The claimEvidence A · guideline-tier
β-carotene supplements prevent cancer (even for smokers)
The evidence
CARET 1996 was halted early — β-carotene supplementation raised lung cancer in smokers. Antioxidant ≠ safe.
The mechanism, in brief
Vitamin A isn't one molecule — it's a group of compounds that convert to retinol.
Sources (1)
- National Institutes of Health, Office of Dietary Supplements. (2025). Vitamin A and Carotenoids — Fact Sheet for Health Professionals.