BOSTON, MASSACHUSETTS. Cataracts are common among older people and it is estimated that more than one million surgical operations are performed in the United States every year to remove them. It is generally agreed that cataract formation involves oxidation of lens tissue and that dietary antioxidants may prevent or delay this oxidation. Researchers at the Harvard Medical School now report that the carotenoids lutein and zeaxanthin may be particularly effective in preventing cataracts. Their studies involved almost 80,000 females nurses and over 35,000 male health professionals who were enrolled in 1980 and 1986 respectively. The female study group completed diet questionnaires in 1980 and 1984 and were then followed up until 1992 at which time 1471 cataract extractions had been performed. The male group completed diet questionnaires in 1986 and were followed up until 1994 at which time 840 cataract extractions had been performed.
The researchers found that nurses with a high intake of lutein and
zeaxanthin had a 22 per cent lower risk of cataract extraction
than did women with the lowest intake. Among the men, the 20 per
cent with the highest intake had a 19 per cent lower risk when
compared with the 20 per cent with the lowest intake. The
researchers found a significant protective effect of spinach, kale
and broccoli, but found no significant effects of other
carotenoids and could not confirm a previously reported protective
effect of vitamin A. They conclude that lutein and zeaxanthin may
reduce the risk of cataract formation and recommend daily
consumption of fruits and vegetables high in carotenoids.