Beta-Carotene
Beta-carotene is a provitamin A carotenoid converted to retinol in the body. Despite observational data showing dietary beta-carotene inversely associated with cancer risk, large RCTs found no cancer prevention benefit. CRITICALLY, the ATBC trial (n=29,133 smokers) showed 18% increased lung cancer risk with 20mg/day, and CARET (n=18,314 high-risk) showed 28% increased lung cancer incidence with 30mg/day—both trials were stopped early. The Physicians' Health Study (n=22,071) found no benefit for cancer or CVD over 12 years. Meta-analysis: 24% increased lung cancer risk in smokers with high-dose supplements. HIGH-DOSE SUPPLEMENTATION CONTRAINDICATED IN SMOKERS. Dietary sources (fruits/vegetables) remain protective.
Quick Answer
What it is
Beta-carotene is a provitamin A carotenoid converted to retinol in the body. Despite observational data showing dietary beta-carotene inversely associated with cancer risk, large RCTs found no cancer prevention benefit.
Key findings
- Grade D: Non-Melanoma Skin Cancer Risk (Skin Cancer)
- Grade D: Overall Cancer Risk (General Cancer Care and Prevention)
- Grade D: CVD Mortality (Cardiovascular Disease)
Safety
- Despite observational data showing dietary beta-carotene inversely associated with cancer risk, large RCTs found no cancer prevention benefit.
- CRITICALLY, the ATBC trial (n=29,133 smokers) showed 18% increased lung cancer risk with 20mg/day, and CARET (n=18,314 high-risk) showed 28% increased lung cancer incidence with 30mg/day—both trials were stopped early.
- Meta-analysis: 24% increased lung cancer risk in smokers with high-dose supplements.
ℹ️ Quick Facts: Beta-Carotene
Quick Facts: Beta-Carotene
- Best Evidence:Grade D
- Conditions Studied:4
- Research Outcomes:5
- Key Effect:Lung Cancer
Detailed Outcomes
Evidence by Condition
Best grade per condition (each condition may have multiple outcomes)
Research Citations (8)
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