Home Ingredients Beta-Carotene
Hair, Skin & Nails

Beta-Carotene

Provitamin A carotenoid (β,β-carotene)
Evidence Level
Limited
6 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

Beta-carotene is an orange-red carotenoid pigment found in carrots, sweet potatoes and leafy greens, and sold as a synthetic or algal supplement. The body converts it into vitamin A in the intestine, and conversion rates vary between people. NIH counts 2 micrograms of supplemental beta-carotene or 12 micrograms of food beta-carotene as 1 microgram of vitamin A (RAE). Unlike preformed vitamin A, beta-carotene is not known to cause birth defects and has no set upper limit, but the Food and Nutrition Board advises against beta-carotene supplements for the general population except to prevent vitamin A deficiency. In large trials, 20 to 30 mg a day raised lung cancer in smokers and asbestos-exposed workers, and current and former smokers should avoid high-dose supplements. In a small placebo-controlled trial, 24 mg a day for 12 weeks lowered skin redness after UV light, while a shorter high-dose trial found no protection.

Studied Dose Trials: 24 mg a day (algal) for 12 weeks for skin redness; 90 mg a day for 23 days (no protection); 20 mg a day (ATBC) and 30 mg a day with retinyl palmitate (CARET) for years in smokers; 50 mg on alternate days for 12 years; 15 mg a day within the AREDS formula.
Active Compound Beta-carotene (a tetraterpenoid provitamin A carotenoid), as synthetic or algal (Dunaliella salina) material; converted to vitamin A in the intestine by beta-carotene monooxygenase type 1 (BCMO1).

Benefits

Provitamin A source of vitamin A

The body converts beta-carotene into vitamin A in the intestine, and conversion rates may vary with genetics. NIH counts 2 micrograms of supplemental beta-carotene or 12 micrograms of food beta-carotene as 1 microgram of vitamin A (RAE) and reports absorption from supplements of 8.7% to 65%. No upper limit has been set for beta-carotene.

Supported by Trial 1, Trial 4

Skin response to UV light

In a placebo-controlled trial in fair-skinned adults, 24 mg a day of algal beta-carotene for 12 weeks lowered skin redness after UV light compared with placebo. A pooled analysis of 7 studies found protection only after at least 10 weeks of use, and 90 mg a day for 23 days gave no protection versus placebo. The trial authors note the protection is not comparable to a high SPF sunscreen.

Supported by Trial 1, Trial 2

Antioxidant role and long-term supplement trials

Beta-carotene quenches singlet oxygen and free radicals in lab systems. In people, 50 mg on alternate days for 12 years neither helped nor harmed healthy male physicians, and a Cochrane review of trials with low risk of bias found more deaths with beta-carotene supplements (26 trials, relative risk 1.05).

Supported by Trial 5, Trial 4

Eye health within a multi-nutrient formula

In older adults at high risk of advanced AMD, a daily formula of beta-carotene 15 mg, vitamins C and E and zinc slowed progression versus placebo, while the antioxidants alone did not reach significance. NIH reports that AREDS2 found beta-carotene was not needed for this effect and saw more lung cancers with it, mostly in former smokers, so current formulas use lutein and zeaxanthin.

Supported by Trial 6, Trial 5

Mechanism of action

1

Conversion to vitamin A

NIH describes conversion of provitamin A carotenoids into vitamin A in the intestine by the enzyme beta-carotene monooxygenase type 1 (BCMO1), with genetic variability in conversion rates. NIH counts 2 micrograms of supplemental and 12 micrograms of food beta-carotene as 1 microgram RAE, so food beta-carotene yields less vitamin A per microgram.

2

Quenching of singlet oxygen and free radicals

Beta-carotene is described as a quencher of excited species such as singlet oxygen and free radicals, the proposed basis for its effect on UV-induced skin redness. In supplemented adults, serum beta-carotene and skin carotenoid levels rose over 12 weeks while they stayed flat with placebo.

3

Alcohol interaction and high-dose findings

A review reports that alcohol interferes with the conversion of beta-carotene to retinol, that beta-carotene combined with alcohol caused liver toxicity, and that in smokers who also drink, beta-carotene supplementation was linked with lung cancer. The ATBC and CARET trials did not establish why large doses raised lung cancer in smokers.

Clinical trials

1
Algal beta-carotene and UV-induced skin redness
PubMed

Placebo-controlled, parallel-group trial: 24 mg a day of beta-carotene from an algal source, a 24 mg carotenoid blend (beta-carotene, lutein and lycopene, 8 mg each) or placebo for 12 weeks, 12 people with skin type II per group; funding is not stated in the abstract. (Heinrich et al. 2003, J Nutr)

36 healthy adults aged 22 to 55 with skin type II (12 men, 24 women; 12 per group) in Germany.

Redness 24 hours after a solar simulator dose was lower and was significantly below baseline after 12 weeks in both carotenoid groups; no changes occurred in the placebo group. The abstract does not report a direct test against placebo. Serum beta-carotene rose three to fourfold. The authors note the protection is not comparable to a high SPF sunscreen.

2
High-dose beta-carotene and the sunburn reaction
PubMed

Double-blind, placebo-controlled trial at the USDA Human Nutrition Research Center on Aging, Tufts University: a single 120 mg dose in diet-restricted volunteers, or 90 mg a day for 23 days on a standard diet, then one solar-simulated light exposure at 3 times the minimal erythema dose; PubMed lists no research support type (Garmyn et al. 1995, Exp Dermatol)

Healthy volunteers; group sizes are not given in the abstract.

Beta-carotene raised plasma and tissue beta-carotene compared with pretreatment and placebo, but gave no clinically or histologically detectable protection against the sunburn reaction 24 hours after exposure.

3
Beta-carotene and lung cancer in male smokers (ATBC)
PubMed

Randomized, double-blind, placebo-controlled 2 by 2 factorial trial of alpha-tocopherol 50 mg a day, beta-carotene 20 mg a day, both, or placebo for 5 to 8 years; PubMed lists US Public Health Service support (Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group 1994, N Engl J Med)

29,133 male smokers aged 50 to 69 in southwestern Finland.

Among 876 new lung cancers, incidence was 18% higher in men given beta-carotene than in men not given it (95% CI 3 to 36%), and total mortality was 8% higher (95% CI 1 to 16%), mainly from lung cancer and ischemic heart disease. Beta-carotene had little or no effect on other cancers.

4
Beta-carotene plus retinyl palmitate in smokers and asbestos workers (CARET follow-up)
PubMed

Post-intervention follow-up through 2001 of a randomized, double-blind, placebo-controlled trial of 30 mg beta-carotene plus 25,000 IU retinyl palmitate a day, stopped early in January 1996; PubMed lists US Public Health Service support (Goodman et al. 2004, J Natl Cancer Inst)

18,314 people at high risk for lung cancer because of a smoking history or asbestos exposure.

At the early stop, the active group had 28% more lung cancer and 17% more deaths than placebo. After supplements stopped, relative risks were 1.12 (95% CI 0.97 to 1.31) for lung cancer and 1.08 (0.99 to 1.17) for all-cause mortality, no longer statistically significant; planned subgroup analyses placed the excess lung cancer risk mainly in women.

5
Long-term beta-carotene in male physicians (Physicians' Health Study)
PubMed

Randomized, double-blind, placebo-controlled trial of 50 mg beta-carotene on alternate days, 1982 to 1995 (about 12 years); PubMed lists US Public Health Service support (Hennekens et al. 1996, N Engl J Med)

22,071 US male physicians aged 40 to 84; 11% current and 39% former smokers at baseline.

No difference from placebo in malignant neoplasms (1273 vs 1293; relative risk 0.98, 95% CI 0.91 to 1.06), lung cancer (82 vs 88), deaths from any cause (979 vs 968) or cardiovascular deaths (338 vs 313), including among current and former smokers.

6
AREDS formula containing beta-carotene and vision outcomes
PubMed

11-center, double-masked, placebo-controlled trial of antioxidants (vitamin C 500 mg, vitamin E 400 IU, beta-carotene 15 mg), zinc 80 mg with copper 2 mg, both, or placebo; average follow-up 6.3 years; beta-carotene was one part of a combination; PubMed lists US and non-US government support (Age-Related Eye Disease Study Research Group 2001, Arch Ophthalmol)

3,640 people aged 55 to 80 with drusen or pigment changes, or advanced age-related macular degeneration or vision loss in one eye.

Versus placebo, antioxidants plus zinc lowered the odds of advanced AMD (OR 0.72, 99% CI 0.52 to 0.98) and of losing 15 or more letters of acuity (OR 0.73, 99% CI 0.54 to 0.99). Antioxidants alone did not reach significance (OR 0.80, 99% CI 0.59 to 1.09).

Side effects and drug interactions

Common Potential side effects

Lung cancer in smokers: in the ATBC trial, 20 mg a day raised lung cancer incidence by 18% and total mortality by 8% in male smokers, and in CARET, 30 mg a day with retinyl palmitate raised lung cancer (relative risk 1.28) in smokers, former smokers and asbestos-exposed workers. NIH states these results suggest large supplemental doses have harmful effects in current or former smokers and asbestos-exposed workers, and reports more lung cancers with 15 mg a day in AREDS2 (23 vs 11, mostly former smokers).
Mortality: a Cochrane review found more deaths with beta-carotene supplements in trials with low risk of bias (26 trials, relative risk 1.05, 95% CI 1.01 to 1.09). In the Physicians' Health Study, 50 mg on alternate days for 12 years showed neither benefit nor harm.
Yellow-orange skin: NIH describes carotenodermia from long-term excess beta-carotene as harmless and reversible by stopping intake. In a 42-day trial in 30 men, definite carotenodermia appeared only with 30 mg a day of purified beta-carotene, not with 12 mg a day or carotene-rich vegetables, and lasted up to more than 6 weeks after stopping.

Important Drug interactions

Simvastatin plus niacin: in a 12-month randomized trial in 153 people with coronary artery disease and low HDL, an antioxidant combination of vitamins E and C, beta-carotene and selenium blunted the HDL response to simvastatin plus niacin (HDL2 cholesterol rose 42% without antioxidants versus 0% with them). Beta-carotene was not tested alone.
Orlistat: in 48 healthy volunteers, orlistat reduced absorption of a single beta-carotene dose by about one third (study by authors at the drug's maker). NIH notes orlistat can lower absorption of vitamin A, other fat-soluble vitamins and beta-carotene, and the makers of Alli and Xenical recommend a multivitamin containing them.
Smoking and asbestos exposure: large supplemental doses raised lung cancer in the ATBC and CARET trials (see side effects).
Alcohol: a review reports that alcohol interferes with the conversion of beta-carotene to retinol and that beta-carotene combined with alcohol caused liver toxicity; in smokers who also drink, beta-carotene supplementation was linked with lung cancer.

Featured in these supplement guides

Eye Health→Skin Health & Anti-Aging→

More Hair, Skin & Nails Ingredients

Hair, Skin & Nails
Niacin
Niacin (vitamin B3) is an essential water-soluble vitamin central to energy metabolism, DN…
Hair, Skin & Nails
Bovine Collagen
Bovine collagen is hydrolyzed collagen sourced from cow hide, bone, and cartilage. It is o…
Hair, Skin & Nails
Marine Collagen
Marine collagen is hydrolyzed collagen made from fish skin and scales, mainly type I colla…
Hair, Skin & Nails
Astaxanthin
Astaxanthin is a red-orange carotenoid antioxidant. It is naturally produced by the microa…

Explore Other Ingredients

Bone Health
Collagen
Collagen is the main structural protein of skin, bone, cartilage, tendons and ligaments. S…
Hair, Skin & Nails
Hyaluronic Acid
Hyaluronic acid is a naturally occurring substance in the body, primarily found in connect…
Immune Support
Vitamin C
Vitamin C (L-ascorbic acid) is a water-soluble vitamin that humans cannot make, so it must…

Related articles from our blog

📝 Article
Astaxanthin: The ‘6,000 Times Vitamin C’ Claim vs the Human Trials
Astaxanthin is the red pigment that makes salmon pink, shrimp orange and flamingos rosy. As a supplement, it comes with…
November 1, 2026
📝 Article
Vitamin A: Retinol vs Beta-Carotene, and Why Smokers Should Be Careful
Vitamin A on a supplement label can mean two very different things. It can be preformed vitamin A (retinol or retinyl es…
October 31, 2026
📝 Article
Lutein and Zeaxanthin for Eye Health: The Evidence
Lutein and zeaxanthin are the two carotenoids your body concentrates in the center of the retina, where they form a yell…
October 7, 2026

Frequently asked questions about Beta-Carotene

What is Beta-Carotene used for?

Beta-carotene is mainly used as a provitamin A source: NIH lists it among the usual forms of vitamin A in multivitamins and stand-alone supplements. Small placebo-controlled trials also tested it for skin redness after UV light, with benefit after 12 weeks but not after 23 days. The Food and Nutrition Board advises against beta-carotene supplements for the general population except as a provitamin A source to prevent vitamin A deficiency.

How does beta-carotene compare with preformed vitamin A?

NIH notes that the upper limit for vitamin A applies only to preformed vitamin A (retinol and its esters), that no upper limit has been set for beta-carotene, and that unlike preformed vitamin A, beta-carotene is not known to cause birth defects or reproductive toxicity. NIH also notes that experts advise women who are or might be pregnant, and those who are lactating, not to take more than 3,000 micrograms RAE a day of vitamin A supplements. Beta-carotene supplements still carry risks: 20 to 30 mg a day raised lung cancer in smokers and asbestos-exposed workers in the ATBC and CARET trials.

What is the recommended dosage of Beta-Carotene?

There is no separate recommended intake for beta-carotene. NIH lists the vitamin A RDA as 900 micrograms RAE for men and 700 for women, with 2 micrograms of supplemental beta-carotene counted as 1 microgram RAE. The Food and Nutrition Board advises against beta-carotene supplements for the general population except to prevent vitamin A deficiency. The skin redness trial used 24 mg a day for 12 weeks, and 20 to 30 mg a day raised lung cancer in smokers.

Is Beta-Carotene safe, and does it have side effects?

In the ATBC trial, 20 mg a day raised lung cancer incidence by 18% and total mortality by 8% in male smokers, and in CARET, 30 mg a day with retinyl palmitate raised lung cancer in smokers and asbestos-exposed workers. A Cochrane review found more deaths with beta-carotene supplements in trials with low risk of bias. In healthy male physicians, 50 mg on alternate days for 12 years showed neither benefit nor harm. Long-term excess can turn the skin yellow-orange (carotenodermia), which NIH calls harmless and reversible. If you smoke or used to smoke, avoid high-dose beta-carotene supplements; in the AREDS2 eye trial, 15 mg a day was linked to more lung cancers, mostly in former smokers.

What is Beta-Carotene?

Beta-carotene is an orange-red carotenoid pigment found in carrots, sweet potatoes and leafy greens, and sold as a synthetic or algal supplement. The body converts it into vitamin A in the intestine, and conversion rates vary between people.

Does Beta-Carotene interact with any medications?

Possible interactions include: Simvastatin plus niacin: in a 12-month randomized trial in 153 people with coronary artery disease and low HDL, an antioxidant combination of vitamins E and C, beta-carotene and selenium blunted the HDL response to simvastatin plus niacin (HDL2 cholesterol rose 42% without antiox… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Beta-Carotene?

NutraSmarts rates the evidence for Beta-Carotene as Limited (2 out of 5). It is backed by 6 study summaries and 14 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(14 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. 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;330(15):1029-35. doi: 10.1056/NEJM199404143301501.PubMedUsed to support: ATBC randomized, placebo-controlled trial in 29,133 male smokers aged 50 to 69 in Finland: 20 mg a day of beta-carotene for 5 to 8 years was followed by an 18% higher lung cancer incidence (95% CI 3 to 36%) and 8% higher total mortality (95% CI 1 to 16%), mainly from lung cancer and ischemic heart disease; little or no effect on other cancers.
  2. Omenn GS, Goodman GE, Thornquist MD, Balmes J, Cullen MR, Glass A, Keogh JP, Meyskens FL, Valanis B, Williams JH, Barnhart S, Hammar S. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996;334(18):1150-5. doi: 10.1056/NEJM199605023341802.PubMedUsed to support: CARET randomized, placebo-controlled trial in 18,314 smokers, former smokers and asbestos-exposed workers: 30 mg beta-carotene plus 25,000 IU retinyl palmitate a day raised lung cancer (relative risk 1.28, 95% CI 1.04 to 1.57) and death from any cause (1.17, 1.03 to 1.33); the trial was stopped 21 months early.
  3. Goodman GE, Thornquist MD, Balmes J, Cullen MR, Meyskens FL Jr, Omenn GS, Valanis B, Williams JH Jr. 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;96(23):1743-50. doi: 10.1093/jnci/djh320.PubMedUsed to support: CARET follow-up through 2001 after supplements stopped: relative risks were 1.12 (95% CI 0.97 to 1.31) for lung cancer and 1.08 (0.99 to 1.17) for all-cause mortality, above 1.0 but no longer statistically significant; planned subgroup analyses placed the excess lung cancer risk mainly in women.
  4. Hennekens CH, Buring JE, Manson JE, Stampfer M, Rosner B, Cook NR, Belanger C, LaMotte F, Gaziano JM, Ridker PM, Willett W, Peto R. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med. 1996;334(18):1145-9. doi: 10.1056/NEJM199605023341801.PubMedUsed to support: Physicians' Health Study: in 22,071 US male physicians (11% current and 39% former smokers), 50 mg beta-carotene on alternate days for 12 years produced no difference from placebo in malignant neoplasms (relative risk 0.98), cardiovascular disease or deaths from any cause, including among smokers.
  5. 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;2012(3):CD007176. doi: 10.1002/14651858.CD007176.pub2.PubMedUsed to support: Cochrane systematic review of 78 randomized trials: in trials with low risk of bias, beta-carotene supplements increased all-cause mortality (26 trials, relative risk 1.05, 95% CI 1.01 to 1.09); the authors found no evidence supporting antioxidant supplements for primary or secondary prevention.
  6. 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;119(10):1417-36. doi: 10.1001/archopht.119.10.1417.PubMedUsed to support: AREDS randomized trial in 3,640 people aged 55 to 80: antioxidants (vitamin C 500 mg, vitamin E 400 IU, beta-carotene 15 mg) plus zinc lowered the odds of advanced AMD versus placebo (OR 0.72, 99% CI 0.52 to 0.98); antioxidants alone did not reach significance (OR 0.80, 99% CI 0.59 to 1.09). Beta-carotene was tested only as part of a combination.
  7. Cheung MC, Zhao XQ, Chait A, Albers JJ, Brown BG. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol. 2001;21(8):1320-6. doi: 10.1161/hq0801.095151.PubMedUsed to support: Randomized trial in 153 people with coronary artery disease and low HDL over 12 months: an antioxidant combination (vitamins E and C, beta-carotene and selenium) blunted the HDL response to simvastatin plus niacin (HDL2 cholesterol rose 42% without antioxidants versus 0% with them). Beta-carotene was not tested alone.
  8. Heinrich U, Gärtner C, Wiebusch M, Eichler O, Sies H, Tronnier H, Stahl W. Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema. J Nutr. 2003;133(1):98-101. doi: 10.1093/jn/133.1.98.PubMedUsed to support: Placebo-controlled parallel trial in 36 adults with skin type II (12 per group): 24 mg a day of beta-carotene from an algal source for 12 weeks lowered redness 24 hours after a solar simulator dose to significantly below baseline by 12 weeks, while the placebo group did not change; the abstract does not report a direct test against placebo. A 24 mg carotenoid blend had a similar effect.
  9. Köpcke W, Krutmann J. Protection from sunburn with beta-Carotene--a meta-analysis. Photochem Photobiol. 2008;84(2):284-8. doi: 10.1111/j.1751-1097.2007.00253.x.PubMedUsed to support: Meta-analysis of 7 human studies of oral beta-carotene and sunburn: supplementation was protective, and study duration drove the effect size; protection required at least 10 weeks of use, rising by about 0.5 standard deviations with each further month.
  10. Garmyn M, Ribaya-Mercado JD, Russel RM, Bhawan J, Gilchrest BA. Effect of beta-carotene supplementation on the human sunburn reaction. Exp Dermatol. 1995;4(2):104-11. doi: 10.1111/j.1600-0625.1995.tb00231.x.PubMedUsed to support: Double-blind, placebo-controlled trial: a single 120 mg dose or 90 mg a day for 23 days raised plasma and skin beta-carotene but gave no clinical or histologic protection against a sunburn reaction from 3 times the minimal erythema dose.
  11. Micozzi MS, Brown ED, Taylor PR, Wolfe E. Carotenodermia in men with elevated carotenoid intake from foods and beta-carotene supplements. Am J Clin Nutr. 1988;48(4):1061-4. doi: 10.1093/ajcn/48.4.1061.PubMedUsed to support: Randomized 42-day study in 30 men (5 per group): definite carotenodermia (yellowing of the skin) appeared only with 30 mg a day of purified beta-carotene, not with 12 mg a day, carrots, broccoli, tomato juice or placebo; it began after 25 to 42 days and lasted 14 to more than 42 days after stopping.
  12. Zhi J, Melia AT, Koss-Twardy SG, Arora S, Patel IH. The effect of orlistat, an inhibitor of dietary fat absorption, on the pharmacokinetics of beta-carotene in healthy volunteers. J Clin Pharmacol. 1996;36(2):152-9. doi: 10.1002/j.1552-4604.1996.tb04180.x.PubMedUsed to support: Randomized crossover study in 48 healthy volunteers by authors at Hoffmann-La Roche (the maker of orlistat): orlistat 120 mg three times a day reduced absorption of a single 30 to 120 mg beta-carotene dose by about one third.
  13. Leo MA, Lieber CS. Alcohol, vitamin A, and beta-carotene: adverse interactions, including hepatotoxicity and carcinogenicity. Am J Clin Nutr. 1999;69(6):1071-85. doi: 10.1093/ajcn/69.6.1071.PubMedUsed to support: Review: alcohol interferes with the conversion of beta-carotene to retinol, beta-carotene combined with alcohol caused liver toxicity, and in smokers who also drink, beta-carotene supplementation was linked with lung cancer; the authors describe a narrowing of the therapeutic window for beta-carotene in drinking populations.
  14. Office of Dietary Supplements, National Institutes of Health. Vitamin A and Carotenoids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. 2025;Updated March 10, 2025; accessed 2026..SourceUsed to support: Not PubMed-indexed; official NIH fact sheet (read). Provitamin A carotenoids are converted to vitamin A in the intestine by BCMO1, with genetic variability in conversion; 1 microgram RAE equals 2 micrograms of supplemental or 12 micrograms of food beta-carotene; supplement beta-carotene absorption ranges from 8.7% to 65%. Beta-carotene is not known to be teratogenic; carotenodermia is harmless and reversible. No upper limit is set for beta-carotene, and the FNB advises against beta-carotene supplements for the general population except as a provitamin A source to prevent vitamin A deficiency. ATBC and CARET suggest large supplemental doses harm current or former smokers and asbestos-exposed workers; in AREDS2 more lung cancers occurred with beta-carotene (23 vs 11, mostly former smokers) and beta-carotene was not required for the AREDS effect. Orlistat can lower beta-carotene absorption.