Vitamin B intake linked with lower risk of macular degeneration 

Risk of developing age-related macular degeneration (AMD) is reduced in women taking a combination of B vitamins and folic acid, suggests research published in the Archives of Internal Medicine (2009;169:335).  

The randomised, double-blind trial involved 5,442 women aged 40 years and older with pre-existing heart disease or at least three risk factors. Of these, 5,205 did not have AMD at the beginning of the study and were assigned to take placebo or a combination of folic acid (2.5mg per day), pyridoxine hydrochloride (vitamin B6, 50mg per day) and cyanocobalamin (vitamin B12, 1mg per day).  

After an average of 7.3 years of treatment and follow-up, 137 new cases of AMD were documented. Of these, 55 cases occurred in the active treatment group (2,607 women) and 82 cases occurred in the placebo group (2,598 women). The researchers calculate that women taking the supplements had a 34 per cent lower risk of any AMD and a 41 per cent 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 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.  

As well as lowering homocysteine levels, potential mechanisms for the effectiveness of B vitamins and folic acid in preventing AMD include antioxidant effects and improved function of blood vessels in the eye, the researchers suggest.