Cataracts - Prevention

Vitamins and Food

Antioxidant vitamins C and E. Because of the role oxidants may play in cataract formation, researchers are investigating the benefits of antioxidant vitamins and other food chemicals. Vitamins C, E, and riboflavin (a B vitamin), for example, are helpful in preserving glutathione levels, an enzyme that helps protect against oxidation in the eye. Low levels of vitamin C in the lens of the eye have been particularly strong predictors of cataracts. There is also some evidence that ultraviolet B radiation interacts with deficiencies in certain antioxidants, such as vitamin E and zinc, to increase damage in the corneas and lenses of the eye.

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Evidence on the benefits of supplements of vitamin E or C, or vitamin-rich foods, is conflicting. For example, in two identically constructed trials in the US and Britain, the American group derived apparent benefits from vitamins E, C, and beta carotene while the British group reported very little cataract protection. A 2005 study suggested that long-term use of vitamin E supplements may slow cataract development. However, in a major on-going American study called the Age-Related Eye Disease Study (AREDS), researchers reported no difference in the incidence of cataracts after 7 years in people who took the antioxidant vitamins compared to those who took sham vitamins.

High doses of vitamins may have harmful effects. It is always wise, in any case, to pursue a healthy diet that is low in fats, high in complex carbohydrates, and rich in fruits and vegetables.

B vitamins. Some studies report some protection from a number of B vitamins, including vitamins B1 (thiamin) B2 (riboflavin), B3 (niacin) and B12 (folate). Riboflavin, for example, plays a critical role in the production of glutathione, an enzyme that helps protect against oxidation in the eye. All forms of vitamin B are widely available in dairy products, fortified grains, and meat.

Carotenoids. Carotenoids are a group of more than 700 fat soluble nutrients that produce the colors in foods such as carrots, pumpkins, sweet potatoes, tomatoes, and other deep green, yellow, orange, and red fruits and vegetables. Many are proving to be very important for health. Different carotenoids may be more beneficial then others. They include:

Xanthophylls are compounds that form a particular category of carotenoids. The xanthophylls lutein and zeaxanthin are found in the lenses of the eye and may be of significant importance for people at risk for cataracts. Some evidence indicates supplements of xanthophyll-rich foods may help retard the aging process in the eye and protect against cataracts. In fact, some experts suggest that the higher risk of cataracts in women compared to men may be partly due to a lesser ability to transport these carotenoids from the blood into the eye. Xanthophylls can be obtained from dark green leafy vegetables (such as spinach), broccoli, and eggs.
Lycopene is an important carotenoid that may also play an important role in eye health as a person ages. Tomatoes are the importance sources of lycopene.
Beta carotene is the most widely studied carotenoid and is a powerful antioxidant. It has been specifically studied for cataract protection. Most studies, however, have found little or no benefits. A 2003 study did suggest that beta carotene may protect against cataracts in smokers, although it is important to note that other studies report a higher risk for lung cancer in smokers who take beta carotene.

Click the icon to see an image of folate sources.

Click the icon to see an image of vitamin B12 sources.

Click the icon to see an image of riboflavin sources.

Phytochemicals. Phytochemicals are substances in plants that have beneficial effects. Dark colored (green, red, purple, and yellow) fruits and vegetables usually have high levels of important plant chemicals and have been associated with a lower risk for cataracts. Tea contains certain plant chemicals called polyphenols that have been associated with protection against cataracts.