U.K. researchers warn against folic acid fortification

U.K. researchers are warning against mandatory folic acid fortification in flour, after the British Food Standards Agency agreed earlier this year that the fortification should be introduced to reduce the number of babies born with neural tube defects.

The U.K. Institute of Food Research issued a Statement of Concern in October detailing the difference between folic acid, a synthetic version of the B vitamin folate, and the natural form, which is found in a variety of foods, including leafy green vegetables. According to a paper in the October British Journal of Nutrition, folates are metabolized in the gut, while folic acid is metabolized in the liver. The paper contends that because the liver is an easily saturated system, fortification could lead to significant amounts of unmetabolized folic acid entering the bloodstream, potentially causing a number of health problems.

Excess folic acid could be problematic for people being treated for leukemia and arthritis, as well as men and women with other health issues, said Dr. Sian Astley of the IFR, in a statement. Folic acid supplementation has also been linked to increased incidences of breast cancer in postmenopausal women and bowel cancer. "Fortifying U.K. flour with folic acid would reduce the number of neural tube defects. However, with doses half the amount being proposed for fortification, the liver becomes saturated and unmetabolized folic acid floats around in the bloodstream." Astley added that it could take 20 years for any potentially harmful effects of unmetabolized folic acid to become apparent.

Since 1996, the U.S. has required folic acid fortification in certain enriched grain products, relying on scientific consensus that folic acid is metabolized in the small intestine similarly to natural folate. The IFR study challenges that consensus, Astley said.

The new findings could affect the possible legislation in the United Kingdom, as the Food Standards Agency board is preparing its recommendation to health ministers regarding fortification.