Folic acid & breast cancer

Taking large doses of folic acid may slightly increase a woman's risk of breast cancer, says study.

A new study conducted by Scotland's University of Aberdeen suggests that taking folic acid is associated with breast cancer risk.

The findings suggest that taking very large doses of folic acid during pregnancy may slightly increase a woman's risk of dying from breast cancer decades later.

The study led by researcher Marion Hall included some 3,000 women who had taken part in a trial of folic acid supplementation during pregnancy in the 1960s. At the time, the women took either 0.2 or 5 mg of folic acid a day or a placebo throughout their pregnancies.

The women in the 1960s trial taking the largest dose of folic acid took more than 10 times that amount. A review of medical records in 2002 revealed that 210 of the women had died since participating in the trial almost four decades earlier. Forty of the deaths were related to heart disease, 112 women died of cancer, and 31 of those deaths were from breast cancer.

The death rate among women taking folic acid was slightly higher than that among women who did not take the vitamin, but no difference was seen in the incidence of cardiovascular deaths. The risk of death from breast cancer in women taking the largest dose of the vitamin was twice that of the women taking a placebo in the study.