MONDAY, Oct. 11 (HealthDay News) -- Despite reducing levels of a protein associated with heart disease, supplements containing the B vitamin folic acid don't reduce the risk for cardiovascular disease, death or cancer, according to a new large-scale analysis of studies on the issue.
Folic acid helps prevent devastating neural tube birth defects such as spina bifida. Since it also lowers blood levels of the protein homocysteine, which is linked with heart and blood vessel disease and other ills, some scientists hoped that the powerful vitamin might lower the risk of heart disease, stroke or cancer.
The current meta-analysis suggests that even taken at high doses, folic acid supplements don't have that effect.
The report is published in the Oct. 11 issue of the Archives of Internal Medicine.
"Vitamins are necessary to prevent diseases of deficiency like scurvy and rickets, but more is not necessarily better and may be harmful," said Dr. Jeffrey A. Tice, assistant professor of medicine in residence at the University of California, San Francisco and author of an accompanying journal editorial.
To examine folic acid supplements' possible role in preventing cancer, heart disease or stroke, a team led by Robert Clarke, from the University of Oxford in England, collected data on 37,485 people who took part in eight trials comparing the value of folic acid supplements against placebo. These trials represented all the large randomized studies available that were designed to lower plasma homocysteine levels for the prevention of cardiovascular disease.
Over five years, there were 9,326 major coronary events, including strokes and new heart procedures. In addition, 3,010 patients developed cancer and 5,125 people died, according to the report.
Even though those taking folic acid saw a 25 percent reduction in homocysteine levels, they were just as likel
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