Vitamins & Supplements · Antioxidant
Beta-carotene
Beta-carotene (C40H56) · also called Carotene, provitamin A
Beta-carotene is the orange-yellow pigment in carrots, sweet potatoes and leafy greens. The body turns it into vitamin A. Food is the natural source. Large trials found that beta-carotene pills raised lung cancer risk in smokers and asbestos-exposed workers and showed no cancer or heart benefit, so smokers should ask a doctor before any product that contains it.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Beta-carotene
Beta-carotene is the orange-yellow pigment in carrots, sweet potatoes and leafy greens, and the body turns it into vitamin A. Pills are a different matter from food: two large trials found it raised lung cancer risk in smokers and asbestos-exposed workers.
What beta-carotene is
Beta-carotene is a carotenoid, a plant pigment. MedlinePlus says it is the most common provitamin A, which means the body converts it into vitamin A after it is eaten. Vitamin A helps vision in dim light and keeps the skin, mucous membranes and immune system healthy. There are more than 500 known carotenoids.
Beta-carotene is also sold as a supplement, alone or in multivitamins and eye formulas. It is not the same as preformed vitamin A (retinol) from animal foods and supplements, which can cause serious illness in large amounts. Large amounts of beta-carotene do not do that, but can turn the skin yellow or orange (MedlinePlus).
Where beta-carotene comes from in food
Orange, yellow and dark green plants are the main sources. USDA data (per portion): baked sweet potato, 1 cup, about 23.0 mg; cooked spinach, 1 cup, about 11.3 mg; cooked carrots, half a cup, about 6.5 mg; cantaloupe cubes, 1 cup, about 3.2 mg; cooked kale, 1 cup, about 2.0 mg; mango pieces, 1 cup, about 1.1 mg; one apricot about 0.38 mg.
MedlinePlus says the deeper or brighter the colour, the more carotenoids, and that beta-carotene is absorbed better when the food is eaten with a small amount of fat. These are nutrient amounts in foods, not advice.
The ATBC and CARET trials
Because people who ate more colourful plants had less lung cancer, researchers tested beta-carotene pills in people at high risk. In the Finnish ATBC trial (29,133 male smokers, 5 to 8 years), lung cancer was 18% more common with beta-carotene and total deaths were 8% higher. In the US CARET trial (18,314 smokers, former smokers and asbestos workers), a pill with beta-carotene and vitamin A raised lung cancer risk by 28% and the trial was stopped 21 months early.
The Physicians' Health Study (22,071 male doctors, about 12 years) and the Women's Health Study (39,876 women) found neither benefit nor harm for cancer and heart disease overall. In AREDS2, more lung cancers occurred with beta-carotene, mostly in former smokers.
What the combined reviews say
A 2010 meta-analysis of 9 trials found no effect of beta-carotene pills on all cancers, but more lung cancer (relative risk 1.16) and stomach cancer (1.34) at 20 to 30 mg a day, and larger rises in smokers and asbestos workers. A 2012 Cochrane review of 78 antioxidant trials found beta-carotene was linked with slightly more deaths in better-quality trials (relative risk 1.05).
In 2022 the US Preventive Services Task Force concluded with moderate certainty that the harms of beta-carotene supplements outweigh the benefits for preventing heart disease or cancer, and recommends against them. NCCIH says the same of high doses in smokers and asbestos-exposed people.
The eye formula story
The original AREDS eye formula contained beta-carotene along with vitamins C and E, zinc and copper. It lowered the odds of advanced macular degeneration in people who already had signs of it (odds ratio 0.72), and a 2023 Cochrane review rates this as moderate-certainty. AREDS2 then tested the formula without beta-carotene, and found no apparent change in how well it worked.
The National Eye Institute says current and former smokers should use the AREDS2 formula, which has lutein and zeaxanthin instead of beta-carotene. Beta-carotene pills did not prevent cataract in a Cochrane review of 9 trials. People with macular degeneration should ask an eye doctor about any formula.
Did the harm last?
After ATBC ended, the extra risk of death was no longer evident 4 to 6 years later, and an 18-year follow-up found no late effect on lung cancer or total deaths, though prostate cancer deaths were higher with beta-carotene. In CARET, lung cancer and death risks stayed above 1.0 after stopping but were no longer statistically significant. The ATBC authors still conclude that smokers should avoid beta-carotene supplements.
Food versus pills
MedlinePlus says eating food sources of beta-carotene may reduce cancer risk, but supplements do not and may raise it in smokers. NCCIH says purified antioxidants in pills may act differently from the smaller amounts in food. No trial compared the two directly. This page gives no amounts to take; if you wonder about your own needs, ask a doctor, pharmacist or dietitian.
At a glance
Traditional uses history, not proof
- A pigment and vitamin A source in colourful vegetables and fruit
- Sold as antioxidant pills, in multivitamins and in eye formulas
Studied for research
- Source of vitamin A, high certainty
- Cancer prevention, evidence against (more lung cancer in smokers)
- Deaths and heart disease, evidence against
- Macular degeneration (as part of the AREDS formula), moderate certainty
- Cataract, evidence against
- Thinking and memory, low certainty
Main compounds
- Beta-carotene
- Retinyl palmitate (given with it in the CARET trial)
- Lutein and zeaxanthin (replaced it in the AREDS2 formula)
Common forms
- Food sources (sweet potato, spinach, carrots, cantaloupe, kale, mango)
- Stand-alone beta-carotene capsules
- Multivitamins and eye formulas that contain it
Research links: 1994 ATBC trial: vitamin E and beta-carotene in male smokers · 1996 CARET trial: beta-carotene and vitamin A in smokers and asbestos workers · 2010 meta-analysis: beta-carotene supplements and cancer risk · 2022 USPSTF recommendation on vitamin and mineral supplements · 2013 AREDS2 trial: eye formula with and without beta-carotene · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Beta-carotene (a provitamin A carotenoid; plant pigment)
- Common names
- Beta-carotene (English); Carotene (English); Provitamin A (English); Betacaroteno (Spanish)
- Family or group
- Carotenoid (plant pigment). MedlinePlus says there are more than 500 known carotenoids and that beta-carotene is the most common provitamin A.
- Look-alikes and adulterants
- Name: Vitamin A (retinol, retinyl palmitate); Note: Preformed vitamin A from animal foods and some supplements. Different from beta-carotene: large amounts can cause serious illness and birth defects (MedlinePlus). It has its own page.; Name: Lutein and zeaxanthin; Note: Other carotenoids. Used in the AREDS2 eye formula in place of beta-carotene (NEI).
- Sustainability and conservation
- Not assessed.
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| 1994 to 1996 prevention trials | The ATBC (Finland, 1994) and CARET (USA, 1996) trials tested beta-carotene pills for preventing lung cancer. Both found more lung cancer with the pills; CARET was stopped 21 months early. The Physicians' Health Study (1996) found neither benefit nor harm in mostly healthy male doctors. | p8127329; p8602180; p8602179 |
| AREDS eye studies, 2001 and 2013 | The original AREDS formula included beta-carotene and lowered the odds of advanced macular degeneration. The AREDS2 trial (2006 to 2012) tested taking beta-carotene out and replacing it with lutein and zeaxanthin because of the lung cancer finding in smokers. | p11594942; p23644932; s-nei-areds |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Beta-carotene PubChem 5280489 | carotenoid (tetraterpene hydrocarbon) | Orange, yellow and dark green fruit and vegetables (carrots, sweet potatoes, spinach, mango, cantaloupe) See the food values from USDA in the Benefits tab and nutrition note. | Provitamin A: converted to vitamin A in the body; antioxidant in the laboratory. 17 20 18 | Human data |
| Retinyl palmitate (with beta-carotene in CARET) | preformed vitamin A ester | Trial amount in CARET: 25,000 IU a day (not advice). | A vitamin A form given together with beta-carotene in CARET. 13 17 | Human data |
| Lutein and zeaxanthin | carotenoids | Not read from a source. | Carotenoids found in the eye; used in the AREDS2 formula in place of beta-carotene. 19 1 | Human data |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Conversion to vitamin A | Not specified in the sources read | After eating, the body converts beta-carotene to vitamin A (retinol). Vitamin A is needed for dim-light vision, skin, mucous membranes and the immune system. 17 20 | Human data |
| Antioxidant activity | Not specified in the sources read | Beta-carotene is grouped with antioxidants, which can neutralise reactive molecules in the lab. NCCIH says purified antioxidants in supplements may act differently from those in foods. 18 | Laboratory research |
| Why pills raised lung cancer risk | Not specified in the sources read | Not established. The trial abstracts report the risk but do not explain how it arises. 3 13 | Unknown |
Absorption, metabolism and elimination
- Absorption
- MedlinePlus says absorption of beta-carotene from vegetables is improved when the food is eaten with a small amount of fat. Detailed absorption data for supplements were not read.
- Distribution
- Not described in the sources read.
- Metabolism
- The body converts beta-carotene to vitamin A (MedlinePlus, NHS).
- Elimination
- Not described in the sources read.
- Bioavailability
- Not compared between food and supplements in the sources read.
Isolated compounds versus whole extracts
Beta-carotene from colourful food and beta-carotene pills are not the same thing. Food brings fibre, other carotenoids and plant compounds, and the amounts are smaller. MedlinePlus says eating food sources of beta-carotene may reduce cancer risk while supplements do not and may raise risk in smokers and asbestos workers. NCCIH says pills do not reproduce the benefits seen with fruit-and-vegetable diets. No trial compared the two.
Nutritional composition
Beta-carotene content of foods is from USDA FoodData Central SR Legacy (April 2018), read from a saved local copy: sweet potato baked in skin about 23.0 mg per cup, spinach cooked about 11.3 mg per cup, carrots cooked about 6.5 mg per half cup, cantaloupe about 3.2 mg per cup of cubes, kale cooked about 2.0 mg per cup, mango about 1.1 mg per cup of pieces, apricot about 0.38 mg each. Values vary between samples.
2 high certainty1 moderate certainty2 low certainty1 not enough evidence4 evidence against
What was looked at
The 10 benefits and uses checked for Beta-carotene, each with how strong the evidence is. Tap one to open it.
- Source of vitamin A (provitamin A)High certainty
- Food sources of beta-caroteneHigh certainty
- Lung cancer in smokers and asbestos-exposed workers (a harm, not a benefit)Evidence against
- Cancer prevention in people who are not at high riskEvidence against
- Deaths and heart diseaseEvidence against
- Age-related macular degeneration (as part of the AREDS formula)Moderate certainty
- CataractEvidence against
- Thinking and memoryLow certainty
- Colourful fruit and vegetables versus beta-carotene pillsLow certainty
- Antioxidant activity in the labNot enough evidence
Lab markers tracked in the studies
Lung cancer casesDeaths from any causeAny cancer (all types)Progression to advanced AMDYellowing of the skin (hypercarotenodermia)
What is Beta-carotene good for?
The main studied uses and how strong the human evidence is for each. For beta-carotene pills the trials found no benefit for prevention and some harm in smokers, so read each certainty label carefully.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Source of vitamin A (provitamin A)
High certaintyBeta-carotene is an orange-yellow plant pigment that the body converts into vitamin A. Vitamin A helps vision in dim light and keeps the skin, the lining of the nose and mouth, and the immune system healthy. Both MedlinePlus and the NHS say you can get vitamin A from beta-carotene in food. Neither says beta-carotene pills are needed.
2 studiesBeta-carotene from food and from supplements; forms are not compared …
Studies, doses and limits
What the trials found
MedlinePlus says vitamin A is found as preformed retinol (animal foods) and as provitamin A carotenoids from plants, and that beta-carotene is the most common provitamin A. It lists the roles of vitamin A: teeth, skeletal and soft tissue, mucous membranes and skin, and eyesight especially in low light. Deficiency causes reversible night blindness, and in severe cases lasting damage to the front of the eye. The NHS lists the immune system, dim-light vision and healthy skin and nose lining, and says a varied diet should provide all the vitamin A needed. No trial was read showing that beta-carotene pills help people who already get enough vitamin A.
Results
Beta-carotene is a useful food source of vitamin A. Eating it in food is the usual route. No source read says pills are needed, and the same pills raised lung cancer risk in smokers (see Safety).
Effect sizes as reported
No effect sizes apply: these are nutrient roles, not trial results.
Why this rating
High that the body converts beta-carotene to vitamin A and that vitamin A is essential (MedlinePlus, NHS). This is a statement about the nutrient from food, not a trial result for the pills.
Form and dose studied
Beta-carotene from food and from supplements; forms are not compared here.
Who was studied
General population; people short of vitamin A are the group in whom a source of vitamin A matters most.
Limits
Role statements come from health reference pages, not trials.
Why researchers looked
People ask whether they get enough vitamin A, and whether a pill is a better source than food.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Established nutrition
The body converts beta-carotene to vitamin A (retinol) after it is eaten. This is established physiology described by MedlinePlus and the NHS.
A proposed mechanism does not show that the effect happens in people.
Pills have raised lung cancer risk in smokers; see the Safety tab.
Food sources of beta-carotene
High certaintyBeta-carotene gives orange, yellow and dark green foods their colour. By USDA data, one cup of baked sweet potato has about 23 mg, a cup of cooked spinach about 11 mg, half a cup of cooked carrots about 6.5 mg, a cup of cantaloupe cubes about 3.2 mg, a cup of cooked kale about 2.0 mg and a cup of mango pieces about 1.1 mg. The body takes it up better when the food is eaten with a little fat.
3 studiesBeta-carotene as it occurs in plant foods.
Studies, doses and limits
What the trials found
MedlinePlus names carrots, sweet potatoes, mangos, cantaloupe, broccoli, spinach and most dark green leafy vegetables as sources, says the deeper or brighter the colour the more carotenoids, and that absorption is better with a small amount of fat. The NHS names spinach, carrots, sweet potatoes, red peppers, mango, papaya and apricots. No trial was read comparing beta-carotene from food with pills for health results.
Results
Colourful vegetables and fruit are the natural source. Amounts vary with the variety, ripeness and cooking, so USDA values are typical figures, not exact.
Effect sizes as reported
USDA beta-carotene per 100 g and per portion: carrots cooked 8,332 micrograms (half a cup, 78 g, about 6.5 mg); sweet potato baked in skin 11,509 micrograms (1 cup, 200 g, about 23.0 mg); spinach cooked 6,288 micrograms (1 cup, 180 g, about 11.3 mg); cantaloupe raw 2,020 micrograms (1 cup cubes, 160 g, about 3.2 mg); kale cooked 1,731 micrograms (1 cup, 118 g, about 2.0 mg); mango raw 640 micrograms (1 cup pieces, 165 g, about 1.1 mg); apricot raw 1,094 micrograms (1 apricot, 35 g, about 0.38 mg).
Why this rating
High: these are database values for the foods listed, plus consistent statements from MedlinePlus and the NHS. They are not trial results.
Form and dose studied
Beta-carotene as it occurs in plant foods.
Who was studied
Everyone eating these foods.
Limits
SR Legacy is from 2018 and values differ between samples. Portion sizes are the ones USDA lists.
Why researchers looked
Many people want to know where beta-carotene comes from in food, and how food compares with pills.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Nutrient database
These are nutrient amounts in foods taken from USDA tables.
A proposed mechanism does not show that the effect happens in people.
Beta-carotene from food has not been linked to the lung cancer risk seen with pills.
Lung cancer in smokers and asbestos-exposed workers (a harm, not a benefit)
Evidence againstTwo large trials gave beta-carotene pills to people at high risk of lung cancer, hoping to prevent it. They found the opposite. In the Finnish ATBC trial of 29,133 male smokers, lung cancer was 18% more common with beta-carotene. In the US CARET trial of 18,314 smokers, former smokers and asbestos workers, a beta-carotene plus vitamin A pill raised lung cancer risk by 28% and the trial was stopped early. The risk is for pills, not for food.
9 studiesBeta-carotene capsules at 20 to 30 mg a day (ATBC, CARET with vitamin…
Studies, doses and limits
What the trials found
ATBC (male smokers aged 50 to 69, Finland, 5 to 8 years): lung cancer incidence +18% (95% CI +3% to +36%) with beta-carotene, total deaths +8%, mainly from lung cancer and ischaemic heart disease. CARET (smokers, former smokers, asbestos workers, average 4 years): relative risk of lung cancer 1.28 (1.04 to 1.57), lung cancer death 1.46 (1.07 to 2.00); the pill combined beta-carotene with vitamin A, so the harm cannot be assigned to beta-carotene alone. A 2010 meta-analysis found lung cancer RR 1.16 overall and RR 1.20 in smokers and asbestos workers, with beta-carotene at trial amounts of 20 to 30 mg a day. A 2020 Cochrane review found vitamin A supplements raised lung cancer in smokers or asbestos workers (RR 1.10, high-certainty), without listing beta-carotene separately in its abstract. In AREDS2, lung cancers were 2.0% with beta-carotene and 0.9% without, mostly in former smokers.
Results
Beta-carotene pills did not prevent lung cancer in people at high risk, and probably raised it. NCCIH, the NEI and the USPSTF all warn against them in smokers, former smokers and asbestos-exposed workers.
Effect sizes as reported
ATBC lung cancer +18% (+3% to +36%); CARET RR 1.28 (1.04 to 1.57); meta-analysis RR 1.16 (1.06 to 1.27), smokers/asbestos RR 1.20 (1.07 to 1.34); AREDS2 23 vs 11 lung cancers.
Why this rating
Against any benefit, and evidence of harm, from two large randomised trials, a meta-analysis and a Cochrane review. Women and former smokers had larger risks in CARET follow-up (planned subgroups).
Form and dose studied
Beta-carotene capsules at 20 to 30 mg a day (ATBC, CARET with vitamin A, pooled trials); amounts are trial figures, not advice.
Who was studied
Male smokers (ATBC), smokers, former smokers and asbestos workers (CARET), former smokers (AREDS2).
Limits
Smoking and asbestos exposure already carry a high lung cancer risk, so the extra risk is of a large baseline. CARET used a combination product. Follow-up showed the extra risk mostly faded after stopping (see Safety).
Why researchers looked
Observational studies had linked high blood beta-carotene and fruit-and-vegetable diets with less lung cancer, so these trials tested whether pills would do the same.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
How beta-carotene pills might raise lung cancer risk was not shown in the abstracts read.
A proposed mechanism does not show that the effect happens in people.
This is the main safety finding on this page. See the Safety tab.
Cancer prevention in people who are not at high risk
Evidence againstIn healthy people who are not heavy smokers, beta-carotene pills did not lower cancer risk. The US Physicians' Health Study (22,071 male doctors, about 12 years) and the Women's Health Study (39,876 women, over 4 years of follow-up) both found no benefit and no harm for cancer overall. A pooled analysis of 9 trials found no effect on all cancers combined.
5 studiesBeta-carotene pills, trial amounts 50 mg on alternate days (PHS, WHS)…
Studies, doses and limits
What the trials found
Physicians' Health Study (male doctors aged 40 to 84, 11% current and 39% former smokers): any cancer relative risk 0.98 (0.91 to 1.06); lung cancer cases 82 with beta-carotene versus 88 with placebo; no difference among smokers. Women's Health Study (women aged 45 or older, 13% smokers): cancer RR 1.03 (0.89 to 1.18), smokers RR 1.11 (0.78 to 1.58); treatment was stopped early after a median of 2.1 years. The 2010 meta-analysis of 9 trials: all cancers RR 1.01 (0.98 to 1.04), with no effect for colorectal, prostate, breast, pancreatic or skin cancers, but more stomach cancer (RR 1.34) at 20 to 30 mg a day. In 2022 the USPSTF concluded with moderate certainty that the harms of beta-carotene supplements outweigh the benefits for preventing cancer or heart disease.
Results
No cancer benefit from pills in people at average risk. Some risk of lung and stomach cancer at higher amounts. Official advice is against using beta-carotene supplements for prevention.
Effect sizes as reported
PHS any cancer RR 0.98 (0.91 to 1.06); WHS RR 1.03 (0.89 to 1.18); meta-analysis all cancers RR 1.01 (0.98 to 1.04).
Why this rating
Evidence against a benefit from several large randomised trials and a meta-analysis; the USPSTF graded the recommendation against as D.
Form and dose studied
Beta-carotene pills, trial amounts 50 mg on alternate days (PHS, WHS) and 20 to 30 mg a day (pooled); not advice.
Who was studied
Healthy male doctors, healthy women aged 45 or older, and pooled trials.
Limits
The Women's Health Study had only a short treatment period. Few participants were current smokers (11% and 13%), so a harm limited to heavy smokers could be missed.
Why researchers looked
Diets rich in colourful fruit and vegetables are linked with less cancer, so pills were tested to see whether the pigment itself was the reason.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
The trials did not test a mechanism.
A proposed mechanism does not show that the effect happens in people.
Safe in these trials for non-smokers over several years does not mean it is shown to be safe for everyone; see Safety.
Deaths and heart disease
Evidence againstPooling 78 antioxidant trials with almost 300,000 people, a Cochrane review found that beta-carotene (and vitamin E) were linked with slightly more deaths in the better-quality trials. The ATBC trial found 8% more deaths with beta-carotene in smokers; the US doctors' trial and the women's trial found no difference. Beta-carotene has not been shown to protect the heart.
7 studiesBeta-carotene and other antioxidants, alone or in combination.
Studies, doses and limits
What the trials found
Cochrane 2012 (78 trials, 296,707 people): all antioxidants RR 1.02 (0.98 to 1.05) in one model and 1.03 in another; in 56 low-risk-of-bias trials RR 1.04 (1.01 to 1.07); for beta-carotene in low-bias trials, 26 trials, RR 1.05 (1.01 to 1.09). The authors say beta-carotene and vitamin E seem to increase deaths. ATBC: total mortality +8% (+1% to +16%). CARET: cardiovascular death RR 1.26 (0.99 to 1.61), not statistically significant. Physicians' Health Study: cardiovascular deaths 338 vs 313, no significant difference. Women's Health Study: deaths 59 vs 55, no difference. CARET follow-up: the extra cardiovascular risk fell to 1.0 after the supplement was stopped. NCCIH says high doses of beta-carotene may increase death from cardiovascular disease.
Results
No heart protection from beta-carotene pills. A small extra risk of death in pooled trials and in smokers.
Effect sizes as reported
Cochrane beta-carotene (low-bias trials) RR 1.05 (1.01 to 1.09); ATBC total deaths +8%; CARET deaths RR 1.17 (1.03 to 1.33).
Why this rating
Against any benefit. The size of the extra risk is small in the pooled data and is clearest in smokers.
Form and dose studied
Beta-carotene and other antioxidants, alone or in combination.
Who was studied
Healthy people and people with stable disease, adults aged 18 to 103 (mean 63).
Limits
The pooled effect is small and differs depending on the statistical model; many trials combined several supplements.
Why researchers looked
Antioxidants were expected to protect blood vessels and the heart, so many trials checked deaths and heart disease.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
Not established; the abstracts do not give a mechanism.
A proposed mechanism does not show that the effect happens in people.
See the Safety tab.
Age-related macular degeneration (as part of the AREDS formula)
Moderate certaintyThe original AREDS eye formula (vitamins C and E, beta-carotene, zinc and copper) lowered the odds of advanced macular degeneration in people who already had signs of it. A 2023 Cochrane review rates this moderate-certainty. Beta-carotene was only one part, and AREDS2 found that removing it did not change how well the formula worked. Smokers and former smokers are advised to avoid the version with beta-carotene.
5 studiesThe AREDS tablet contained beta-carotene (NEI lists 15 mg) with vitam…
Studies, doses and limits
What the trials found
AREDS (3,640 people aged 55 to 80 with signs of AMD, average 6.3 years): antioxidants plus zinc lowered advanced AMD, OR 0.72 (99% CI 0.52 to 0.98); antioxidants alone OR 0.80 (0.59 to 1.09), not statistically significant. AREDS2 (4,203 people, median 5 years): removing beta-carotene had no apparent effect on progression, and more lung cancers occurred with beta-carotene (23 vs 11), mostly in former smokers. The NEI says current smokers were not assigned to beta-carotene in AREDS2, and that current and former smokers should take the AREDS2 formula and avoid the AREDS formula with beta-carotene, which increases lung cancer risk. The 2023 Cochrane review (26 trials, 11,952 people): antioxidant vitamins probably slow progression to late AMD, OR 0.72 (0.58 to 0.90), moderate-certainty, and lutein/zeaxanthin may be a suitable replacement for beta-carotene.
Results
A real, moderate-certainty benefit for the whole formula in people who already have AMD, not for beta-carotene by itself, and not as a way to prevent AMD. People with AMD should ask an eye doctor which formula, if any, suits them.
Effect sizes as reported
AREDS: advanced AMD OR 0.72 (0.52 to 0.98); Cochrane: progression to late AMD OR 0.72 (0.58 to 0.90).
Why this rating
Moderate (Cochrane GRADE) for the antioxidant-and-mineral formula. Beta-carotene's own share cannot be separated, and AREDS2 suggests it is not needed.
Form and dose studied
The AREDS tablet contained beta-carotene (NEI lists 15 mg) with vitamins C and E, zinc and copper; AREDS2 formulas replaced beta-carotene with lutein and zeaxanthin. Amounts are trial figures, not advice.
Who was studied
People with early, intermediate or one-eye advanced AMD.
Limits
Mostly one large trial. The benefit applies to people with AMD only, not to people without it.
Why researchers looked
Macular degeneration is a common cause of vision loss in older people, and oxidative damage was thought to play a part.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
Not established. The AREDS authors tested antioxidants because of earlier findings; the abstract gives no mechanism.
A proposed mechanism does not show that the effect happens in people.
Lung cancer risk from beta-carotene in smokers and former smokers. See Safety.
Cataract
Evidence againstA Cochrane review of 9 trials with 117,272 people found no evidence that antioxidant vitamins, including beta-carotene, lower the risk of cataract or the need for cataract surgery.
2 studiesAntioxidant vitamin supplements above recommended allowances.
Studies, doses and limits
What the trials found
The 2012 Cochrane review: beta-carotene and cataract risk RR 0.99 (95% CI 0.91 to 1.08; 2 trials, 57,703 people); cataract extraction RR 1.00 (0.91 to 1.10; 3 trials, 86,836 people). The authors found no evidence of an effect on progression or loss of vision. NCCIH also says supplements have not been shown to prevent cataract. Yellowing of the skin (hypercarotenodermia) occurred in 7.4% to 15.8% of people taking beta-carotene.
Results
Beta-carotene pills do not prevent cataract in the trials read.
Effect sizes as reported
Beta-carotene and cataract RR 0.99 (0.91 to 1.08).
Why this rating
Evidence against a benefit from pooled randomised trials (reviewers' conclusion: no evidence of effect).
Form and dose studied
Antioxidant vitamin supplements above recommended allowances.
Who was studied
Adults aged 35 or older.
Limits
Cochrane review is from 2012; newer trials were not looked for here.
Why researchers looked
Oxidative damage to the lens was thought to play a part in cataract.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
No mechanism was tested in the abstract.
A proposed mechanism does not show that the effect happens in people.
Skin yellowing was common with beta-carotene.
Thinking and memory
Low certaintyIn one trial of male doctors, men who had taken beta-carotene for about 18 years scored very slightly higher on thinking and memory tests than those on placebo. Men who had taken it for about a year showed no difference. NCCIH describes this evidence as low certainty.
2 studiesBeta-carotene pill, trial amount 50 mg on alternate days (not advice).
Studies, doses and limits
What the trials found
Physicians' Health Study II (5,956 male doctors older than 65): new recruits (about 1 year) showed similar scores. Among 4,052 continuing participants (about 18 years), the global score was higher with beta-carotene by 0.047 standard units (P = .03) and verbal memory by 0.063 (P = .007). The authors say long-term supplementation may provide cognitive benefits. NCCIH reports low-certainty evidence from a 2018 review of 8 studies (about 47,000 people) of better overall cognition after beta-carotene for 18 years, and no effect after shorter periods.
Results
A very small difference seen only after about 18 years of pills, in male doctors. It is a hint, not proof, and must be weighed against the harms in smokers.
Effect sizes as reported
Global thinking score +0.047 standard units; verbal memory +0.063.
Why this rating
Low: one trial group, tiny difference, testing at one time point; NCCIH calls the evidence low certainty.
Form and dose studied
Beta-carotene pill, trial amount 50 mg on alternate days (not advice).
Who was studied
Male physicians older than 65.
Limits
Only men; a tiny difference; not all the original trial members were tested.
Why researchers looked
Oxidative stress contributes to brain ageing, so antioxidants were tested for long-term effects on memory.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
Not tested.
A proposed mechanism does not show that the effect happens in people.
Not assessed in this trial's abstract; see Safety tab for the wider harms.
Colourful fruit and vegetables versus beta-carotene pills
Low certaintyPeople who eat plenty of fruit and vegetables have lower rates of some diseases, but that has not been reproduced by giving the pigment as a pill. MedlinePlus says eating food sources of beta-carotene may reduce cancer risk, while supplements do not. NCCIH says pills may act differently from the amounts in food.
4 studiesFood versus supplement pills.
Studies, doses and limits
What the trials found
MedlinePlus says eating food sources of beta-carotene may reduce cancer risk and that beta-carotene supplements do not. NCCIH says high doses of antioxidants in supplements may have different effects from the smaller amounts in foods; supplements do not reproduce the benefits seen with fruit-and-vegetable diets. The Physicians' Health Study and ATBC abstracts also state that earlier observational studies had suggested lower risk with higher intake.
Results
Do not read food findings as support for pills. No trial compared the two directly.
Effect sizes as reported
No numbers apply (observational statements).
Why this rating
Low for the food link (observational, mixed with lifestyle factors); the pill result is covered by the trials in the other cards.
Form and dose studied
Food versus supplement pills.
Who was studied
General population.
Limits
Observational findings cannot prove food or pigment is the cause.
Why researchers looked
The early interest in beta-carotene came from studies of people who ate more colourful plants.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism Not established
Not established; other substances in plants or other lifestyle factors may explain the food findings (NCCIH).
A proposed mechanism does not show that the effect happens in people.
See Safety.
Antioxidant activity in the lab
Not enough evidenceBeta-carotene is grouped with antioxidants, compounds that can neutralise reactive molecules in laboratory settings. That does not show a pill protects health. In fact large trials of beta-carotene supplements found harm in some groups.
1 studiesNot applicable.
Studies, doses and limits
What the trials found
NCCIH describes beta-carotene as an antioxidant available as a supplement and says extensive studies of antioxidant supplements were done, with much of the research on vitamin E and beta-carotene. No lab or animal paper was read for this page.
Results
Lab activity does not predict benefit in people.
Effect sizes as reported
No effect sizes apply.
Why this rating
Insufficient: lab activity was not tested in the sources read, and human trials did not show a benefit.
Limits
No lab or animal studies were read.
Why researchers looked
Antioxidant activity in the lab is why beta-carotene was tested in prevention trials.
Traditional use
Beta-carotene is a plant pigment the body can turn into vitamin A. Its role as a nutrient from food is well established; that is different from showing that beta-carotene pills prevent or treat a condition.
Proposed mechanism In vitro and reference
Lab antioxidant activity. NCCIH says purified antioxidants in supplements may act differently from those in foods.
A proposed mechanism does not show that the effect happens in people.
See Safety.
Connections to the rest of health
How Beta-carotene connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Preventive Wellness | High certainty | Source of vitamin A (provitamin A): Beta-carotene is an orange-yellow plant pigment that the body converts into vitamin A. Vitamin A helps vision in dim light and keeps the skin, the lining of the nose and mouth, and the immune system healthy. Both MedlinePlus and the NHS say you can get vitamin A from beta-carotene in food. Neither says beta-carotene pills are needed. | 17 20 | |
| Immune Support | High certainty | Source of vitamin A (provitamin A): Beta-carotene is an orange-yellow plant pigment that the body converts into vitamin A. Vitamin A helps vision in dim light and keeps the skin, the lining of the nose and mouth, and the immune system healthy. Both MedlinePlus and the NHS say you can get vitamin A from beta-carotene in food. Neither says beta-carotene pills are needed. | 17 20 | |
| Preventive Wellness | High certainty | Food sources of beta-carotene: Beta-carotene gives orange, yellow and dark green foods their colour. By USDA data, one cup of baked sweet potato has about 23 mg, a cup of cooked spinach about 11 mg, half a cup of cooked carrots about 6.5 mg, a cup of cantaloupe cubes about 3.2 mg, a cup of cooked kale about 2.0 mg and a cup of mango pieces about 1.1 mg. The body takes it up better when the food is eaten with a little fat. | 22 17 20 | |
| Cellular Protection | Evidence against | Lung cancer in smokers and asbestos-exposed workers (a harm, not a benefit): Two large trials gave beta-carotene pills to people at high risk of lung cancer, hoping to prevent it. They found the opposite. In the Finnish ATBC trial of 29,133 male smokers, lung cancer was 18% more common with beta-carotene. In the US CARET trial of 18,314 smokers, former smokers and asbestos workers, a beta-carotene plus vitamin A pill raised lung cancer risk by 28% and the trial was stopped early. The risk is for pills, not for food. | 3 13 8 15 16 6 5 1 18 | |
| Preventive Wellness | Evidence against | Cancer prevention in people who are not at high risk: In healthy people who are not heavy smokers, beta-carotene pills did not lower cancer risk. The US Physicians' Health Study (22,071 male doctors, about 12 years) and the Women's Health Study (39,876 women, over 4 years of follow-up) both found no benefit and no harm for cancer overall. A pooled analysis of 9 trials found no effect on all cancers combined. | 10 11 6 14 18 | |
| Cellular Protection | Evidence against | Cancer prevention in people who are not at high risk: In healthy people who are not heavy smokers, beta-carotene pills did not lower cancer risk. The US Physicians' Health Study (22,071 male doctors, about 12 years) and the Women's Health Study (39,876 women, over 4 years of follow-up) both found no benefit and no harm for cancer overall. A pooled analysis of 9 trials found no effect on all cancers combined. | 10 11 6 14 18 | |
| Heart Health | Evidence against | Deaths and heart disease: Pooling 78 antioxidant trials with almost 300,000 people, a Cochrane review found that beta-carotene (and vitamin E) were linked with slightly more deaths in the better-quality trials. The ATBC trial found 8% more deaths with beta-carotene in smokers; the US doctors' trial and the women's trial found no difference. Beta-carotene has not been shown to protect the heart. | 4 3 13 10 11 8 18 | |
| Healthy Aging | Moderate certainty | Age-related macular degeneration (as part of the AREDS formula): The original AREDS eye formula (vitamins C and E, beta-carotene, zinc and copper) lowered the odds of advanced macular degeneration in people who already had signs of it. A 2023 Cochrane review rates this moderate-certainty. Beta-carotene was only one part, and AREDS2 found that removing it did not change how well the formula worked. Smokers and former smokers are advised to avoid the version with beta-carotene. | 2 1 7 19 18 | |
| Healthy Aging | Evidence against | Cataract: A Cochrane review of 9 trials with 117,272 people found no evidence that antioxidant vitamins, including beta-carotene, lower the risk of cataract or the need for cataract surgery. | 12 18 | |
| Memory Support | Low certainty | Thinking and memory: In one trial of male doctors, men who had taken beta-carotene for about 18 years scored very slightly higher on thinking and memory tests than those on placebo. Men who had taken it for about a year showed no difference. NCCIH describes this evidence as low certainty. | 9 18 | |
| Brain Health | Low certainty | Thinking and memory: In one trial of male doctors, men who had taken beta-carotene for about 18 years scored very slightly higher on thinking and memory tests than those on placebo. Men who had taken it for about a year showed no difference. NCCIH describes this evidence as low certainty. | 9 18 | |
| Healthy Aging | Low certainty | Thinking and memory: In one trial of male doctors, men who had taken beta-carotene for about 18 years scored very slightly higher on thinking and memory tests than those on placebo. Men who had taken it for about a year showed no difference. NCCIH describes this evidence as low certainty. | 9 18 | |
| Preventive Wellness | Low certainty | Colourful fruit and vegetables versus beta-carotene pills: People who eat plenty of fruit and vegetables have lower rates of some diseases, but that has not been reproduced by giving the pigment as a pill. MedlinePlus says eating food sources of beta-carotene may reduce cancer risk, while supplements do not. NCCIH says pills may act differently from the amounts in food. | 17 18 10 3 | |
| Cellular Protection | Not enough evidence | Antioxidant activity in the lab: Beta-carotene is grouped with antioxidants, compounds that can neutralise reactive molecules in laboratory settings. That does not show a pill protects health. In fact large trials of beta-carotene supplements found harm in some groups. | 18 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Nutrition | Biological association | High certainty | Studied for: Source of vitamin A (provitamin A) Studied for: Food sources of beta-carotene | 17 20 22 |
| Eyes And Vision | Biological association | High certainty | Studied for: Source of vitamin A (provitamin A) Studied for: Age-related macular degeneration (as part of the AREDS formula) | 17 20 2 1 7 19 18 12 |
| Immune System | Biological association | High certainty | Studied for: Source of vitamin A (provitamin A) | 17 20 |
| Digestive System | Biological association | High certainty | Studied for: Food sources of beta-carotene | 22 17 20 |
| Respiratory System | Biological association | Evidence against | Studied for: Lung cancer in smokers and asbestos-exposed workers (a harm, not a benefit) | 3 13 8 15 16 6 5 1 18 |
| Whole Body | Biological association | Evidence against | Studied for: Cancer prevention in people who are not at high risk Studied for: Colourful fruit and vegetables versus beta-carotene pills | 10 11 6 14 18 17 3 |
| Cardiovascular System | Biological association | Evidence against | Studied for: Deaths and heart disease | 4 3 13 10 11 8 18 |
| Heart Circulation | Biological association | Evidence against | Studied for: Deaths and heart disease | 4 3 13 10 11 8 18 |
| Nervous System | Biological association | Low certainty | Studied for: Thinking and memory | 9 18 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Lung cancer | Adverse effect or risk | Documented risk | More lung cancer with beta-carotene pills in smokers, former smokers and asbestos-exposed workers. Preparation or compound: Beta-carotene supplements |
3 13 1 6 |
| Age-related macular degeneration | Preliminary | The whole AREDS formula slowed progression in people who already had AMD; beta-carotene's own share is not separable. Preparation or compound: AREDS formula (original, with beta-carotene) |
2 7 1 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Lung cancer cases | Biological association | Evidence against | Measured in trials: higher with beta-carotene in smokers and asbestos workers. A lab change is not the same as a health benefit. | 3 13 10 |
| Deaths from any cause | Biological association | Low certainty | Measured in trials: slightly higher in smokers and in pooled trials. A lab change is not the same as a health benefit. | 4 3 10 |
| Any cancer (all types) | Biological association | Evidence against | Measured in trials: no change. A lab change is not the same as a health benefit. | 6 11 |
| Progression to advanced AMD | Biological association | Moderate certainty | Measured in trials: lower with the whole formula (moderate certainty). A lab change is not the same as a health benefit. | 2 7 |
| Yellowing of the skin (hypercarotenodermia) | Biological association | Moderate certainty | Measured in trials: more with beta-carotene. A lab change is not the same as a health benefit. | 12 17 |
K. Biological pathways
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Beta-carotene | Biological association | Human | Provitamin A: converted to vitamin A in the body; antioxidant in the laboratory. Preparation or compound: Orange, yellow and dark green fruit and vegetables (carrots, sweet potatoes, spinach, mango, cantaloupe) |
17 20 18 |
| Retinyl palmitate (with beta-carotene in CARET) | Biological association | Human | A vitamin A form given together with beta-carotene in CARET. | 13 17 |
| Lutein and zeaxanthin | Biological association | Human | Carotenoids found in the eye; used in the AREDS2 formula in place of beta-carotene. | 19 1 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).
Evidence at a glance: what the research found for 10 outcomes
Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.
The evidence
The research centre for Beta-carotene. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing beta-carotene summary, read pages from NCCIH, the National Eye Institute, MedlinePlus and the NHS, re-checked food values in saved USDA FoodData Central data, and re-read PubMed abstracts for the trials and reviews. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.
Study library: every study we checked 22
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Age-Related Eye Disease Study 2 Research Group 2013 Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA · PMID 23644932 · DOI |
Controlled trial |
4203 People aged 50 to 85 at risk of advanced AMD |
AREDS formula with or without beta-carotene, with or without lutein and zeaxanthin Trial formulas (not advice) Median 5 years · vs Placebo / AREDS formula |
Removing beta-carotene had no apparent effect on AMD progression. More lung cancers occurred in the beta-carotene group, mostly in former smokers. The authors say lutein plus zeaxanthin could be an appropriate substitute. Lung cancer 23 (2.0%) with beta-carotene vs 11 (0.9%) without; nominal P = .04 (Not given in the abstract for lung cancer) Methods, limits and fundingOutcomes: Progression to advanced AMD; lung cancer (safety) Limitations: Lung cancer was a safety observation, not the main outcome. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Registration: NCT00345176 Read: abstract |
| Age-Related Eye Disease Study Research Group 2001 A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol · PMID 11594942 · DOI |
Controlled trial |
3640 People aged 55 to 80 with signs of age-related macular degeneration (AMD) |
Antioxidant formula (vitamin C, vitamin E, beta-carotene) with and without zinc and copper Trial formula; the antioxidant tablet contained beta-carotene (NEI lists 15 mg); not advice Average 6.3 years · vs Placebo |
Antioxidants plus zinc lowered the odds of advanced AMD. Antioxidants alone did not reach statistical significance. No significant serious side effects were found. The abstract's conclusion excludes people with contraindications such as smoking. Antioxidants plus zinc OR 0.72; antioxidants alone OR 0.80 (not significant) (Antioxidants plus zinc 99% CI 0.52 to 0.98; antioxidants alone 0.59 to 1.09) Methods, limits and fundingOutcomes: Progression to advanced AMD; loss of visual acuity Limitations: Beta-carotene was one part of a multi-nutrient formula, so its own effect cannot be separated. Abstract read only. Funding and conflicts: Funding not stated in the abstract. NCCIH says AREDS and AREDS2 were sponsored by the US National Institutes of Health. Read: abstract |
| Alpha-Tocopherol 1994 The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med · PMID 8127329 · DOI |
Controlled trial |
29133 Male smokers aged 50 to 69 in southwestern Finland (the ATBC trial) |
Beta-carotene supplement pill, alone or with alpha-tocopherol (vitamin E) Trial amount: 20 mg a day (not advice) 5 to 8 years · vs Placebo (2 x 2 design with vitamin E) |
Beta-carotene group had more lung cancer than those not given it, and 8 percent higher total deaths, mainly from lung cancer and ischaemic heart disease. Vitamin E did not reduce lung cancer. Lung cancer incidence +18% with beta-carotene; total mortality +8% (Lung cancer 95% CI +3% to +36%; mortality 95% CI +1% to +16%) Methods, limits and fundingOutcomes: Lung cancer and other cancers; total deaths Limitations: Male smokers only; the lung cancer rise was unexpected, so it was not the planned hypothesis. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Bjelakovic 2012 Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev · PMID 22419320 · DOI |
Systematic review meta analysis |
296707 78 trials in healthy people and people with stable diseases (beta-carotene, vitamins A, C, E, selenium) |
Antioxidant supplements, including beta-carotene Varied (pooled) 28 days to 12 years (mean 3 years) · vs Placebo or no intervention |
Overall, antioxidant supplements did not change deaths in one model and slightly raised them in another. In low-risk-of-bias trials, beta-carotene and vitamin E were linked with more deaths. All antioxidants RR 1.02 (random effects); low-bias trials RR 1.04; beta-carotene (26 low-bias trials) RR 1.05 (All 0.98 to 1.05; low-bias 1.01 to 1.07; beta-carotene 1.01 to 1.09) Methods, limits and fundingOutcomes: Deaths from any cause Limitations: Pools many different supplements; the effect for beta-carotene is small. Abstract read only. Funding and conflicts: Authors report no known conflicts of interest. Read: abstract |
| Cortes-Jofre 2020 Drugs for preventing lung cancer in healthy people. Cochrane Database Syst Rev · PMID 32130738 · DOI |
Systematic review meta analysis |
12 randomised trials of vitamins and minerals in healthy people | Vitamin A group (the abstract does not say which forms; the trials include smoker and asbestos trials) Pooled Varied · vs Placebo |
No beneficial effect of supplements for preventing lung cancer. In smokers or asbestos workers, the vitamin A group had more lung cancer, lung cancer deaths and all-cause deaths (high-certainty evidence). Skin yellowing and minor stomach symptoms were more common. In smokers/asbestos workers: lung cancer RR 1.10; lung cancer death RR 1.18; any death RR 1.09 (Lung cancer 1.01 to 1.20; lung cancer death 1.01 to 1.38; any death 1.05 to 1.13) Methods, limits and fundingOutcomes: Lung cancer incidence and deaths Limitations: The abstract groups the trials as 'vitamin A' and does not list beta-carotene separately, so this is read as supporting, not as a beta-carotene-only result. Abstract read only. Funding and conflicts: Authors report no known conflicts of interest. Read: abstract |
| Druesne-Pecollo 2010 Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials. Int J Cancer · PMID 19876916 · DOI |
Systematic review meta analysis |
9 randomised trials (13 publications) searched to April 2009 | Beta-carotene supplements Pooled; harm seen at trial amounts of 20 to 30 mg a day (not advice) Varied · vs Placebo |
No effect on all cancers combined. Lung and stomach cancers were more frequent with beta-carotene at 20 to 30 mg a day, and more so in smokers and asbestos workers. The authors say beta-carotene should not be recommended for cancer prevention. All cancers RR 1.01; lung RR 1.16; stomach RR 1.34; in smokers and asbestos workers lung RR 1.20 and stomach RR 1.54 (All cancers 0.98 to 1.04; lung 1.06 to 1.27; stomach 1.06 to 1.70; smokers/asbestos lung 1.07 to 1.34, stomach 1.08 to 2.19) Methods, limits and fundingOutcomes: Cancer incidence by site Limitations: Pooled trials differ; the grading of certainty is not in the abstract. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Evans 2023 Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration. Cochrane Database Syst Rev · PMID 37702300 · DOI |
Systematic review meta analysis |
11952 26 trials in people with AMD, aged 65 to 75 |
Antioxidant vitamins and minerals (AREDS: vitamin C, vitamin E, beta-carotene, zinc) Pooled Varied · vs Placebo or no intervention |
Moderate-certainty evidence that the antioxidant and mineral formula probably slows progression to late AMD. The review notes lutein/zeaxanthin may be a suitable replacement for beta-carotene. Progression to late AMD OR 0.72 (3 studies, 2,445 people); neovascular AMD OR 0.62 (AREDS) (Late AMD 0.58 to 0.90; neovascular 0.47 to 0.82) Methods, limits and fundingOutcomes: Progression to late AMD; vision loss Limitations: Mostly one large trial (AREDS). Beta-carotene is not tested alone. Abstract read only. Funding and conflicts: Authors report no known conflicts of interest. Read: abstract |
| Goodman 2004 The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements. J Natl Cancer Inst · PMID 15572756 · DOI |
Rct follow up |
18314 CARET participants followed after the supplements were stopped |
Beta-carotene combined with retinyl palmitate (earlier trial) Follow-up through 2001 (about 6 years after stopping) · vs Placebo group |
After stopping, lung cancer and all-cause death risks stayed above 1.0 but were no longer statistically significant. The extra heart-disease risk fell to 1.0. Women had larger risks than men in planned subgroup analyses. Post-trial lung cancer RR 1.12; all-cause death RR 1.08 (Lung cancer 0.97 to 1.31; all-cause death 0.99 to 1.17) Methods, limits and fundingOutcomes: Lung cancer, deaths, heart-disease deaths after stopping Limitations: Subgroup differences (women, former smokers) were exploratory. Combination product. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Grodstein 2007 A randomized trial of beta carotene supplementation and cognitive function in men: the Physicians' Health Study II. Arch Intern Med · PMID 17998490 · DOI |
Controlled trial |
5956 Male physicians older than 65 given thinking tests (1,904 new recruits and 4,052 continuing from the original trial) |
Beta-carotene supplement pill Trial amount: 50 mg on alternate days (not advice) About 1 year (new recruits) or about 18 years (continuing) · vs Placebo |
No difference after about a year. After about 18 years, scores were slightly higher with beta-carotene. The authors say long-term supplements may give cognitive benefits. Global score difference 0.047 z-score units (P = .03); verbal memory 0.063 (P = .007) (Not given in the abstract) Methods, limits and fundingOutcomes: Global thinking score; verbal memory Limitations: Very small difference; male doctors only; testing was done once near the end of the trial. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Hennekens 1996 Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med · PMID 8602179 · DOI |
Controlled trial |
22071 US male physicians aged 40 to 84; 11% current and 39% former smokers (Physicians' Health Study) |
Beta-carotene supplement pill Trial amount: 50 mg on alternate days (not advice) About 12 years · vs Placebo |
No difference in cancer, heart disease or deaths. Among current and former smokers there were also no significant differences. Any cancer RR 0.98; lung cancer 82 vs 88 cases; deaths 979 vs 968 (Any cancer 0.91 to 1.06) Methods, limits and fundingOutcomes: Cancer, cardiovascular disease and all-cause deaths Limitations: Mostly non-smoking male doctors; compliance was 78 percent. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Lee 1999 Beta-carotene supplementation and incidence of cancer and cardiovascular disease: the Women's Health Study. J Natl Cancer Inst · PMID 10601381 · DOI |
Controlled trial |
39876 Women aged 45 or older, apparently healthy; 13% smokers (beta-carotene part of the Women's Health Study) |
Beta-carotene supplement pill Trial amount: 50 mg on alternate days (not advice) Median 2.1 years of treatment, 4.1 years of follow-up · vs Placebo |
No benefit or harm in cancer, cardiovascular disease or deaths for a limited time. Among smokers (13%) there were no significant differences. Cancer RR 1.03; smokers' cancer RR 1.11 (Cancer 0.89 to 1.18; smokers 0.78 to 1.58) Methods, limits and fundingOutcomes: Cancer, cardiovascular disease, deaths Limitations: The beta-carotene part ended early, so exposure was short. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Mathew 2012 Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract. Cochrane Database Syst Rev · PMID 22696344 · DOI |
Systematic review meta analysis |
117272 9 trials in people aged 35 or older |
Antioxidant vitamins including beta-carotene Pooled; above recommended allowances 2.1 to 12 years · vs Placebo or other vitamin |
No evidence that antioxidant vitamins, including beta-carotene, lower the risk of cataract or cataract surgery. Yellowing of the skin occurred in 7.4% to 15.8% of people taking beta-carotene. Beta-carotene and cataract RR 0.99; cataract surgery RR 1.00 (Cataract 0.91 to 1.08; surgery 0.91 to 1.10) Methods, limits and fundingOutcomes: Cataract, cataract surgery, vision Limitations: Abstract read only. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Omenn 1996 Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med · PMID 8602180 · DOI |
Controlled trial |
18314 Smokers, former smokers and asbestos-exposed workers in the USA (the CARET trial) |
Beta-carotene combined with retinyl palmitate (a vitamin A form) Trial amount: beta-carotene 30 mg and retinol 25,000 IU a day (not advice) Average 4.0 years; stopped 21 months early · vs Placebo |
The combination group had more lung cancer and more deaths. The trial was stopped early. Because beta-carotene and vitamin A were given together, the harm cannot be assigned to beta-carotene alone. Lung cancer RR 1.28; death from any cause RR 1.17; lung cancer death RR 1.46; cardiovascular death RR 1.26 (not statistically significant) (Lung cancer 1.04 to 1.57; any death 1.03 to 1.33; lung cancer death 1.07 to 2.00; cardiovascular death 0.99 to 1.61) Methods, limits and fundingOutcomes: Lung cancer incidence; deaths Limitations: Combination product, not beta-carotene alone. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| US Preventive Services Task Force; Mangione 2022 Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement. JAMA · PMID 35727271 · DOI |
Guideline |
Non-pregnant adults in the general population | Beta-carotene supplements (and vitamin E, multivitamins, other single nutrients) |
The Task Force concluded with moderate certainty that the harms of beta-carotene supplements outweigh the benefits for preventing cardiovascular disease or cancer, and recommends against them (grade D). Recommendation: against (D) (Not applicable) Methods, limits and fundingOutcomes: Prevention of cardiovascular disease and cancer Limitations: A recommendation for general adults; it is not personal advice. Abstract read only. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Virtamo 2003 Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up. JAMA · PMID 12876090 · DOI |
Rct follow up |
25563 Finnish male smokers followed after the ATBC trial |
Beta-carotene supplement (earlier trial) 6 years for cancer, 8 years for deaths after the trial ended · vs Placebo group |
After the trial ended, lung cancer risk was no longer clearly higher, and the extra risk of death was no longer evident 4 to 6 years after stopping. The excess was mainly from cardiovascular disease. The authors conclude that smokers should avoid beta-carotene supplements. Post-trial lung cancer RR 1.06; deaths RR 1.07 (Lung cancer 0.94 to 1.20; deaths 1.02 to 1.12) Methods, limits and fundingOutcomes: Lung cancer and deaths after stopping Limitations: Male smokers only. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Virtamo 2014 Effects of alpha-tocopherol and beta-carotene supplementation on cancer incidence and mortality: 18-year postintervention follow-up of the Alpha-tocopherol, Beta-carotene Cancer Prevention Study. Int J Cancer · PMID 24338499 · DOI |
Rct follow up |
25563 Finnish male smokers followed for 18 years after the ATBC trial |
Beta-carotene supplement (earlier trial) 18 years after the trial · vs Placebo group |
No late effect of beta-carotene on cancer incidence or total deaths. Prostate cancer deaths were higher in the beta-carotene group. Post-trial lung cancer RR 1.04; deaths RR 1.02; prostate cancer death RR 1.20 (Lung cancer 0.96 to 1.11; deaths 0.99 to 1.05; prostate cancer death 1.01 to 1.42) Methods, limits and fundingOutcomes: Cancer incidence and deaths after stopping Limitations: The prostate cancer death result is one of several outcomes checked, so it may be chance. Male smokers only. Abstract read only. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| s-medlineplus-vitamin-a MedlinePlus Medical Encyclopedia: Vitamin A (review date 2025-01-21) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-nccih-antioxidants NCCIH (US National Center for Complementary and Integrative Health): Antioxidants - In Depth (page 'Last Updated: July 2023') · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-nei-areds National Eye Institute: About AREDS and AREDS2 (page last updated 2025-10-22) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-nhs-vitamin-a NHS: Vitamins and minerals - Vitamin A (page last reviewed 2020-08-03) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-ods-vitamin-a NIH Office of Dietary Supplements: Vitamin A and Carotenoids fact sheet for health professionals · Source |
Reference database n/a |
Methods, limits and fundingRead: not-read | ||
| s-usda-sr-legacy-beta-carotene USDA FoodData Central, SR Legacy (April 2018 release): beta-carotene content of common foods · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text |
What we do not know yet
- No trial was read showing that beta-carotene pills help people who already get enough vitamin A.
- How beta-carotene pills raised lung cancer risk was not explained in the sources read.
- CARET gave beta-carotene together with vitamin A, so its harm cannot be assigned to beta-carotene alone.
- The NIH Office of Dietary Supplements fact sheet could not be read (the site blocked access), so any official upper intake level it gives is not stated.
- No source was read on contamination or label accuracy of beta-carotene supplements, or on beta-carotene pills in pregnancy or children.
- Beta-carotene for the skin condition erythropoietic protoporphyria was not researched here.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 5
Lung cancer cases
Higher with beta-carotene in smokers and asbestos workers in trials
How many people in each group were diagnosed with lung cancer during the trial.
Evidence againstResults and what it means
Why it was measured
To see whether beta-carotene prevents lung cancer in smokers.
Statistical vs. clinical meaning
Higher in groups at high risk; no change in healthy people.
Safety implication
This is the central safety finding.
| Study | Result | People | Product |
|---|---|---|---|
| 3 | +18% (95% CI +3% to +36%) | 29,133 male smokers | Beta-carotene pill |
| 13 | RR 1.28 (95% CI 1.04 to 1.57) | 18,314 smokers, former smokers and asbestos workers | Beta-carotene plus vitamin A |
| 10 | 82 cases with beta-carotene versus 88 with placebo, no significant difference | 22,071 male doctors, 11% current smokers | Beta-carotene pill |
Deaths from any cause
Slightly higher in smokers and in pooled trials in trials
How many people died from any cause during the trial.
Low certaintyResults and what it means
Why it was measured
To see whether beta-carotene changes length of life.
Statistical vs. clinical meaning
A small extra risk, mainly seen in smokers.
Safety implication
See the Safety tab.
Any cancer (all types)
No change in trials
How many people were diagnosed with any cancer.
Evidence againstResults and what it means
Why it was measured
To see whether beta-carotene pills lower cancer risk.
Statistical vs. clinical meaning
No protective effect.
Safety implication
Lung and stomach cancer were more common at 20 to 30 mg a day in the pooled analysis.
Progression to advanced AMD
Lower with the whole formula (moderate certainty) in trials
Whether early or intermediate AMD became advanced AMD during follow-up.
Moderate certaintyResults and what it means
Why it was measured
To see whether the antioxidant formula slows macular degeneration.
Statistical vs. clinical meaning
Moderate certainty for the whole formula, not for beta-carotene alone.
Safety implication
Lung cancer risk with beta-carotene in smokers.
| Study | Result | People | Product |
|---|---|---|---|
| 2 | OR 0.72 (99% CI 0.52 to 0.98) antioxidants plus zinc; antioxidants alone OR 0.80 (0.59 to 1.09) | 3,640 people with AMD signs | AREDS antioxidant formula with beta-carotene, with and without zinc and copper |
| 7 | OR 0.72 (95% CI 0.58 to 0.90); 3 studies, 2,445 people | People with early or intermediate AMD | Antioxidant vitamin and mineral supplements |
Yellowing of the skin (hypercarotenodermia)
More with beta-carotene in trials
Skin turning yellow or orange from carotene building up.
Moderate certaintyResults and what it means
Why it was measured
A visible, harmless sign of high beta-carotene intake.
Statistical vs. clinical meaning
Common with high intake; MedlinePlus says colour returns to normal after intake is reduced.
Safety implication
Harmless colour change, not jaundice.
| Study | Result | People | Product |
|---|---|---|---|
| 12 | 7.4% to 15.8% of people taking beta-carotene developed it | Participants in trials of beta-carotene | Beta-carotene supplements |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 4
- Beta-carotene pills raised lung cancer risk in smokers and asbestos-exposed workers. In the ATBC trial of 29,133 male smokers, lung cancer was 18% more common with beta-carotene pills. In the CARET trial of 18,314 smokers, former smokers and asbestos workers, a beta-carotene plus vitamin A pill raised lung cancer risk (relative risk 1.28) and the trial was stopped early. In AREDS2, more lung cancers occurred with beta-carotene, mostly in former smokers. The NEI advises current and former smokers to avoid the eye formula with beta-carotene, and the USPSTF recommends against beta-carotene supplements for preventing cancer or heart disease. Randomised trials, meta analysis and authoritative guidance 3 13 1 6 19 14 18
- Slightly more deaths in smokers and in pooled trials. ATBC found 8% more deaths with beta-carotene, mainly from lung cancer and heart disease. CARET found 17% more deaths from any cause in the beta-carotene plus vitamin A group. A Cochrane review of low-risk-of-bias trials found beta-carotene was linked with a small rise in deaths (relative risk 1.05). NCCIH says high doses of beta-carotene may increase death from cardiovascular disease. Two trials in mostly non-smoking healthy people (male doctors and women) found no difference in deaths. Randomised trials and meta analysis 3 13 4 10 11 18
- The extra risk seems to fade after stopping. After ATBC ended, the extra risk of death was no longer evident 4 to 6 years after stopping, and an 18-year follow-up found no late effect on lung cancer or total deaths. In CARET, risks stayed above 1.0 but were no longer statistically significant, and the extra cardiovascular risk fell to 1.0. The 18-year ATBC follow-up did find more prostate cancer deaths in the beta-carotene group (relative risk 1.20), which may be a chance finding. This is not a reason to start or continue pills; it describes what the follow-ups reported. Randomised trial follow ups 15 16 8
- Food beta-carotene is different from pills. MedlinePlus says eating food sources of beta-carotene may reduce cancer risk, and that supplements do not and may raise risk in smokers and asbestos workers. The harms above were found with pills. NCCIH says supplements may act differently from the amounts found in food. Authoritative guidance 17 18
Side effects 5
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Lung cancer (in smokers, former smokers and asbestos-exposed workers) CARET combined beta-carotene with vitamin A, so the harm cannot be assigned to beta-carotene alone. | ATBC: +18% (95% CI +3% to +36%). CARET: relative risk 1.28 (1.04 to 1.57) with a beta-carotene plus vitamin A pill. Pooled trials: smokers and asbestos workers relative risk 1.20 (1.07 to 1.34). AREDS2: 23 lung cancers (2.0%) with beta-carotene versus 11 (0.9%) without. | Serious After stopping, excess risk was no longer statistically significant in follow-ups, but remained above 1.0 in CARET. | Randomised trials and meta analysis 3 13 6 1 8 |
| Death from any cause, mainly lung cancer and heart disease The physicians' and women's trials, with few current smokers, found no difference in deaths. | ATBC: +8% (1% to 16%). CARET: relative risk 1.17 (1.03 to 1.33). Cochrane, beta-carotene in low-bias trials: relative risk 1.05 (1.01 to 1.09). | Serious In ATBC the excess was no longer evident 4 to 6 years after stopping. | Randomised trials and meta analysis 3 13 4 15 |
| Stomach cancer Stomach cancer was one of several cancer sites checked in the pooled analysis; the abstract does not give case numbers. | Pooled trials: relative risk 1.34 (1.06 to 1.70) at 20 to 30 mg a day; 1.54 (1.08 to 2.19) in smokers and asbestos workers. | Serious Not described. | Meta-analysis 6 |
| Yellow or orange skin (hypercarotenodermia) MedlinePlus says large amounts of beta-carotene will not make you seriously ill. | 7.4% to 15.8% of people taking beta-carotene in the trials in a Cochrane cataract review. | Harmless colour change MedlinePlus: skin colour returns to normal once beta-carotene intake is reduced. | Meta analysis and authoritative guidance 12 17 |
| Minor stomach and bowel symptoms Read as supporting, not as a beta-carotene-only result. | Cochrane lung cancer review: more minor stomach and bowel symptoms and skin yellowing with the vitamin A group (high-certainty). The abstract does not list beta-carotene separately. | Minor Not described. | Meta-analysis 5 |
Liver
No liver injury from beta-carotene was found in the sources read. MedlinePlus says large amounts of beta-carotene will not make you seriously ill, unlike large amounts of preformed vitamin A (retinol), which can cause serious illness. A liver-safety reference (LiverTox) was not opened for this page. 17
How often. No frequency was found.
Monitoring. No agency monitoring advice was found.
This is a safety connection. It is not evidence that Beta-carotene supports liver health.
Medicines and supplements 6
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Smoking and asbestos exposure lifestyle and exposure | How the combination raises lung cancer risk was not explained in the abstracts read. | The harm was found in smokers, former smokers and asbestos-exposed workers in ATBC, CARET and AREDS2. NCCIH and the NEI name these groups as being at highest risk. | Randomised trials High certainty 3 13 1 19 18 | If you smoke, used to smoke or have worked with asbestos, ask a doctor or pharmacist before any product that contains beta-carotene, including multivitamins and eye formulas. |
| Preformed vitamin A (retinol, retinyl palmitate) supplement | CARET gave beta-carotene together with retinyl palmitate; the effects cannot be separated. MedlinePlus says large amounts of preformed vitamin A can cause serious illness and birth defects. | The harm in CARET came from the combination. Many multivitamins contain both forms (NHS). | Randomised trial and authoritative guidance Moderate certainty 13 17 20 | Check labels and ask a pharmacist before combining vitamin A products. |
| Vitamin E (alpha-tocopherol) supplement | Tested together in the ATBC 2 x 2 design. | ATBC found no interaction between alpha-tocopherol and beta-carotene for lung cancer. NCCIH notes vitamin E has its own risks (bleeding), not covered here. | Randomised trial Moderate certainty 3 18 | Do not assume that adding other antioxidants makes beta-carotene safer for smokers. Ask a pharmacist. |
| Cholesterol-lowering drugs taken together prescription | Not given by NCCIH. | NCCIH reports that in one study, a combination of vitamin E, vitamin C, selenium and beta-carotene reduced the cholesterol-lowering effect of two drugs taken together. The drugs are not named in the NCCIH text read. | Authoritative guidance (one study) Low certainty 18 | Tell your prescriber or pharmacist if you take antioxidant supplements with cholesterol medicines. |
| Cancer treatment (chemotherapy and radiation) prescription | NCCIH says antioxidants might interact unfavourably with cancer treatment. It cites a 2019 study of women with breast cancer in which antioxidant supplement use during chemotherapy was linked with higher risk of recurrence and death; the supplements in that study included vitamins A, C and E, carotenoids and coenzyme Q10, not beta-carotene alone. | Not shown for beta-carotene alone. NCCIH advises checking with the people managing your cancer treatment before using antioxidant supplements. | Authoritative guidance (observational) Very low certainty 18 | Ask your cancer care team before using any antioxidant supplement. |
| Other carotenoid supplements and fat-absorption drugs supplement and prescription | Not checked against any source. | No interaction data were read for these. | None read Not enough evidence | Ask a pharmacist. |
Who should check first 5
| Situation | Advice | Evidence |
|---|---|---|
| Current smokers, former smokers and people exposed to asbestos | The USPSTF recommends against beta-carotene supplements for preventing heart disease or cancer in adults. The NEI says current and former smokers should avoid the original AREDS eye formula that contains beta-carotene and use the AREDS2 formula instead. The ATBC authors conclude smokers should avoid beta-carotene supplements. | Authoritative guidance and randomised trials 14 19 15 3 |
| Pregnancy and breastfeeding | No source read gave advice on beta-carotene supplements in pregnancy. MedlinePlus says large doses of preformed vitamin A in pregnancy can cause birth defects; that warning is about retinol, not beta-carotene, but products can contain both. The NHS says to avoid liver and liver products in pregnancy. Ask a doctor or pharmacist before any vitamin A or beta-carotene product. | Authoritative guidance 17 20 |
| Infants and children | MedlinePlus says babies and children are more sensitive to vitamin A and can become ill from smaller amounts. This is stated about vitamin A; no source read gave advice about beta-carotene pills in children. Do not give children beta-carotene or vitamin A supplements without a doctor or pharmacist's advice. | Authoritative guidance 17 |
| People with age-related macular degeneration | NCCIH says people with AMD should ask their health care providers whether AREDS or AREDS2-type supplements are appropriate. Smokers and former smokers are advised to avoid the formula with beta-carotene. | Authoritative guidance 18 19 |
| People having cancer treatment | NCCIH advises checking with the health care providers managing cancer treatment before taking antioxidant supplements. | Authoritative guidance 18 |
Overdose, product quality and regulators
Summary. Beta-carotene from food is not known to be toxic. MedlinePlus says large amounts of beta-carotene will not make you seriously ill but can turn the skin yellow or orange. The serious concern is not poisoning but long-term pill use in high-risk groups: more lung cancer and deaths. Preformed vitamin A (retinol) is different and can cause serious illness in large amounts.
Animal. Not reviewed.
High dose or long term signals. Lung cancer and death in smokers and asbestos workers with 20 to 30 mg a day over 4 to 8 years (ATBC, CARET). No harm detected over about 12 years at 50 mg on alternate days in male doctors, or in women over a limited period. These are trial figures, not advice.
Overdose response. Not described in the sources read beyond skin yellowing.
Genotoxicity. Not researched.
Contamination and label accuracy of beta-carotene supplements were not researched for this page.
Beta-carotene in multivitamins and eye formulas. Beta-carotene is an ingredient in some multivitamins and in the original AREDS eye formula (NEI), so a person can take it without realising. The AREDS2 formula does not contain it. 19 18
| Body | Action | Date |
|---|---|---|
| US Preventive Services Task Force (JAMA) (United States) | Recommends against beta-carotene or vitamin E supplements to prevent cardiovascular disease or cancer in non-pregnant adults (grade D). Concluded with moderate certainty that the harms of beta-carotene outweigh the benefits. source | 2022-06-21 |
| NCCIH (US National Center for Complementary and Integrative Health) (United States) | Says current evidence does not support antioxidant supplements preventing cancer or cardiovascular disease, and that high-dose beta-carotene may increase lung cancer risk and cardiovascular death, mainly in smokers and people with asbestos exposure. Advises checking with providers before use during cancer treatment. source | 2023-07 |
| National Eye Institute (US) (United States) | Says current and former smokers should use the AREDS2 formula and avoid the AREDS formula with beta-carotene, which increases lung cancer risk. source | 2025-10-22 |
| MedlinePlus (US National Library of Medicine) (United States) | Says beta-carotene supplements do not reduce cancer risk and may increase cancer risk in current and former smokers and asbestos workers; large amounts of beta-carotene will not make you seriously ill but can turn skin yellow or orange. source | 2025-01-21 |
| NHS / UK Department of Health and Social Care (United Kingdom) | Page on vitamin A (retinol). Advises older men and post-menopausal women to keep vitamin A from food and supplements together to an average of 1.5 mg a day or less. This limit is for vitamin A (retinol); the page does not give a limit for beta-carotene. source | 2020-08-03 |
When to get medical help
- A cough that does not go away, coughing up blood, chest pain or breathlessness, especially in a smoker, former smoker or someone who has worked with asbestos: see a doctor promptly (general medical advice; not specific to beta-carotene).
- A sudden change in vision, such as blurred or distorted central vision: see an eye doctor straight away.
- Someone, especially a child, has swallowed a large amount of vitamin A or multivitamin tablets: call poison control or emergency services.
- Yellow or orange skin alone is usually harmless in beta-carotene users, but if the whites of the eyes also turn yellow, see a doctor (this can be a sign of a different problem).
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is beta-carotene?
What foods have beta-carotene?
Do beta-carotene pills raise lung cancer risk?
Are beta-carotene supplements safe for non-smokers?
Does beta-carotene prevent cancer or heart disease?
Is beta-carotene in eye vitamins?
Does beta-carotene help with macular degeneration?
Does beta-carotene help with cataract?
No. A Cochrane review of 9 trials found no evidence that antioxidant vitamins, including beta-carotene, lower the risk of cataract or cataract surgery.
Can beta-carotene turn your skin orange?
Does beta-carotene interact with other supplements or medicines?
In CARET it was given with vitamin A, and the harm cannot be separated. NCCIH reports one study in which a combination including beta-carotene reduced the cholesterol-lowering effect of two drugs, and advises checking with your cancer team before antioxidants during treatment. Ask a pharmacist.
Is beta-carotene safe in pregnancy or for children?
No source read gave advice on beta-carotene pills in pregnancy or for children. MedlinePlus warns that large amounts of preformed vitamin A can cause birth defects and that children are more sensitive to vitamin A. Ask a doctor or pharmacist before any vitamin A or beta-carotene product.
Explore by health goal
Preventive WellnessCellular ProtectionHealthy AgingImmune SupportHeart HealthMemory SupportBrain Health
Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-26
- Last substantive update
- 2026-10-26
- How we research
- We started from our existing beta-carotene summary, read pages from NCCIH, the National Eye Institute, MedlinePlus and the NHS, re-checked food values in saved USDA FoodData Central data, and re-read PubMed abstracts for the trials and reviews. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. Trials of supplements may have manufacturer links not stated in abstracts.
Sources 22
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Age-Related Eye Disease Study 2 Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial.. JAMA. 2013. PMID 23644932. DOI 10.1001/jama.2013.4997. (abstract)
- Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.. Arch Ophthalmol. 2001. PMID 11594942. DOI 10.1001/archopht.119.10.1417. (abstract)
- 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. PMID 8127329. DOI 10.1056/NEJM199404143301501. (abstract)
- Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases.. Cochrane Database Syst Rev. 2012. PMID 22419320. DOI 10.1002/14651858.CD007176.pub2. (abstract)
- Cortes-Jofre M, Rueda JR, Asenjo-Lobos C, Madrid E, Bonfill Cosp X. Drugs for preventing lung cancer in healthy people.. Cochrane Database Syst Rev. 2020. PMID 32130738. DOI 10.1002/14651858.CD002141.pub3. (abstract)
- Druesne-Pecollo N, Latino-Martel P, Norat T, Barrandon E, Bertrais S, Galan P et al.. Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials.. Int J Cancer. 2010. PMID 19876916. DOI 10.1002/ijc.25008. (abstract)
- Evans JR, Lawrenson JG. Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration.. Cochrane Database Syst Rev. 2023. PMID 37702300. DOI 10.1002/14651858.CD000254.pub5. (abstract)
- Goodman GE, Thornquist MD, Balmes J, Cullen MR, Meyskens FL Jr, Omenn GS et al.. The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements.. J Natl Cancer Inst. 2004. PMID 15572756. DOI 10.1093/jnci/djh320. (abstract)
- Grodstein F, Kang JH, Glynn RJ, Cook NR, Gaziano JM. A randomized trial of beta carotene supplementation and cognitive function in men: the Physicians' Health Study II.. Arch Intern Med. 2007. PMID 17998490. DOI 10.1001/archinte.167.20.2184. (abstract)
- Hennekens CH, Buring JE, Manson JE, Stampfer M, Rosner B, Cook NR et al.. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease.. N Engl J Med. 1996. PMID 8602179. DOI 10.1056/NEJM199605023341801. (abstract)
- Lee IM, Cook NR, Manson JE, Buring JE, Hennekens CH. Beta-carotene supplementation and incidence of cancer and cardiovascular disease: the Women's Health Study.. J Natl Cancer Inst. 1999. PMID 10601381. DOI 10.1093/jnci/91.24.2102. (abstract)
- Mathew MC, Ervin AM, Tao J, Davis RM. Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract.. Cochrane Database Syst Rev. 2012. PMID 22696344. DOI 10.1002/14651858.CD004567.pub2. (abstract)
- Omenn GS, Goodman GE, Thornquist MD, Balmes J, Cullen MR, Glass A et al.. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease.. N Engl J Med. 1996. PMID 8602180. DOI 10.1056/NEJM199605023341802. (abstract)
- US Preventive Services Task Force; Mangione CM, Barry MJ, Nicholson WK et al.. Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement.. JAMA. 2022. PMID 35727271. DOI 10.1001/jama.2022.8970. (abstract)
- Virtamo J, Pietinen P, Huttunen JK, Korhonen P, Malila N, Virtanen MJ et al.. Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up.. JAMA. 2003. PMID 12876090. DOI 10.1001/jama.290.4.476. (abstract)
- Virtamo J, Taylor PR, Kontto J, Mannisto S, Utriainen M, Weinstein SJ et al.. Effects of alpha-tocopherol and beta-carotene supplementation on cancer incidence and mortality: 18-year postintervention follow-up of the Alpha-tocopherol, Beta-carotene Cancer Prevention Study.. Int J Cancer. 2014. PMID 24338499. DOI 10.1002/ijc.28641. (abstract)
- . MedlinePlus Medical Encyclopedia: Vitamin A (review date 2025-01-21). . . (full-text)
- . NCCIH (US National Center for Complementary and Integrative Health): Antioxidants - In Depth (page 'Last Updated: July 2023'). . . (full-text)
- . National Eye Institute: About AREDS and AREDS2 (page last updated 2025-10-22). . . (full-text)
- . NHS: Vitamins and minerals - Vitamin A (page last reviewed 2020-08-03). . . (full-text)
- . NIH Office of Dietary Supplements: Vitamin A and Carotenoids fact sheet for health professionals. . . (not-read)
- . USDA FoodData Central, SR Legacy (April 2018 release): beta-carotene content of common foods. . . (full-text)
Where to buy
Check the label first. Whatever you buy, look for these:
- The amount of the active ingredient per serving, not just the front-label claim
- A third-party testing mark (USP, NSF or ConsumerLab)
- Other ingredients and allergens
- Ask a pharmacist about interactions with your medicines
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
Support our free guides: as an Amazon Associate we earn from qualifying purchases. Full disclosure.
