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.

What is Beta-Carotene? What Are The Benefits of Beta-Carotene?

Beta-carotene is a red-orange pigment found in plants and fruits, especially carrots and colorful vegetables.

The name beta-carotene comes from the Greek “beta” and Latin “carota” (carrot). It is the yellow/orange pigment that gives vegetables and fruits their rich colors. H. Wachenroder crystallized beta-carotene from carrot roots in 1831, and came up with the name “carotene”.

Beta-carotene’s chemical formula – C40H56 – was discovered in 1907.

The human body converts beta-carotene into vitamin A (retinol) – beta-carotene is a precursor of vitamin A. We need vitamin A for healthy skin and mucous membranes, our immune system, and good eye health and vision.

Beta-carotene in itself is not an essential nutrient, but vitamin A is.

Fast facts on beta-carotene

Here are some key points about beta-carotene. More detail and supporting information is in the main article.

  • Beta-carotene is a red/orange pigment found in many fresh fruits and vegetables
  • Beta-carotene is converted into vitamin A, an essential vitamin
  • Vitamin A is toxic at high levels
  • Beta-carotene is a carotenoid and an antioxidant
  • Foods rich in vitamin A include onions, carrots, peas, spinach and squash
  • One study showed that smokers with high beta-carotene intake might have an increased risk of lung cancer
  • Some evidence suggests that beta-carotene might slow cognitive decline
  • Beta-carotene supplements interact with certain drugs, including statins and mineral oil
  • Beta-carotene might help older people retain their lung strength as they age.

Beta-carotene from food is a safe source of vitamin A

Vitamin A can be sourced from the food we eat, through beta-carotene, for example, or in supplement form. The advantage of dietary beta-carotene is that the body only converts as much as it needs.

Excess vitamin A is toxic. Toxic vitamin A levels can occur if you consume too many supplements.

Beta-carotene is an antioxidant

A Flamingo
The flamingo’s characteristic red-orange color is caused by beta-carotene in their diet.

Beta-carotene, like all carotenoids, is an antioxidant. An antioxidant is a substance that inhibits the oxidation of other molecules; it protects the body from free radicals.

Free radicals damage cells through oxidation. Eventually, the damage caused by free radicals can cause several chronic illnesses.

Several studies have shown that antioxidants through diet help people’s immune systems, protect against free radicals, and lower the risk of developing cancer and heart disease.

Some studies have suggested that those who consume at least four daily servings of beta-carotene rich fruits and/or vegetables have a lower risk of developing cancer or heart disease.

beta-carotene-foodsWhich foods are rich in beta-carotene?

The following foods are rich in beta-carotene:

  • Apricots
  • Asparagus
  • Broccoli
  • Carrots
  • Chinese cabbage
  • Chives
  • Dandelion leaves
  • Grapefruit
  • Herbs and spices – chili powder, oregano, paprika, parsley
  • Kale
  • Ketchup
  • Many margarines
  • Onions
  • Peas
  • Peppers
  • Plums
  • Pumpkin
  • Spinach
  • Squash
  • Sweet potatoes.

If you follow a healthy diet rich in beta-carotene you do not need supplements. As mentioned above, supplements can lead to undesirable excesses in beta-carotene levels – this cannot occur if your source is from the food you eat.

Smokers and beta-carotene lung cancer risk

A French study involving adult females published in the Journal of the National Cancer Institute (September 2005 issue) found that smokers with high beta-carotene levels had a higher risk of lung cancer and other smoking-related cancers than other smokers. They also found that non-smokers with high beta-carotene intake had a lower risk of lung cancer.

They found that the risk of lung cancer over a ten-year period was:

  • 181.8 per 10,000 women for non-smokers with low beta-carotene intake
  • 81.7 per 10,000 women for non-smokers with high beta-carotene intake
  • 174 per 10,000 women for smokers with low beta-carotene intake
  • 368.3 per 10,000 women for smokers with high beta-carotene intake.

Further research has suggested that the high intake among smokers is nearly always due to supplements, and not food intake.

Beta-carotene may slow down cognitive decline

beta-carrot-juice
Carrots are an excellent source of beta-carotene.

Men who have been taking beta-carotene supplements for 15 or more years are considerably less likely to experience cognitive decline than other males, researchers from Harvard Medical School reported in Archives of Internal Medicine (November 2007 issue).

Oxidative stress is thought to be a key factor in the cognitive decline, the researchers explained. Studies have shown that antioxidant supplements may help prevent the deterioration of cognition.

Their study, involving 4,052 men, compared those on beta-carotene supplements for an average of 18 years to others who were given a placebo. Over the short-term, they found no difference in cognitive decline risk between the two groups of men, but in the long-term, it was clear that beta-carotene supplements made a significant difference.

The researchers emphasized that there may have been other factors which contributed to the slower decline in cognitive abilities among the men in the beta-carotene group.

Beta-carotene drug interactions

Drug interaction refers to a substance interfering in how a medication works, by either making it less effective, increasing its potency, or changing what it is supposed to do.

The following drugs may be affected by beta-carotene supplements:

  • Statins – the effectiveness of simvastatin (Zocor) and niacin may be decreased if the patient is taking beta-carotene with selenium and vitamins E and C.
  • Some cholesterol-lowering drugs – cholestyramine and colestipol can reduce blood levels of dietary beta-carotene by thirty to forty percent.
  • Orlistat (Xenical, Alli) – this is a weight control medication. It can undermine the absorption of beta-carotene by up to 30%, resulting in lower blood beta-carotene levels. Those choosing to take a multivitamin while on orlistat should take them at least two hours before having their medication.
  • Mineral oil – used for the treatment of constipation can lower blood levels of beta-carotene.

Long-term alcohol consumption can interact with beta-carotene, raising the chances of developing liver problems.

Beta-carotene slows down lung power decline as people age

The British Medical Journal published a report in March 2006 which showed that high blood beta-carotene levels compensate for some of the damage to the lungs caused by oxygen free radicals.

They measured the FEV1 of 535 participants and measured their beta-carotene blood levels. FEV1 measures how much air you can breathe out in one go. They found that those with high beta-carotene levels had a much slower decline in FEV1 measures.

Carrots: Health Benefits, Nutritional Information

Carrots are often thought of as the ultimate health food.

You were probably told to “eat your carrots” by your parents and you probably tell your kids the same thing, and when asked why, you explain, “Because they’re good for you!”

But how did the carrot get such a good reputation and why exactly are the root vegetables so good for our health?

It is believed that the carrot was first cultivated in the area now known as Afghanistan thousands of years ago as a small forked purple or yellow root with a woody and bitter flavor, resembling nothing of the carrot we know today.

Purple, red, yellow and white carrots were cultivated long before the appearance of the now popular orange carrot, which was developed and stabilized by Dutch growers in the 16th and 17th centuries.

The modern day carrot has been bred to be sweet, crunchy and aromatic.

Possible health benefits of carrots

An overwhelming body of evidence exists suggesting that increased intake of antioxidant-rich fruits and vegetables reduce cancer and cardiovascular disease risks, carrots included.

Photograph of carrots
Carrots are rich in vitamin A.

Cancer

A variety of dietary carotenoids has been shown to have anti-cancer effects due to their antioxidant power in reducing free radicals in the body.

Lung Cancer

One study found that current smokers who did not consume carrots had three times the risk of developing lung cancer compared with those who ate carrots more than once a week.

Colorectal Cancer

Beta-carotene consumption has been shown to have an inverse association with the development of colon cancer in the Japanese population.

Leukemia

Carrot juice extract was shown to kill leukemia cells and inhibit their progression in a 2011 study.

Prostate Cancer

Among younger men, diets rich in beta-carotene may play a protective role against prostate cancer, according to a study conducted by the Harvard School of Public Health’s Department of Nutrition.

Vision

According to Duke ophthalmologist Jill Koury, MD, vitamin A deficiency causes the outer segments of the eye’s photoreceptors to deteriorate, damaging normal vision. Correcting vitamin A deficiencies with foods high in beta-carotene will restore vision.

Studies have shown that it is unlikely that most people will experience any significant positive changes in their vision from eating carrots unless they have an existing vitamin A deficiency, which is common in developing countries.

So where did all the hype surrounding carrots and vision come from? During World War II, the British Royal Air Force started an advertising campaign claiming that the secret to their fighter pilots clear, the sharp vision was carrots. Realistically, the fighter pilot’s accuracy was due to a new radar system the British wanted to keep secret from the Germans, but the rumor spread and remains popular today.

Other possible benefits of carrots

The antioxidants and phytochemicals in carrots may also help with blood sugar regulation, delay the effects of aging, and improve immune function.

Carrot nutritional breakdown

According to the United States Department of Agriculture, one medium carrot or ½ cup of chopped carrots is considered a serving size. One serving size of carrots provides 25 calories, 6 grams of carbohydrate, 3 grams of sugars and 1 gram of protein.

Carrots are an excellent source of vitamin A, providing 210% of the average adult’s needs for the day. They also provide 6% of vitamin C needs, 2% of calcium needs and 2% of iron needs per serving.

It is the antioxidant beta-carotene that gives carrots their bright orange color. Beta-carotene is absorbed in the intestine and converted into vitamin A during digestion.

Carrots also contain fiber, vitamin K, potassium, folate, manganese, phosphorous, magnesium, vitamin E, and zinc.

carrots-rainbowFarmer’s markets and some specialty stores carry carrots in a range of colors – like purple, yellow, and red – that contain a variety of antioxidants lending them their color (such as anthocyanin in purple carrots and lycopene in red carrots).

Incorporating carrots into your diet

Carrots can be found in supermarket year-round, but are available locally during their bi-annual seasons in the spring and fall. They are a versatile vegetable and commonly eaten raw, steamed, boiled, roasted and as an ingredient in many soups and stews. They can be bought fresh, frozen, canned or even pickled.

Carrots are best stored in the refrigerator in a sealed plastic bag. If the greens are still attached to the top of the carrot, remove them before storing to prevent the greens from drawing out moisture and nutrients from the roots. Carrots should be peeled and washed before consuming.

Shredded carrots can be used in coleslaw, on salads, in wraps or as an ingredient in baked goods such as cakes and muffins due to their sweet flavor.

Carrot sticks or baby carrots make for a great snack and are often a popular vessel for herbed dips and hummus and on variety vegetable trays.

Carrots are a popular vegetable to juice because of their sweet mild flavor.

Eating carrots raw or steamed provides the most nutritional value.

Carrot precautions

Overconsumption of vitamin A can be toxic to humans but is unlikely to be achieved through diet alone (most vitamin overconsumption occurs by supplementation).

Overconsumption of carotene may cause a slight orange tinge in skin color but is not harmful to health.