Question folic acid fortification.

Scientists at the U.K.'s Institute of Food Research (IFR) believe there may be consequences to fortifying flour with folic acid, based on new evidence of how it is absorbed by the body. In May, the U.K.'s Food Standards Agency's Board determined that mandatory fortification with folic acid should be introduced to reduce the number of babies born with neural tube defects. It would be compulsory to add folic acid to either bread or flour.

As you may know, folic acid is a synthetic form of folate, a B vitamin found in a wide variety of foods, including liver and green leafy vegetables. Folates are metabolized in the gut, whereas IFR scientists suggest that folic acid is metabolized in the liver. The liver is an easily saturated system, and fortification could cause unmetabolized folic acid to enter the blood stream, with the potential to cause a number of health problems.

With doses of half the amount being proposed for fortification, the liver becomes saturated, and unmetabolized folic acid floats around the blood stream. This can cause problems for people being treated for leukemia and arthritis, women being treated for ectopic pregnancies, men with a family history of bowel cancer and people with blocked arteries being treated with a stent. For women undergoing in-vitro fertilization, it can also increase the likelihood of conceiving multiple embryos, with all the associated risks. It could take 20 years for any potential harmful effects of unmetabolized folic acid to become apparent, we're told.

Unmetabolized folic acid accelerates cognitive decline in the elderly with low vitamin B12 status. But those with normal vitamin B12 status may be protected against cognitive impairment. Around 20% of those older than 65 in the United Kingdom have low B12 status. Since the 1980s, a consensus formed that folic acid is metabolized in the small intestine in a similar way to naturally occurring folates. This consensus was used to assess the safety of folic acid fortification. The IFR scientists challenge the underlying scientific premise behind this consensus: "Folic acid metabolism in human subjects revisited: potential implications for proposed mandatory folic acid fortification in the UK." British Journal of Nutrition (2007), October, 98.4.

Further information. Dr. Sian Astley, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, England, U.K.; phone: [phone]; fax: [phone]; email: [e-mail].