LONDON, Dec 10 (AFP) - Folic acid, a B vitamin widely taken by pregnant women to protect against birth defects, has been linked to an increased risk of breast cancer, in a British health study published Friday.
But the researchers said their results could merely be the result of chance, as other studies have suggested that folic acid actually reduces the risk of breast cancer, and they urged pregnant women to continue taking the supplement.
Folic acid, found naturally in dark, leafy vegetables, is known to be a key aid in the growth of the fetus.
Researchers from the universities of Bristol and Aberdeen followed 3,000 women who in the 1960s were given supplements of either five milligrams or 0.2 milligrams of folate, or a placebo, mostly during the second and third trimesters of pregnancy.
By September 2002, breast cancer rates were twice as high for those who took the five-milligram supplement as for those who took the placebo, according to the study published in the British Medical Journal.
Andy Ness, one of the researchers, stressed the results were merely "preliminary findings... intended to point the way towards further research."
"It is entirely possible that this is a chance finding, so further scientific studies are required to examine the association, if there is one, before we reach any conclusions," he said.
Ness said women planning to become pregnant should still take folic acid supplements, saying there was a "considerable difference between the trial" and current dosage recommendations.
Women hoping to become pregnant and those in the first trimester of their pregnancy should, according to British health guidelines, take a 0.4-microgram daily supplement of folic acid -- more than 10 times smaller than the doses given to women in the study.
12/10/2004 01:08 GMT - AFP