pounds rutabaga, peeled and sliced into matchstick-sized strips
  • 1 pound carrots, peeled and sliced into matchstick-sized strips
  • 1/4 cup unsalted butter
  • 1/4 cup freshly-squeezed lemon juice
  • 1 teaspoon grated lemon zest
  • 3 tablespoons honey
  • 1/2 cup fresh chives, minced
  • Salt and pepper to taste

Directions:

  1. In a large saucepan, bring lightly salted water to boil. Add rutabagas and cook for 2 minutes. Add carrots and cook until vegetables are tender about 3 minutes. Drain.

  2. Melt butter in a large saucepan over medium-high heat. Add lemon juice, zest, and honey. Bring to a boil.

  3. Add the vegetables and cook until glazed, stirring occasionally about 6 minutes. Season to taste with salt and pepper.

  4. Remove from heat and stir in chives.

References

  1. Van Wyk BE. Food Plants of the World. Portland, OR: Timber Press; 2006.
  2. Davidson A. The Oxford Companion to Food. New York, NY: Oxford University Press; 1999.
  3. Undersander DJ, Kaminski AR, Oelke AE, Doll JD, Schulte EE, Oplinger ES. Rutabaga. Alternative Field Crops Manual. St. Paul, MN: University of Minnesota; Madison, WI: University of Wisconsin; January 1992. Available at: https://hort.purdue.edu/newcrop/afcm/rutabaga.html.
  4. Shields, DS, Spratt S. Rutabaga. American Heritage Vegetable website. Columbia, SC: University of South Carolina. Available at: http://lichen.csd.sc.edu/vegetable/vegetable.php?vegName=Rutabaga.
  5. Onstad D. Whole Foods Companion. White River Junction, VT: Chelsea Green Publishing Company; 2004.
  6. Ensminger AH, Ensminger ME, Konlande JE, Robson JRK. The Concise Encyclopedia of Food and Nutrition. Boca Raton, FL: CRC Press; 1995.
  7. Yepsen R. A Celebration of Heirloom Vegetables. New York, NY: Artisan; 1998.
  8. Full Report (All Nutrients): 11435, Rutabagas, raw. USDA Agricultural Research Service website. Available at: https://ndb.nal.usda.gov/ndb/foods/show/3151. Accessed July 25, 2016.
  9. Mayo Clinic Staff. Dietary fiber: Essential for a healthy diet. Mayo Clinic website. September 22, 2015. Available at: www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fiber/art-20043983. Accessed July 21, 2016.
  10. Anderson JW, Baird P, Davis RH Jr., et al. Health benefits of dietary fiber. Nutrition Reviews. 2009;67(4):188-205.
  11. Ehrlich SD. Potassium. University of Maryland Medical Center. August 5, 2015. Available at:http://umm.edu/health/medical/altmed/supplement/potassium. Accessed July 25, 2016.
  12. Mateljan G. The World’s Healthiest Foods. Seattle, WA: George Mateljan Foundation; 2015.
  13. Bauman H. Food as medicine: broccoli (Brassica oleracea, Brassicaceae). HerbalEGram. March 2016;13:3. Available at:http://cms.herbalgram.org/heg/volume13/03March/FoodAsMedicine_Broccoli.html. Accessed July 25, 2016.
  14. Li H, Tsao R, Deng Z. Factors affecting the antioxidant potential and health benefits of plant foods.Can J Plant Sci. 2012;92:1101-1111.
  15. History of the Jack o’ Lantern. Heritage and History website. October 25, 2011. Available at:http://www.heritageandhistory.com/contents1a/2011/10/history-of-the-jack-o-lantern/. Accessed July 25, 2016.
  16. Game History. The International Rutabaga Curl website. Available at:http://www.rutabagacurl.com/history.html. Accessed July 25, 2016.
  17. Pasko P, Bukowska-Strakova K, Gdula-Argasinska J, Tyszka-Czochara M. Rutabaga (Brassica napus L. var. Napo brassica) seeds, roots, and sprouts: A novel kind of food with antioxidant properties and proapoptotic potential in Hep G2 hepatoma cell line. J Med Food. 2013;16(8):749–759.
  18. Wu YD, Lou YJ. Brassinolide, a plant sterol from the pollen of Brassica napus L., induces apoptosis in human prostate cancer PC-3 cells. Pharmazie. May 2007;62(5):392-395.http://www.ncbi.nlm.nih.gov/pubmed/17557751
  19. Li F, Hullar MAJ, Schwarz Y, Lampe JW. Human gut bacterial communities are altered by the addition of cruciferous vegetables to a controlled fruit and vegetable-free diet. J Nutr. 2009;139:1685-1691.
  20. Tang L, Zirpoli GR, Guru K, et al. Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk. Cancer Epidemiol Biomarkers Prev. 2008;17:938-944.
  21. Sarikamis G. Glucosinolates in crucifers and their potential effects against cancer: Review. Can J Plant Sci. 2009;89:953-959.
  22. Kelley JT. Carrots and Rutabagas with [sic] Lemon and Honey. Bon Appétit. November 1, 2001. Available at: http://www.bonappetit.com/recipe/carrots-and-rutabagas-wtih-lemon-and-honey. Accessed August 3, 2016.