Fortification programmes may lead to overconsumption of folic acid
MOST people who seek to lead a healthy lifestyle know that they should eat an array of fruits and vegetables every day. But when good intentions go awry, or just as an insurance policy, there are always vitamin pills.
In particular, women hoping to become pregnant are advised in many countries to take double the recommended dose of folic acid. But because some people do not plan their pregnancies, several countries require that the grains used to make bread, breakfast cereals and suchlike be fortified with folic acid. It has worked. The Centres for Disease Control and Prevention, an American government agency, says that after fortification began, in 1998, the reported prevalence of spina bifida in babies declined by 31%. Research is also going on into whether high doses of the chemical prevent cardiovascular disease, strokes and cognitive decline. But can people consume too much folic acid?
The results of a study published in the Proceedings of the National Academy of Sciences suggest they can. Folic acid is a precursor of folate, a vitamin found in foods such as spinach and oranges. It is added to other foods because it was once thought to be the active vitamin. In fact, it is converted to folate in the liver by the addition of four hydrogen atoms.
However, Steven Bailey of the University of South Alabama and Bruce Ames of the University of California, Berkeley, warn that the liver has only a limited ability to make this conversion. This discovery is consistent with reports that unmetabolised folic acid is found in human blood and urine.
The good news is that the recommended daily dose of 0.4 mg is converted into folate in most people. The bad is that the amount put into cereals in America can lead people to consume up to 0.8 mg per standard serving. On top of this, pregnant women may be consuming a similar amount of folic acid from supplement pills.
The researchers warn that intakes of folic acid of more than 1mg a day, from whatever source, will increase the body’s exposure to circulating unmetabolised folic acid. This is not to be recommended, because high doses of folic acid are suspected of exacerbating certain cancers. That concern has led some countries, and the European Union collectively, to put programmes for grain fortification on hold. Dr Bailey and Dr Ames stress that folic-acid pills are good during pregnancy, and that aspiring mothers should not give them up. But for the rest the message is clear: eat your spinach.
Source of Information : The Economist August 29 2009