Study disputes beta carotene’s value to vision

CHICAGO – Carrots, rich in beta carotene, long have been thought to sharpen eyesight, but a new study suggests that beta carotene pills are powerless against a common type of vision loss among older people.

Age-related macular degeneration is the leading cause of blindness in people 65 and older. The condition blurs the center of the field of vision, making it difficult to read, drive, thread a needle and even recognize faces. It affects more than 10 million Americans and there is no cure.

An earlier large study had shown that beta carotene – when taken with certain vitamins and zinc – could slow or prevent vision loss in people with age-related macular degeneration. Commercial formulations of the eye-protecting combination vitamins are sold over the counter.

But the new study found no benefit for beta carotene supplements alone against the disease.

The finding is based on data from more than 21,000 male doctors who were followed for an average of 12 years. The doctors were randomly assigned to take either 50 milligrams of beta carotene every other day or a dummy pill. The doctors didn’t know whether the pills they took contained beta carotene.

Roughly the same number of doctors in both groups developed the eye condition, suggesting beta carotene didn’t help or hurt. After 12 years, there were 162 cases of macular disease in the beta carotene group and 170 cases in the group taking the dummy pills.