B Vitamins Fail to Lower Heart Risks
Daily Folic Acid, B Vitamins Do Not Reduce Heart Disease, Stroke in High-Risk Women
May 6, 2008 -- Folic acid and B vitamin
supplements continue to prove that they can significantly lower blood
levels of homocysteine, a major risk factor for cardiovascular disease, but
when it comes to actually reducing
heart disease and
stroke, the combo appears to have no impact.
A study of more than 5,000 women at high risk for cardiovascular disease
showed that daily folic acid (vitamin B-9) and vitamin B-6 and B-12
supplementation did not reduce the rate of cardiovascular events, despite
lowering levels of the amino acid homocysteine. High levels of the amino acid
have been linked to a higher risk of heart disease, stroke, and fatty deposits
in the arteries.
The results, published in the May 7 issue of The Journal of the American
Medical Association, uphold findings from previous studies.
For the study, Christine M. Albert, MD, MPH, of Brigham and Women's Hospital
and Harvard Medical School, and colleagues randomly assigned female health
professionals to either a placebo or a combination pill containing 2.5
milligrams of folic acid, 50 milligrams of vitamin B-6, and 1 milligram of
vitamin B-12. The women were 42 years old or older with a history of
cardiovascular disease or three or more heart disease risk factors.
Researchers followed the women for about seven years. Blood tests performed
in a small subset of the women showed that women who received the supplements
had an average 18.5% lower level of homocysteine than those who took the
However, the lower homocysteine level did not appear to sway the number of
cardiovascular events. During the seven-year follow-up, 796 women had some type
of cardiovascular event, including a
heart attack, stroke, or death due to cardiovascular disease. Some women
had more than one event.
There was no significant difference in the number of events between the two
groups. Cardiovascular events occurred among 14.9% of those who received the
folic acid/vitamin B supplements and in 14.3% of those who received the fake
Researchers say the risk of death from any cause was also similar between
the two groups.
"Our results are consistent with prior randomized trials performed
primarily among men with established vascular disease and do not support the
use of folic acid and B vitamin supplements as preventive interventions for
[cardiovascular disease] in these high-risk fortified populations," the
Folic Acid, B Vitamins Not Recommended for Heart
The American Heart Association does not recommend widespread use of folic
acid and B vitamin supplements to reduce the risk of cardiovascular
Because homocysteine levels were measured in only a small number of women,
this study was not able to evaluate whether women with high homocysteine levels
may have benefited to a greater extent.
In an accompanying editorial, Eva Lonn, MD, MSc, FRCPC, of McMaster
University in Hamilton, Ontario, says folic acid and B vitamin supplements
cannot be recommended for preventing heart disease and strokes, except in the
case of rare genetic disorders.
"However, ongoing clinical research should provide further evidence on
whether there may be any role for homocysteine-lowering B vitamin supplements
in [cardiovascular disease] prevention and for the overall importance of
homocysteine as a cardiovascular risk factor," she writes.