Vitamins to prevent macular degeneration
Age-related macular degeneration (AMD) is the leading cause of severe irreversible vision loss in older Americans.
Researchers from Harvard Medical School in Boston examined the combined effect of folic acid, pyridoxine hydrochloride (vitamin B6), and cyanocobalamin (vitamin B12) on the risk of AMD.
First, the details.
- 5442 adult female healthcare professionals with preexisting cardiovascular disease or at least 3 cardiovascular disease risk factors participated in the study.
- They were randomly assigned to a treatment for about 7 years.
- Folic acid 2.5 mg/day; B6, 50 mg/day; and B12, 1 mg/day
- Placebo
- Neither the researchers nor patients knew the treatment given — double-blind.
And, the results.
- There were 55 cases of AMD with combination treatment vs 82 in the placebo group — a significant difference.
- For visually significant AMD, there were 26 cases with combination treatment vs 44 in the placebo group — a significant difference.
The bottom line?
The authors concluded that in women at high risk of cardiovascular disease, daily supplementation with folic acid, pyridoxine, and cyanocobalamin may reduce the risk of AMD.
This is the first study of its kind (randomized, double-blind) to investigate supplemental use of folic acid and B vitamins in the prevention of AMD. The authors tell us that the beneficial effect of treatment became apparent at about 2 years of treatment and persisted throughout the study.
The mechanism driving the beneficial effect in these women might be related to lower homocysteine blood levels caused by the vitamins. More research will have to sort this out.
2/24/09 10:37 JR