Foods Rich in Vitamin C May Reduce Cataract Risk

En español | Your risk of developing cataracts — a clouding of the eye’s lens that impairs vision— starts to climb at age 40. But a new study finds that a diet high in vitamin C–rich foods may cut that risk by a third.

Don’t try to take a shortcut by popping a vitamin C tablet: Supplements don’t have the same effect, British researchers found. Only foods naturally high in the antioxidant vitamin, including citrus fruits and dark green vegetables, seem to protect against cataracts.

“While we cannot totally avoid developing cataracts, we may be able to delay their onset and keep them from worsening significantly by eating a diet rich in vitamin C,” study lead author Christopher Hammond, M.D., a professor of ophthalmology at King’s College London, said in a statement. 

The study was published in March in the journal Ophthalmology.

The research also showed that diet may play a more important role than genetics when it comes to cataracts. Genetic factors accounted for 35 percent of the risk of cataracts worsening, while environmental factors, including diet, accounted for 65 percent, researchers reported.

In the study, scientists followed the progression of cataracts in 324 pairs of 60-year-old female twins from the United Kingdom over 10 years. The women’s intake of vitamin C was measured using a food questionnaire. Those who ate more vitamin C–rich foods had a 33 percent lower risk of cataracts and clearer lenses after 10 years, compared with those who consumed less vitamin C.

Why is vitamin C so important? The fluid in the eye that bathes the lens is high in vitamin C, which helps stop the lens from oxidizing and protects it from becoming cloudy, researchers explained. The belief is that increased intake of vitamin C helps protect cataracts from progressing by increasing the amount of the vitamin in the eye fluid.

Keep in mind, this study only found an association between vitamin C–rich diets and cataracts; it did not prove cause and effect.

Still, as Hammond noted, it suggests that “simple dietary changes, such as increased intake of fruits and vegetables, could help protect [older adults] from cataracts.”

According to the U.S. National Eye Institute, more than 24 million Americans had cataracts in 2010, the latest data available; that is estimated to rise to 40 million by 2030. White Americans and women have the highest risk. By age 80, the government estimates 70 percent of white Americans will have cataracts, compared with 53 percent of African Americans and 61 percent of Hispanics.

To add vitamin C–rich foods to your diet, think beyond oranges. The government-recommended daily amount of vitamin C is 60 milligrams (mg). An orange has about 70 mg. Here are some other foods with high C levels, according to the U.S. Department of Agriculture:

• Red bell pepper, ½ cup: 95 mg.
• Orange juice, ¾ cup: 93 mg.
• Kiwifruit, 1 medium: 64 mg.
• Green bell pepper, ½ cup: 60 mg.
• Strawberries, fresh, ½ cup: 49 mg.
• Broccoli, cooked, ½ cup: 51 mg.
• Kale, raw, ½ cup: 40 mg.
• Broccoli, raw, ½ cup: 39 mg.
• Cantaloupe, ½ cup: 29 mg.