Scientists at the Institute of Food Research have highlighted possible consequences of fortifying flour with folic acid due to new evidence of how it is absorbed by the body.
In May, the Food Standards Agency’s Board agreed unanimously that 'mandatory fortification' with folic acid should be introduced to make sure the number of babies born with neural tube defects is reduced. This means that it would be compulsory to add folic acid to either bread or flour.
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 metabolised in the gut, whereas in a paper to be published in the British Journal of Nutrition in October IFR scientists suggest that folic acid is metabolised in the liver. The liver is an easily saturated system, and fortification could lead to significant unmetabolised folic acid entering the blood stream, with the potential to cause a number of health problems.
“Fortifying UK flour with folic acid would reduce the incidence of neural tube defects”, said Dr Siân Astley of the Institute of Food Research. “However, with doses of half the amount being proposed for fortification in the UK, the liver becomes saturated and unmetabolised folic acid floats around the blood stream.
“This can cause problems for people being treated for leukaemia and arthritis, women being treated for ectopic pregnancies, men with a family history of bowel cancer, people with blocked arteries being treated with a stent and elderly people with poor vitamin B status. For women undergoing in-vitro fertilisation, it can also increase the likelihood of conceiving multiple embryos, with all the associated risks for the mother and babies.
“It could take 20 years for any potential harmful effects of unmetabolised folic acid to become apparent”.