Taking vitamin E supplements, as well as a higher intake of the B vitamins riboflavin and thiamine, could slow cataract progession, suggest US researchers.
Age-related cataract, the world's leading cause of blindness, affects more than 20 million Americans over the age of 40 years.
Surgical correction is currently the only known option for intervention, but researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University are investigating whether dietary changes can help prevent cataracts.
In a study published in the April issue of the Archives of Ophthalmology (123, pp517-526), the scientists found that women who reported supplementing their diets with vitamin E for 10 years or more had significantly less progression of cataract development after five years of follow-up.
A similar relative decrease in cataract progression was seen in women who reported higher intakes of two of the B vitamins, riboflavin and thiamin, when compared to women with lower intakes.
"Our results suggest that vitamin supplementation, particularly long-term use of vitamin E, may slow down cataract development," said lead scientist Paul Jacques.
These results build upon some of Jacques' earlier work. In 2001, while examining the same group of Nurses' Health Study members, Jacques and his colleagues found support for a similar role for vitamin C in the prevention of cataracts.
But when it comes to fatty acids, the relationship with cataracts is not so clear.
In the same population of women, Jacques and his colleagues found that high dietary intake of either or both an omega-6 polyunsaturated fatty acid (PUFA) found in sunflower, safflower, corn, and soybean oils, and an omega-3 PUFA found in canola, flaxseed, and soybean oils, may increase the risk of developing cataracts in one of the three lens locations examined.
But the results of this study, published in the April issue of the American Journal of Clinical Nutrition (81, pp773-779), are not consistent, with findings from previous research.
Writing in the May issue of the American Journal of Epidemiology, Jacques and colleagues observed that higher overall fat intake increased the risk of cataract development or progression, while omega-3 fatty acids, in particular the types found in dark-fleshed fish, appeared to contribute to the prevention of cataract formation.
More research is needed to clear up this confusion but the researchers have added to the evidence showing a relationship between diet and cataracts.