Supplement
Beta-carotene is the orange plant pigment in carrots and sweet potatoes, which the body can turn into vitamin A and which also works as an antioxidant. People mostly look at it for sun sensitivity such as polymorphous light eruption, where the evidence is moderate and studies found mixed but partly positive results. Large trials found no drop in melanoma or other skin cancers, and in smokers it was linked to higher lung cancer risk.
- Updated
- How we grade
- 4 studies cited
- Best evidence
- Grade D
- Conditions studied
- 4
- Outcomes
- 5
- Graded outcomes
- 0005
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Lung Cancer Incidence (Smokers) HARMFUL: ATBC (PMID: 8901854) showed 18% increase; CARET showed 28% increase. Meta-analysis: 24% increased risk in smokers | Worsens (the measure goes up) | Moderate effect | 47,447 people |
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Overall Cancer Risk No benefit in 12-year Physicians' Health Study (50mg every other day) in non-smokers | NoneNo effect | 50,000 people |
Cardiovascular Disease
- CVD Mortality: worsens
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| CVD Mortality CARET: 26% increased CVD mortality; meta-analysis shows increased CVD risk in supplementation trials | Worsens (the measure goes up) | Small effect | 40,000 people |
Skin Cancer
- Non-Melanoma Skin Cancer Risk
- Melanoma Risk
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Non-Melanoma Skin Cancer Risk No significant reduction in risk compared to placebo (large RCTs) | NoneNo effect | 30,000 people | ||||
| Melanoma Risk No effect on melanoma risk (meta-analysis of RCTs: RR 0.98) | NoneNo effect | 15,000 people |
Key findings
- Lung Cancer Incidence (Smokers)Worsens (the measure goes up)
- Overall Cancer Risk
- CVD MortalityWorsens (the measure goes up)
Safety notes in the studies
- Meta-analysis: 24% increased risk in smokers
- CARET: 26% increased CVD mortality; meta-analysis shows increased CVD risk in supplementation trials
- No significant reduction in risk compared to placebo (large RCTs)
Studies cited
4 studies from PubMed
- Beta-carotene and lung cancer in smokers: review of hypotheses and status of research
- 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
- Effects of a Combination of Beta Carotene and Vitamin A on Lung Cancer and Cardiovascular Disease (CARET Trial)
- Alpha-Tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance