February 24, 2009

B vitamins reduce macular degeneration

Taking a combination of vitamins B6 and B12 and folic acid appears to decrease the risk of age-related macular degeneration in women, U.S. researchers said.

William G. Christen of Brigham and Women's Hospital and Harvard Medical School in Boston and colleagues conducted a randomized, double-blind clinical trial involving 5,442 women age 40 and older who already had heart disease or at least three risk factors.

Of these, 5,205 did not have age-related macular degeneration at the beginning of the study. In April 1998, these women were randomly assigned to take a placebo or a combination of folic acid -- 2.5 milligrams per day, pyridoxine hydrochloride -- vitamin B6, 50 milligrams per day and cyanocobalamin -- vitamin B12, 1 milligram per day. Participants continued the therapy through July 2005 and were tracked for the development of age-related macular degeneration through November 2005.

Over an average of 7.3 years of treatment and follow-up, 137 new cases of age-related macular degeneration were documented, including 70 cases that were visually significant -- resulting in a visual acuity of 20/30 or worse.

Women taking the supplements had a 34 percent lower risk of any age-related macular degeneration and a 41 percent lower risk of visually significant age-related macular degeneration.

The beneficial effect of treatment began to emerge at approximately two years of follow-up and persisted throughout the trial, the study authors said in a statement.