Tuesday, February 24, 2009

B6, B12, and Folic Acid Reduce Risk of Macular Degeneration

A combination of vitamins B6, B12 and folic acid appears to decrease the risk of age-related macular degeneration in women. This news comes to us via the February 23 issue of Archives of Internal Medicine.

Age-related macular degeneration (AMD) is a leading cause of vision loss in older Americans. Treatment options exist for those with severe cases of the disease, but the only known prevention method is to avoid smoking. Much of the recent science on AMD has shown a connection to high blood levels of homocysteine, an amino acid. High levels of homocysteine are associated with dysfunction of the blood vessel lining. This current work shows that treatment with vitamin B6, vitamin B12 and folic acid appears to reduce homocysteine levels -- as a result, it may even reverse this blood vessel dysfunction.

William G. Christen, Sc.D., of Brigham and Women’s Hospital and Harvard Medical School, 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 AMD 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 AMD through November 2005.

Women taking the supplements had a 34 percent lower risk of any AMD and a 41 percent lower risk of visually significant AMD. “The beneficial effect of treatment began to emerge at approximately two years of follow-up and persisted throughout the trial,” the authors write. The trial findings reported are the strongest evidence to date in support of a possible beneficial effect of folic acid and B vitamin supplements in AMD prevention.


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