Vitamin supplements help prevent age related macular degeneration

macular degenerationArch Intern Med 2009;169:335-41 [PubMed Abstract]

Age related macular degeneration is a leading cause of visual impairment in developed countries. A new study suggests that supplements combining folic acid and vitamins B6 and B12 may help prevent it.

In a placebo controlled trial of women with a high risk of cardiovascular disease, the supplements reduced the risk of new early eye disease by 34% (55/2607 v 82/2598; adjusted relative risk 0.66, 95% CI 0.47 to 0.93). Participants took the vitamins or a placebo for an average of 7.3 years. Benefits appeared after two to three years and persisted to the end of the trial.

Folic acid and the B vitamins reduce serum concentrations of homocysteine, an amino acid that has been linked to both cardiovascular disease and age related macular degeneration. Although supplements to lower homocysteine concentrations have consistently failed to prevent cardiovascular disease, they do seem to have an effect on macular degeneration, say the authors. Perhaps homocysteine is more damaging to the small vessels of the choroid than the large vessels of the heart.

The study of macular degeneration was embedded in a larger trial of various vitamin supplements for the prevention of cardiovascular disease in high risk women. The encouraging findings for macular degeneration need to be confirmed in dedicated trials, and in other populations, say the authors.

© 2009 BMJ Publishing Group Ltd.