Cataract: Nutritional Considerations

Epidemiologic studies have shown associations between several nutritional factors and cataract risk. These factors have not been tested in controlled intervention trials, however. The principal factors under study are described below.

Maintaining serum lipids within established norms. Researchers have identified relationships between elevated levels of triglycerides, chylomicrons, and VLDL and increased cataract risk.^9,10 There appears to be an inverse association between HDL concentrations and cataract risk.^9,11

Reducing total fat intake and avoiding certain kinds of fat. Compared with those eating the least (25% of calories) fat, those eating the highest amount (37%) had a 10% greater risk for cataract.^12,13 Type of fat may also influence cataract risk. Women consuming the highest percentage of energy from polyunsaturated fat (6% of calories from linoleic acid and ~0.7% calories from alpha-linolenic acid) had a 12% greater risk for cataract than persons consuming the least (~4. % and ~0.5%, respectively).^12,13 Eating fish > 3 times per week was associated with a 12% lower risk for cataract extraction compared with women eating the least fish.¹²

Avoiding dairy products. Persons with heterozygous galactokinase deficiency¹⁴ and elderly persons who have diminished activity of this enzyme are at greater risk for cataract.¹⁵ Dairy products, which contribute the majority of the galactose to the diet, should be avoided in these patients.

Eating more fruits and vegetables. Since antioxidant-rich diets have been associated with a lower risk of cataract, incorporation of more vegetables and fruits may prevent or slow the progression of cataract.

Consuming more carotenoid-containing vegetables. The consumption of dark, leafy green vegetables, such as spinach, broccoli, kale, collards, mustard greens, and turnip greens, has been associated with a reduced risk of cataract. These vegetables are rich sources of the antioxidant carotenoid lutein,¹⁶ which, along with the closely related zeaxanthin, is present in the crystalline lens.¹⁷

Emphasizing antioxidant-rich foods. Some evidence suggests that high doses of antioxidants help prevent cataract formation¹⁸ and that the antioxidant vitamins C and E may retard the progression of cataract. Good sources of vitamin C include citrus fruits, peppers, tropical fruits, cantaloupe, strawberries, kiwifruits, cruciferous vegetables, tomatoes, potatoes, and sweet potatoes. Good sources of vitamin E include wheat germ, cooked spinach, soy milk, many varieties of nuts, sunflower seeds, mangos, and olive, peanut, and vegetable oils.

Avoidance of alcohol can help prevent the more common type of cataract. Compared to non-drinkers, individuals who consumed more than 2 glasses per week of any type of alcohol (beer, wine or distilled spirits) had a 13 percent higher risk for nuclear opacity.¹⁹

Orders

See Basic Diet Orders chapter.

In cases of galactokinase deficiency, avoid dairy products.

Control of plasma lipid concentrations (see Hyperlipidemia chapter ).

Limit sun exposure.

Smoking cessation.

Alcohol restriction.

What to Tell the Family

It is important for the patient and family to understand that cataract is not a cancer and that harm rarely occurs to the remainder of the eye structure. The decision as to when to have surgery depends upon the patient's perceived degree of disability. When surgery is necessary the chance for restoration of vision is excellent.

Supplements of lutein or other antioxidants should not take the place of a diet rich in dark, leafy green vegetables. The possible benefit associated with vegetables may be partially due to the presence of other phytochemicals that have not yet been fully identified. Since family members of cataract patients are also at risk for cataract, their adoption of a similar healthful diet is advantageous. The family can also help the patient avoid tobacco, and excessive sunlight and alcohol exposure. These diet and lifestyle changes offer many other health benefits as well.