One study linked low blood levels of vitamin E to more rapid progression of cataracts in men with high cholesterol levels. A 1999 study found some weak benefits in people who ate foods high in vitamins C or E and who had other risk factors for cataracts. Other antioxidant supplements and food chemicals in the study did not seem to be protective with the exception of a carotenoid called lutein, which is found in dark green leafy vegetables. Riboflavin plays a critical role in the production of an important antioxidant enzyme called glutathione. In studies on animals, glutathione deficiency increase production of cataracts, and its administration, either intravenously, topically, or orally, cleared cataracts.
Some experts believe that reduction of glutathione is a key in the development of cataracts.
Substantial evidence exists, however, that taking beta-carotene supplements may increase the risk for lung cancer in smokers and may even have adverse effects on the heart. In any case, it is always wise to pursue a healthy diet that is low in fats, high in complex carbohydrates, and rich in fruits and vegetables. Dark green and yellow fruits and vegetables usually have high levels of beta-carotene and other important plant chemicals. Vitamin C is found in most fruits and vegetables, and vitamin E is found in avocados, kale, sweet potatoes, vegetable oils, and wheat germ. The best sources for riboflavin are dairy products, fortified grains, and meat.