VITAMINS & SUPPLEMENTS · GUIDE
Antioxidants, Smoking, Alcohol and Higher-Risk Groups
What the ATBC, CARET and AREDS2 trials found about beta-carotene in smokers, former smokers, asbestos-exposed workers and heavier drinkers, and who else should ask a clinician first.
Content last updated . This page has not been medically reviewed.
Back to AntioxidantsIf you smoke, used to smoke or worked with asbestos, ask a clinician or pharmacist before taking any product that contains beta-carotene. That includes multivitamins and eye-health formulas, so read the label. This page is information only.
What each trial found
Evidence label for all rows: evidence of harm in a stated group. These were study amounts, not advice.| Trial | Who | Form and amount | Duration | Finding | Source, year |
|---|---|---|---|---|---|
| ATBC | 29,133 male smokers in Finland, aged 50 to 69 | Beta-carotene 20 mg a day; alpha-tocopherol 50 mg a day; both; or placebo | 5 to 8 years | 18% higher lung cancer in beta-carotene groups; no reduction from alpha-tocopherol; more deaths from hemorrhagic stroke with alpha-tocopherol | NEJM, 1994 [3] |
| CARET | 18,314 smokers, former smokers and asbestos-exposed workers | Beta-carotene 30 mg plus retinol 25,000 IU (as retinyl palmitate) a day | Average 4 years | Lung cancer relative risk 1.28; relative risk of death from any cause 1.17 and from lung cancer 1.46; stopped 21 months early | NEJM, 1996 [4] |
| AREDS2 | 4,203 people aged 50 to 85 with age-related macular degeneration | AREDS formulas with or without beta-carotene | Median 5 years | Lung cancers 2.0% with beta-carotene vs 0.9% without, mostly in former smokers (nominal P = .04) | JAMA, 2013 [5] |
Because CARET combined beta-carotene with retinol, its result cannot be assigned to beta-carotene alone. [4] ATBC gave beta-carotene by itself, and the effect was seen there too. [3]
What about the eye-health formulas?
The National Eye Institute (NEI) states that current and former smokers should use the AREDS2 formula, which has no beta-carotene, and avoid the original AREDS formula with beta-carotene, which it says increases lung cancer risk. [6] AREDS2 excluded current smokers from receiving the beta-carotene formulation. [6] Whether such a formula suits you is a decision for your eye doctor. See Antioxidants and Eye Disease and carotenoids.Alcohol
A later ATBC analysis looked at subgroups. The beta-carotene effect on lung cancer was relative risk 1.35 in men drinking at least 11 g of ethanol a day (just under one drink) versus 1.03 in lighter drinkers. [7] The authors said the effects "appeared stronger, but not substantially different," so this is a hint from a subgroup analysis, not a proven interaction. [7] Alcohol and other antioxidant supplements are not described in the sources we read. Proper evidence not found: we looked in NCCIH, MedlinePlus and PubMed for alcohol-specific antioxidant warnings and found only this subgroup analysis.Food is not the same as a supplement
MedlinePlus notes that eating food sources of beta-carotene may reduce cancer risk, while supplements do not. [2] NCI also warns that results from observational studies of diet should be viewed with caution because they cannot control for bias. [8] Do not assume a finding about carrots applies to a pill, or the reverse.Other higher-risk groups
- People with cancer: antioxidants may reduce the effectiveness of some treatments; tell your oncology team. [1] See Antioxidants and Cancer.
- Hemochromatosis: vitamin C supplements can worsen iron overload. [1]
- People on blood thinners: high-dose vitamin E raises bleeding concerns. [1]
- Pregnancy, surgery, kidney and liver conditions: see pregnancy and children and surgery, kidney and liver.
All-cause mortality: a Cochrane review of 78 trials found beta-carotene and vitamin E seemed to increase mortality, and that there was no evidence to support antioxidant supplements for prevention. [9]
Frequently asked questions
Should smokers take beta-carotene supplements?
Trials found more lung cancer with them, and NCCIH reports the strongest evidence of harm in smokers. Ask a clinician first. [3][1]
Does stopping smoking remove the concern?
AREDS2 found more lung cancers with beta-carotene, mostly in former smokers, so former smokers are also named by the NEI. [5][6]
Is beta-carotene from vegetables risky?
MedlinePlus separates food sources from supplements. [2]
Does drinking alcohol change the risk?
A subgroup analysis of ATBC suggested a stronger effect in heavier drinkers, but the difference was not substantial. [7]
Do AREDS2 supplements contain beta-carotene?
The NEI describes AREDS2 formulas without beta-carotene, and the original AREDS formula with it. [6]
References
- NCCIH, Antioxidant Supplements: What You Need To Know (July 2023). Read 2026-10-23.
- MedlinePlus, Vitamin A. Read 2026-10-23.
- ATBC 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). Read 2026-10-23.
- Omenn et al., Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease, CARET (N Engl J Med 1996). Read 2026-10-23.
- AREDS2 Research Group, Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: AREDS2 (JAMA 2013). Read 2026-10-23.
- National Eye Institute, About AREDS and AREDS2 (updated Oct 22, 2025). Read 2026-10-23.
- Albanes et al., Alpha-tocopherol and beta-carotene supplements and lung cancer incidence in the ATBC study: effects of base-line characteristics and study compliance (J Natl Cancer Inst 1996). Read 2026-10-23.
- National Cancer Institute, Antioxidants and Cancer Prevention. Read 2026-10-23.
- Bjelakovic et al., Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases (Cochrane Database Syst Rev 2012). Read 2026-10-23.