Feb. 23, 2009 — Taking a combination of B vitamins may offer a rare and inexpensive opportunity to help prevent the most common cause of blindness in older Americans, age-related macular degeneration (AMD).

A new study shows that women who took vitamins B6 and B12 along with folic acid had a 34% lower risk of any AMD and a 41% lower risk of AMD with significant vision loss.

Researchers say treatments for AMD are limited to people in the later stages of the disease.

“For the large population with early or no AMD, there is no method of disease prevention other than avoidance of cigarette smoking,” write researcher William Christen, ScD of Harvard Medical School and colleagues in the Archives of Internal Medicine. “From a public health perspective, this is particularly important because persons with early AMD are at increased risk of developing advanced AMD, the leading cause of severe, irreversible vision loss in older Americans.”

Vitamin Combo Curbs Macular Degeneration

In the study, researchers randomly assigned more than 5,000 women over 40 without signs of age-related macular degeneration to take a combination of 2.5 milligrams of folic acid, 50 milligrams of vitamin B6, and one milligram of vitamin B12 or a placebo every day. The women were part of a trial looking at the use of these vitamins and cardiovascular disease. The women had heart disease or at least three risk factors for heart disease at the start of the study.

During about seven years of follow-up, 137 new cases of age-related macular degeneration were diagnosed, including 70 that resulted in significant vision loss.

The results showed that women taking the B vitamin supplements had a 34% lower risk of any AMD and a 41% lower risk of AMD with vision loss than the placebo group.

Researchers say the benefits of the vitamin combination in preventing AMD appeared to emerge about two years after treatment began.

“The trial findings … are the strongest evidence to date in support of a possible beneficial effect of folic acid and B vitamin supplements in AMD prevention,” the researchers write. They note that further research is necessary in other groups of people to confirm their findings.