Antioxidants, especially from the diet, may help prevent age-related cataracts, according to a new study published in the American Journal of Clinical Nutrition.

A cataract is a clouding up of the lens of the eye that eventually interferes with vision, and requires surgical removal for vision to be restored. Age, genetics, and the environment, as well as injury, trauma, and medications such as corticosteroids, are all factors that may contribute to cataract development, a common condition in people over age 65. Oxidative stress may also play a role, so the authors of this study investigated whether long-term use of antioxidants can help prevent cataracts.

The Blue Mountains Eye Study included 3,654 people over 48 years old. At the initial assessment, each participant had an eye exam and filled out a food frequency questionnaire, which noted antioxidant use including beta carotene, zinc, and vitamins A, C, and E. More than 66% of the people then attended a follow-up examination five and/or ten years later.

People who had the highest vitamin C intake from diet and supplements had a significantly reduced risk of cataracts after ten years compared with those who consumed less vitamin C. Those with above-average intakes of combined antioxidants, including vitamins C and E, beta carotene, and zinc, also had a reduced cataract risk compared with those who consumed fewer antioxidants.

The authors pointed out that the study participants overall ate lots of fruits and vegetables and had “fairly healthy diet habits.” Said Ava Grace Tan and her colleagues from the Department of Ophthalmology at the University of Sydney, Sydney, Australia, “Around one-third of the population was taking vitamin supplements at the baseline examination, with a median vitamin C intake of 500 mg among supplement consumers.”

Eating for eye health

The main dietary sources of vitamin C among people in the study were:

• Brassica vegetables, such as broccoli, spinach, and cabbage

• Potatoes

• Citrus fruits, such as oranges

• Fruit juice

Eating plenty of fruits and vegetables (five or more servings a day) in your daily diet is good for maintaining health and preventing a wide variety of diseases. Talk with your doctor about the right mix of dietary supplements for you based on your health.

Jane Hart, MD

(Am J Clin Nutr 2008;87:1899–905)