Electronic Food Rap
Vol. 6 No. 8
Bill Evers, PhD, RD and April Mason, PhD
Extension Foods and Nutrition Specialists
Looking for "cause and effect" answers from chemicals in our food has always been a ripe ground for misinformation. The following on beta-carotene points out, again, that simple solutions to difficult problems are rarely the best solutions.
(Submitted by Lisa Spence, Extension graduate assistant)
Source: An ALERT to IFT Food Science Communicators via email, 1/18/96
Beta-carotene & Vitamin A in Cancer Prevention
The ability of beta-carotene and vitamin A to prevent lung cancer in smokers and other high risk groups of adults may not be as strong as once postulated. The National Cancer Institute has funded research in this area through the Alpha-Tocopherol, Beta- Carotene Cancer Prevention Trial (ATBC); the Beta-Carotene and Retinol Efficacy Trial (CARET); and the Physicians' Health Study (PHS).
ATBC studied male smokers for 5-8 years in which subjects took alpha tocopherol, beta carotene, both, or a placebo daily. Results indicated that 18% more lung cancers and 8% more overall deaths occurred in subjects taking beta carotene. CARET researched the effect of beta carotene/vitamin A supplements on men and women smokers, former smokers, and men exposed to asbestos to evaluate the supplements' efficacy on lung and other cancer prevention. After 4 years of supplementation, 28% more lung cancers and 17% more deaths occurred in those on beta carotene and vitamin A than those taking placebos. Neither the ATBC nor the CARET proved benefits from supplementation. CARET was stopped early on 1-11-96 by investigators due to a possibility of harm to participants from supplements. The PHS tested the ability of beta carotene supplements to reduce cancer risk and heart disease in male physicians during a 12 year period. No benefit or harm was shown in subjects taking supplements.
NCI has never recommended supplements to Americans. The best advice to smokers is to stop smoking. The results from the ATBC and the CARET suggest that smokers avoid beta carotene supplements. However, the 5-A-DAY program (eating 5 fruits and vegetables daily) is still advised. To reduce the risk of cancer, NCI recommends adoption of a low-fat diet containing plenty of fruits, vegetables, and grains.
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