Dec. 11, 2000 -- Eat your carrots for good eyesight. Moms have been preaching it for years. Although carrots don't have all of the vitamins proving to do the eyes good, researchers are finding that mom was at least on the right track.
Vitamins C, E, and other antioxidants may reduce the risk of cataracts among people who get a lot of the vitamins for 10 or more years, according to a new study that adds to a growing body of research on the subject.
But researchers are quick to caution that it is too early to tell which specific vitamins protect against cataracts and other age-related eye diseases. A cataract is a clouding of the eye's lens that causes loss of vision and commonly happens as people age. Sixty percent of all adults over age 60 experience poor vision due to cataracts.
"Several studies have found that the long-term use of supplements of various types are related to lower occurrences of common age-related eye diseases, suggesting that diet may play a role," says lead author Julie A. Mares-Perlman, PhD, an associate professor in the department of ophthalmology and visual sciences at the University of Wisconsin in Madison.
"It's still important to get the nutrients you need from food and rather than taking a single nutrient, and it's better to take a multivitamin," she tells WebMD. Mares-Perlman and her colleagues' findings appear in the November issue of the journal Archives of Ophthalmology.
Researchers tracked the development of cataracts during a five-year period among more than 3,000 people aged 43 to 86. Risk of cataracts was 60% lower among people who took multivitamins or any supplement containing vitamin C or E for more than 10 years. However, using supplements for shorter amounts of time were not associated with reduced risk.
But those people who reported taking supplements containing vitamin C or E were also more likely to report engaging in other healthy habits such as regular exercise, the study shows. Such unmeasured lifestyle differences between supplement users and nonusers may help explain the findings, the researchers write.
Exactly how vitamins might prevent cataracts is not fully understood. One theory is that free radicals -- natural but damaging substances formed in the body during daily activities -- may make the eye more susceptible to disease including cataracts. But antioxidant vitamins, like vitamins C and E, may help protect healthy cells from free radical damage.
Colette Heimowitz, MS, director of education and research at the Atkins Center in New York, tells WebMD that she has had great success using antioxidants to prevent the disease.
"Antioxidants are of particular importance for the prevention of cataracts," she says. "Antioxidants can help if a person already has cataract formation by slowing the progress, but if it is more advanced or if there is already clouding of the lens, stronger dosages of certain nutrients are recommended."
Also important, Heimowitz stresses, is blood sugar control for diabetics since uncontrolled blood sugar can result in cataracts.
"The eyes are susceptible to free radical damage and protecting them from ... damage with antioxidants as well as avoiding the overuse of sugar is a good way to help protect against cataract," agrees Michael Janson, author of Dr. Janson's New Vitamin Revolution and a doctor in private in Arlington, Mass.
One of the foremost researchers on nutrients and eye disease, Allen Taylor, PhD, says that the most consistent positive results have been seen with higher blood levels of vitamin C. When it comes to lowering cataract risk with antioxidants, "the jury is still out on almost all antioxidants except for C," he tells WebMD. Taylor is director of the laboratory for nutrition and vision research at the U.S. Department of Agriculture's Human Nutrition Research Center on Aging at Tufts University in Boston.
Until more research can be done, "I tend to think that a prudent, good diet rich in fruits and vegetables and some kind of multivitamin would not a bad idea," Taylor adds.