Carrots were not always orange. Carrots domesticated in the East were often purple or yellow, and a 2023 genome study of 630 carrot samples concluded that orange carrots were selected during the Renaissance, probably in western Europe. The popular tale that Dutch growers made them orange to honor William of Orange has little evidence behind it beyond oral tradition.
The orange comes from carotenoids. On this site, raw carrots have 8,285 µg of beta-carotene and 3,477 µg of alpha-carotene per 100 g, and 100 g covers 93% of the daily value of vitamin A. Your body does not turn all of it into vitamin A: in a study of 7 men, it took about 15 units of carrot beta-carotene by weight to make 1 unit of vitamin A.
The night vision story is a myth. In World War II, British pilots such as John “Cat’s Eyes” Cunningham were said to shoot down night bombers because they ate carrots, but the real edge was airborne radar. A curator of the World Carrot Museum, who studied wartime files, says the Ministry of Information spread the carrot story to hide the radar, while an RAF Museum curator says Britain never set out to fool the Germans with it. One part is true: a lack of vitamin A causes night blindness, and in a trial in Nepal, carrots corrected it in pregnant women.
Health benefits of carrots
The top findings from 30 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Beta-carotene pills raised lung cancer riskThese were pills, not carrots. Across 31 trials lung cancer deaths rose by 14%, and lung cancer rose by 18% in male smokers taking 20 mg a day.
- ★Restored dark vision in night-blind pregnant womenIn Nepal, night-blind pregnant women who ate carrots daily for 6 weeks regained dark vision as well as those taking a vitamin A supplement. It shows carrots can fix a shortage, not sharpen normal eyes.
- ★More beta-carotene absorbed with fat or cookingIn small studies of healthy adults, stir-frying raised usable beta-carotene from about 11% to 75% of the pure compound. Eating raw carrots with avocado raised beta-carotene absorption 6.6-fold.
- ★Lower cholesterol in one early studyEating 200 g of raw carrot a day for 3 weeks lowered blood cholesterol by 11%. It is a 1979 study with little detail, so treat it as a lead.
- ★Less DNA damage in smokers’ white blood cellsOf 48 Korean smokers, the 18 on 300 mL of carrot juice a day for 8 weeks had less DNA damage in white blood cells. That is a lab marker, not a disease.
All 30 studies, strongest evidence first
Beta-carotene supplements raised lung cancer deaths by 14% and did not lower overall deaths across 31 trials
Meta-analysis of 31 randomized trials with 216,734 people that compared beta-carotene pills at any dose with placebo or no treatment. Overall risk of death was unchanged (risk ratio 1.02), while HIV-related deaths were lower (risk ratio 0.55). These were pills, not carrots, and the authors say the findings must not be overstated.
20 mg a day of beta-carotene pills for 5 to 8 years raised lung cancer by 18% in male smokers
Double-blind, placebo-controlled trial in 29,133 Finnish men aged 50 to 69 who smoked. Total deaths were 8% higher with beta-carotene, mainly from lung cancer and ischemic heart disease. The authors called the result unexpected, and it came from a pill, not from food.
30 mg a day of beta-carotene plus vitamin A raised lung cancer risk by 28% in smokers and asbestos-exposed workers
Double-blind, placebo-controlled trial in 18,314 smokers, former smokers and asbestos-exposed workers, who took 30 mg of beta-carotene with 25,000 IU of retinol a day. After an average of 4 years, death from any cause was 17% higher and the trial was stopped 21 months early. The pill combined two compounds, so the harm cannot be pinned on beta-carotene alone.
Eating carrots daily for 6 weeks restored dark vision in night-blind pregnant women as well as a vitamin A supplement did
Randomized trial in Nepal, where night blindness is common in pregnancy. Night-blind women received 850 µg of vitamin A equivalents a day, 6 days a week, as carrots, amaranth leaves, goat liver, fortified rice or retinyl palmitate. Dark adaptation improved to the level of women without night blindness, and carrots did not differ significantly from the supplement. It shows carrots can fix a shortage, not that they sharpen normal eyes, and the abstract gives no group sizes.
200 g of raw carrot a day for 3 weeks lowered serum cholesterol by 11%
Early study from 1979. Fecal bile acid and fat excretion rose by 50% and stool weight by 25%, and the changes in cholesterol, bile acids and fat were still there 3 weeks after stopping. The abstract does not give the number of people or say whether a control group was used, so treat it as a lead, not proof.
Stir-frying carrots raised beta-carotene bioavailability from about 11% to 75% of the pure compound
Small group of healthy adults who ate 100 g portions of carrots grown with a heavy-hydrogen tracer, raw or stir-fried, so absorption could be followed in blood. Combining absorption and conversion, the vitamin A yield was 6.5 times higher from stir-fried carrots. The authors link the gain to the fat in the meal.
Eating raw carrots with avocado raised beta-carotene absorption 6.6-fold
Randomized crossover trial in 12 healthy adults who ate raw carrots (27.3 mg of beta-carotene and 18.7 mg of alpha-carotene) with or without avocado, which gave 23 g of fat. Alpha-carotene absorption rose 4.8-fold and conversion to vitamin A 12.6-fold. A separate 12-person study of tomato sauce found a 2.4-fold boost.
Fresh carrot juice gave about twice the beta-carotene absorption of raw carrots
Randomized crossover trial in 16 healthy adults who consumed 25 mg of beta-carotene as raw carrots or fresh juice. Peak blood levels were 2.33 times higher with juice and the total absorbed over 24 hours was 2.09 times higher, while alpha-carotene did not differ significantly. It measured absorption of one pigment, not health outcomes.
Puréed carrots gave 1 unit of vitamin A for every 15 units of beta-carotene, against 21 for spinach
Seven men ate 100 g of puréed carrots grown with a heavy-hydrogen tracer, so the beta-carotene could be followed in blood, and the result was compared with a vitamin A reference dose. The ratio was 14.8 to 1 by weight for carrots (range 7.7 to 24.5) and 20.9 to 1 for spinach. The authors say these vegetables supply less vitamin A than once proposed, but still a significant amount.
In mixed meals, raw carrots gave lower blood sugar and insulin responses than microwaved carrots
Study in 10 healthy men who ate meals with carrots that were raw, blanched and frozen, thawed, boiled or microwaved. Satiety scores were higher with raw carrots in the first year, but in the second year, with more fiber from carrots, only the glucose response differed. The authors judge the effect of cooking minor in ordinary meals.
16 fl oz of fresh carrot juice a day for 3 months raised antioxidant capacity and lowered a lipid damage marker
Pilot study in adults who kept their usual diets. Cholesterol, triglycerides, LDL, HDL, insulin, leptin and CRP did not change, and the drop in systolic blood pressure just missed significance (P = 0.06). The abstract does not give the number of people.
8 oz of fresh carrot juice a day for 3 weeks raised plasma carotenoids by 1.4 to 1.7 µmol/L
Randomized trial in 69 overweight breast cancer survivors who drank juice from one of two carrot varieties. A bigger rise in carotenoids went with lower oxidative stress, but inflammation markers did not change. No placebo group is described, and it measured blood markers, not cancer recurrence.
300 mL of carrot juice a day for 8 weeks lowered DNA damage in the white blood cells of smokers
Randomized placebo-controlled trial in 48 Korean smokers: 18 drank carrot juice, 16 took a beta-carotene capsule (about 20 mg of beta-carotene a day in both) and 14 took placebo. Purified beta-carotene lowered DNA damage too, and neither changed blood fats. DNA damage in lymphocytes is a lab marker, not a disease.
330 mL of carrot juice a day for 2 weeks changed only a few colon cancer markers in healthy men
Randomized crossover trial in 22 young men on a low-carotenoid diet, with stool analyzed in 12. Carrot juice raised beta- and alpha-carotene in stool and lowered stool water pH, but bile acids and bacterial enzyme activity did not change. The authors call the effects minor.
272 g of cooked carrots a day for 42 days did not turn skin orange, but 30 mg beta-carotene pills did
Trial in 30 men, 5 in each of six groups: carrots, broccoli, tomato juice, two doses of beta-carotene pills or placebo. Definite orange skin (carotenodermia) showed up only in the five men on 30 mg pills, and only after total blood carotenoids passed 4.0 mg/L. The groups were very small.
Lutein from yellow carrots was 65% as bioavailable as lutein from a supplement
Randomized, blinded crossover trial in 9 adults who ate bred yellow carrots (1.7 mg of lutein a day), white carrots as a control, or a lutein supplement, for 7 days each. Lutein is the pigment of the macula in the eye, but the study measured blood levels, not eye health. These were a bred variety, not common orange carrots.
People who ate the most carrots had a 10% lower risk of cancer in a pool of 50 prospective studies
Meta-analysis of prospective observational studies: 50 on carrot intake (52,000 cancer cases, risk ratio 0.90) and 30 on blood alpha-carotene (9,331 cases, risk ratio 0.80), with moderate differences between studies. Alpha-carotene was used as a stand-in for carrot intake. It shows a link, not proof, since carrot eaters may live differently.
Adults who ate the most carrots had 42% lower odds of lung cancer across 18 studies
Meta-analysis of 17 case-control studies and 1 cohort study with 202,969 people and 5,517 lung cancer patients (odds ratio 0.58). The link was clearest for adenocarcinoma (odds ratio 0.34), while several other subtypes were not significant. Case-control studies rely on recalled diets, and smoking habits can blur the link.
Eating raw carrots 2 to 4 times a week went with a 17% lower risk of colorectal cancer
Prospective cohort of 57,053 Danes followed for more than 18 years. The drop (hazard ratio 0.83) was for more than 32 g a day compared with no raw carrots, and eating less than that was not significantly linked to lower risk. Intake was self-reported once, at the start.
The highest carrot intake went with 21% lower odds of breast cancer in 10 studies
Meta-analysis of 10 articles with 13,747 cases (odds ratio 0.79). The link was stronger in case-control studies than in cohort studies, and results varied a lot between studies.
The highest carrot intake went with 18% lower odds of prostate cancer
Meta-analysis (odds ratio 0.82). Each extra serving a week, or 10 g a day, went with a 5% or 4% lower risk. The authors note few cohort studies and substantial differences between studies, and ask for better-designed prospective studies.
The highest carrot intake went with 37% lower odds of urothelial cancer
Meta-analysis of 4 case-control and 2 cohort studies on cancers of the bladder and urinary tract lining (odds ratio 0.63). Results differed widely between studies, and the authors call for large prospective cohorts.
The highest carrot intake went with 26% lower odds of stomach cancer
Meta-analysis of 5 articles using a fixed-effects model (odds ratio 0.74), a small pool. The abstract does not say how many people took part or how the studies were designed.
Carrot intake showed no link with bladder cancer risk in 99,650 Americans
Prospective cohort from the PLCO screening trial, followed for a median of 12.5 years, with 762 bladder cancers. Highest against lowest intake gave a hazard ratio of 0.96 (95% CI 0.76 to 1.22), and a pooled analysis with two earlier cohorts gave 1.02. This differs from the urothelial pool above.
Adults with the highest blood alpha-carotene had a 39% lower risk of death over follow-up
US national survey (NHANES III follow-up) of 15,318 adults. Alpha-carotene is a pigment that carrots are especially rich in, and the link held for deaths from heart disease, cancer and other causes. Blood levels also reflect other vegetables and lifestyle, so this is a link, not proof.
Women who ate carrots more than twice a week had 64% lower odds of glaucoma
Cross-sectional study of 1,155 older American women, 95 of whom had glaucoma (odds ratio 0.36 against under one serving a week). Collards and kale, and canned or dried peaches, also stood out among the foods tested. A single food questionnaire cannot show that carrots came first, and the authors ask for more studies.
Women who ate more carrots reported more, not less, poor night vision
Blue Mountains Eye Study, an Australian survey of older people who rated their night vision and filled in a food questionnaire. Among women, poor night vision also went with higher beta-carotene and vitamin A intake, and carrots were the only beta-carotene food with this link. The authors suspect people who struggle to see at night eat more carrots hoping to fix it.
Falcarinol and falcarindiol, two compounds from carrots, cut colon tumors in rats from 15 of 20 to 8 of 20
Forty rats were given a cancer-causing chemical, and half also ate feed with 7 µg per gram of each compound for 18 weeks. Small early lesions also fell (median 145 against 218). These were purified compounds fed to rats, not carrots eaten by people.
Rats fed a diet with 15% carrot had 44% less cholesterol in the liver
Rats on a cholesterol-rich diet got carrot (15% of dry matter) for 3 weeks. Cholesterol absorption fell, bile acids were still secreted and markers of antioxidant status improved. Animal results often do not carry over to people.
Mice on a high-fat diet with 10% carrot powder had better glucose tolerance after 16 weeks
Mouse model of type 2 diabetes. Gut bacteria in the cecum became more diverse, but gene activity in fat and muscle did not change. Mice are not people, and the effect is not shown here in people.
Who should be careful with carrots
Most people can eat carrots freely. Take a little care if one of these applies:
- Beta-carotene pills and smoking. Two large trials found more lung cancer in smokers and asbestos-exposed workers who took beta-carotene pills (18% more in one, 28% more in the other, which also gave vitamin A). Studies of eating carrots have not shown this harm.
- Birch pollen or carrot allergy. Carrot is a frequent cause of food allergy in Europe, and in a Swiss food-challenge study the reactions traced to proteins related to birch pollen allergens. If raw carrot makes your mouth or throat itch, ask an allergist, because allergic reactions can be serious.
- Orange skin. Very large amounts over weeks can tint skin yellow-orange, called carotenemia. It is benign, though doctors sometimes mistake it for jaundice, and 272 g of cooked carrots a day for 42 days did not cause it in one trial.
How to choose, store and eat carrots
- Raw: the beta-carotene is harder to absorb, at about 11% of a pure dose in one small study.
- Cooked with fat: stir-frying raised that to 75%, and raw carrots eaten with avocado raised beta-carotene absorption 6.6-fold.
- Juice: fresh juice gave about twice the beta-carotene absorption of raw carrots in 16 adults.
Pick firm, deep-colored carrots without soft spots or splits, cut off any green tops, and keep them in a plastic bag in the fridge for up to two weeks. Scrub off dirt and rinse before eating. Residues are no reason to skip carrots: in USDA tests of 708 carrot samples in 2021, none had a residue above the legal limit.
Sources
- Ballmer-Weber BK, Wüthrich B, Wangorsch A, et al. Carrot allergy: double-blinded, placebo-controlled food challenge and identification of allergens. J Allergy Clin Immunol. 2001.
- Ballmer-Weber BK, Skamstrup Hansen K, Sastre J, et al. Component-resolved in vitro diagnosis of carrot allergy in three different regions of Europe. Allergy. 2012.
- Al Nasser Y, Jamal Z, Albugeaey M. Carotenemia. StatPearls. 2023.
- Micozzi MS, Brown ED, Taylor PR, Wolfe E. Carotenodermia in men with elevated carotenoid intake from foods and beta-carotene supplements. Am J Clin Nutr. 1988.
- Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med. 1994.
- Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996.
- Ghavami A, Coward WA, Bluck LJ. The effect of food preparation on the bioavailability of carotenoids from carrots using intrinsic labelling. Br J Nutr. 2012.
- Kopec RE, Cooperstone JL, Schweiggert RM, et al. Avocado consumption enhances human postprandial provitamin A absorption and conversion from a novel high-β-carotene tomato sauce and from carrots. J Nutr. 2014.
- Choi M, Baek J, Park E. Comparative bioavailability of β-carotene from raw carrots and fresh carrot juice in humans: a crossover study. Nutr Res Pract. 2025.
- Carrots. University of Nebraska–Lincoln Extension.
- Pesticide Data Program annual summary, calendar year 2021. USDA Agricultural Marketing Service.
History of carrots
People first grew carrot plants for their leaves and seeds, not the root. Carrot seeds have turned up in Swiss and southern German sites dating to 2000 to 3000 BC. The Romans ate a root called pastinaca that may have been carrot or parsnip, and a 6th-century copy of a Greek herbal says the root can be cooked and eaten.
The root we know came later. The 2023 genome study concluded that carrot was domesticated in the Early Middle Ages in a region from western to central Asia, and an earlier study found that wild carrots from Central Asia were genetically closest to cultivated ones. In the 11th and 12th centuries, a Jewish scholar and an Arab-Andalusian farmer both wrote of red and yellow carrots.
Orange came last. Orange carrots probably became a stable type only when Dutch growers bred “Long Orange” around the start of the 18th century, and the tale of honoring William of Orange has little support. One suggestion is that Europeans liked orange because it does not brown soups and stews the way purple does.
Carrots then traveled the world. Cultivated carrots appeared in China in the 12th century and in Japan in the 16th or 17th century, and European settlers brought them to colonial America in the 17th century. In 2024, world production of carrots, counted together with turnips, was about 45 million tonnes, and China grew 42% of it.
Britain leaned hard on carrots in World War II. The Dig for Victory campaign urged families to grow vegetables, the BBC radio show The Kitchen Front shared recipes, and a cartoon “Doctor Carrot” appeared on posters and in newspaper ads. By 1942 the country had a 100,000-ton carrot surplus, and cooks used carrots as a sweetener in pudding, cake and marmalade while sugar was rationed at 8 ounces per adult a week.
Sources
- Coe K, Bostan H, Rolling W, et al. Population genomics identifies genetic signatures of carrot domestication and improvement and uncovers the origin of high-carotenoid orange carrots. Nat Plants. 2023.
- Iorizzo M, Senalik DA, Ellison SL, et al. Genetic structure and domestication of carrot (Daucus carota subsp. sativus) (Apiaceae). Am J Bot. 2013.
- Carrot. Wikipedia.
- A WWII propaganda campaign popularized the myth that carrots help you see in the dark. Smithsonian Magazine.
- Haskell MJ, Pandey P, Graham JM, et al. Recovery from impaired dark adaptation in nightblind pregnant Nepali women who receive small daily doses of vitamin A as amaranth leaves, carrots, goat liver, vitamin A-fortified rice, or retinyl palmitate. Am J Clin Nutr. 2005.
- Vitamin A deficiency. World Health Organization.
Frequently asked questions about carrots
Are carrots good for you?
For most people, yes. Raw carrots have 835 µg of vitamin A (RAE), 93% of the daily value, and 2.8 g of fiber for 41 calories per 100 g. A pool of 50 prospective studies linked the highest carrot intake to a 10% lower cancer risk, but that is a link, not proof, and no carrot finding here reaches strong evidence. The best-tested fact is vitamin A: carrots restored dark vision in night-blind pregnant women.
Do carrots improve eyesight or night vision?
Only if you were short of vitamin A. In night-blind pregnant women in Nepal, carrots restored dark vision as well as a vitamin A supplement, but in older Australians more carrots went with more reports of poor night vision in women. In a US study of older women, those who ate carrots more than twice a week had 64% lower odds of glaucoma, though that is a one-time questionnaire link. Nothing here shows carrots sharpen healthy eyes.
Are raw or cooked carrots healthier?
Neither is simply better. In one small study, stir-frying raised beta-carotene bioavailability from about 11% to 75% of a pure dose, and raw carrots eaten with avocado raised absorption 6.6-fold in 12 adults. On the other hand, in 10 men raw carrots gave lower blood sugar and insulin responses than microwaved ones. Cooking with a little fat is a good habit for the carotene.
How many carrots can you eat a day?
No study here sets an ideal amount. In a Danish cohort, eating raw carrots 2 to 4 times a week (more than 32 g a day) went with a 17% lower risk of colorectal cancer. Trials used 200 g of raw carrot a day for 3 weeks and 272 g of cooked carrots a day for 42 days. One medium carrot (61 g) has 25 calories and 57% of the daily value of vitamin A.
Can eating too many carrots turn your skin orange?
It can, but it takes a lot and it is benign. Carotenemia is yellow-orange skin from high blood carotene, and doctors sometimes mistake it for jaundice. In a 42-day trial, 272 g of cooked carrots a day did not cause definite orange skin, while 30 mg beta-carotene pills did. In a review of about 100 cases linked to high beta-carotene intake, the color lasted from 14 days to 4.5 years.
Are carrots high in sugar?
Not especially. Raw carrots have about 4.7 g of sugars and 2.8 g of fiber per 100 g, and an estimated glycemic index of 32. In 10 men, raw carrots gave lower blood sugar responses than microwaved ones in a mixed meal, and carrot powder improved glucose tolerance in mice on a high-fat diet. Neither has been shown in people with diabetes here, so check portions with your care team.
Are carrots good for weight loss?
No study here tested weight loss. Carrots have 41 calories and 2.8 g of fiber per 100 g, so a medium carrot (61 g) is only 25 calories and fills a plate cheaply. That is a swap effect for higher-calorie foods, not a proven effect of carrots themselves.
Is carrot juice better than eating carrots?
It depends on the goal. Fresh juice gave about twice the beta-carotene absorption of raw carrots in 16 adults, and 16 fl oz a day for 3 months raised antioxidant capacity in a pilot study. No trial here compared health outcomes of juice with whole carrots, and juice did not change cholesterol or CRP in that pilot.