BACKGROUND: Smoking is believed to be a major risk factor for cataracts because it depletes antioxidant levels and increases free radical damage throughout the body. Several observational studies have found strong associations between high carotenoid intake from fruits and vegetables and a lower risk of eye diseases, including cataracts.
RESEARCH: In the Physicians' Health Study, researchers asked approximately 22,000 middle-aged and elderly male physicians to take a beta-carotene supplement (50 mg) or a placebo every other day for an average of 12 years.
RESULTS: When evaluating all subjects who completed the study, there was no effect of beta-carotene on risk of cataracts, nor was there any evidence of harmful effects. Further analyses revealed that smokers who took beta- carotene supplements had a 26 percent reduction in their risk of developing cataracts. Without beta-carotene supplementation, smokers had a 65 percent greater risk of developing cataracts compared to nonsmokers. Overall, there was a slight but non-significant trend toward lower risk of cataracts among nonsmokers.
IMPLICATIONS: This long-term study found that male smokers who took 50 mg of beta-carotene every other day had a lower risk of developing cataracts.
These results must be viewed with caution in light of previous studies that found possible adverse effects of beta-carotene in smokers.
Christen WG, Manson JE, Glynne RJ, et al, "A randomized trial of beta- carotene and age-related cataract in US physicians," Archives of Ophthalmology, 2003;120:372-378.
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