Folic Acid Does Not Raise Risk of Cancer

Diets rich in leafy green vegetables, citrus fruits and whole grains generally provide plenty of folic acid, a B vitamin that is essential for cell growth and the health of blood and nervous system tissues. Foods such as cereal and bread are fortified with folic acid in the U.S. to ensure that pregnant women get enough of this crucial nutrient to prevent neural tube birth defects in their babies.
Scientists have been concerned, however, that larger amounts of folate in the diet might help cancer cells grow and increase the risk of colorectal tumors. Results of a study started in 1995 before folate supplementation have eased anxiety about that hazard.
More than half a million adults have been included in the study. Their dietary habits and health were tracked for more than a decade. The people getting the most folic acid were 30 percent less likely to develop colorectal cancer than those who consumed very small amounts of the vitamin. The researchers acknowledge that this association does not show that folic acid is responsible, but it does help allay the fear that folic acid supplements would boost cancer risk. Dietary sources of folic acid include beans and other vegetables as well as greens and fortified grains.

[American Journal of Clinical Nutrition, online Aug.3, 2011]