Diet may prevent cataracts - Tufts University Human Nutrition Research Center on Aging

Nutrition Health Review, Spring, 1991 by Judy McBride

Diet May Prevent Cataracts

Worldwide, 50 million people suffer from clouded vision due to cataracts. In the United States alone, about 1.4 million people - mostly the elderly - underwent cataract surgery during the 1990 fiscal year. Medicare paid for 1.2 million of those surgeries at a staggering cost of nearly $3.2 billion. The cost in quality of life is even greater.

Mounting evidence suggests that many of these operations may be delayed or prevented if people consumed more fruits and vegetables and more of the antioxidant vitamins.

Researchers with The Human Nutrition Research Center on Aging at Tufts and the Brigham and Women's Hospital eye clinic recently took the most comprehensive look at the relationship between cataracts and diet in 112 people between the ages of 40 and 70. Seventy-seven of the participants had at least one cataract; 35 had clear lenses.

Both groups filled out a lengthy questionaire detailing how often they consumed various foods; they provided a history of their supplement use as well as blood samples. Although small in scale as epidemiology studies go, when the data were put through statistical analyses, significant differences appeared:

"Study subjects who had cataracts didn't eat as many fruits and vegetables," says Paul Jacques with the ARS/Tufts center's epidemiology program. Those who consumed less than 1.5 servings of fruit or fruit juice per day or less than two servings of vegetables or vegetable juice were three and a half times more likely to have cataracts. And those who fell short in both categories had a 5.7-times-higher incidence.

"These are arbitrary cutoffs," says Jacques. "Getting just two servings of vegetables a day probably isn't the optimum. But those subjects who fell below two servings appear to be at substantially increased risk."

The study also found a strong link between cataract incidence and antioxidants, particularly incidence and antioxidants, particularly vitamin C. Antioxidants are substances that help detoxify cell-damaging substances.

Participants whose vitamin C intake was in the lowest 20 percent - and that included people who reported getting more than the 60 milligram RDA - had 4 times the occurence of cataracts, says Jacques. A similar relationship emerged between vitamin C levels in their plasma and cataract incidence.

The statistics also showed, for the first time, a relationship between cataract occurrence and plasma levels of carotenoids - the red, yellow, and orange plant pigments, including beta carotene, says Jacques.

Cataracts were 5.6 times more prevalent among those with the lowest plasma levels. But they were not tied to the participant's intake of beta carotene, which accounts for only about 20 percent of the total carotenoids in the diet, he says.

Carotenoids are abundant in the dark-green leafy vegetables as well as the orange and red fruits and vetetables - tomatoes, peaches, squash, and, of course, carrots.