BOSTON, MASSACHUSETTS. Researchers at Tufts University and the Harvard Medical School have confirmed that a high intake of antioxidants (from diet or supplements) helps prevent the development of cataracts (age-related nuclear lens opacities). Their recent study included 478 female nurses who had completed food frequency questionnaires every second year since 1980. The questionnaires included details of vitamin and mineral supplement use. During the period 1993 to 1994 the study participants all underwent a detailed eye examination and had blood samples taken for analysis of plasma concentrations of vitamin C and vitamin E and the carotenoids.
The researchers conclude that vitamins C and E, riboflavin (vitamin B), folic acid, beta-carotene, and
lutein/zeaxanthin all protect against cataract development. However, after adjustment for other nutrients
only the association with vitamin C remained statistically significant. Women whose daily vitamin C intake
(from diet and supplements) was between 140 and 180 mg/day had a 48 per cent lower risk of cataracts
than did women whose intake was below 140 mg/day. Women with an intake between 240 and 360 mg/day
had a 66 per cent lower risk than did women with an intake of less than 140 mg/day. Intakes above 360
mg/day did not lower the risk beyond the reduction obtained at intakes between 240 and 360 mg/day. This
finding is consistent with prior observations that human eye tissues become saturated with vitamin C at
intakes between 200 mg and 300 mg/day. The new findings make it glaringly obvious that the officially
recommended daily vitamin C intake for women of 75 mg/day (RDA) is inadequate to provide any
meaningful protection against cataracts. The researchers also found that women who had used vitamin C
supplements for 10 years or longer had a 64 per cent reduced risk of cataracts while those having
supplemented with multivitamins had a 43 per cent lower risk.