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Vitamin C protects against cataracts

BOSTON, MASSACHUSETTS. Cataract removal is the most commonly performed surgery among older people. It is estimated that about 45 per cent of all people over the age of 75 years have cataracts that impair their vision. Several studies have shown a protective effect of certain antioxidant vitamins specifically vitamin C, vitamin E and carotenoids. Researchers at Tufts University have just released the results of a large study designed to evaluate the effect of vitamins on the incidence of two specific types of cataracts, cortical cataracts and posterior subcapsular (PSC) cataracts. Because the two types occur in different part of the eye's lens the researchers reasoned that the vitamins required for protection might be different.

The study involved 492 non-diabetic women aged 53 to 73 years who were part of the large Nurses' Health Study begun in 1976. All participants had completed food frequency and supplement usage questionnaires every second year for 13 to 15 years. The researchers found lens opacities in 55 per cent of the participants with 37 per cent being cortical opacities and 6.3 per cent being PSC opacities. They also observed that women under the age of 60 years whose daily vitamin C intake exceeded 360 mg/day had a 57 per cent lower risk of developing a cortical cataract than did women whose intake was below 140 mg/day. Women under the age of 60 years who had supplemented with vitamin C for 10 years or more had a 60 per cent lower risk of cortical cataracts than did women who had not supplemented. Vitamin C did not appear to protect against the much less common PSC opacities, but carotenoids and, to a lesser extent, folic acid did seem to confer some protection amongst women who had never smoked. NOTE: The current Recommended Daily Allowance (RDA) for vitamin C is 75 mg/day for women – clearly totally inadequate for providing any meaningful protection against cataracts.
Taylor, Allen, et al. Long-term intake of vitamins and carotenoids and odds of early age-related cortical and posterior subcapsular lens opacities. American Journal of Clinical Nutrition, Vol. 75, March 2002, pp. 540-49

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