A recent study questions the need for folic acid fortification.
A study from Ireland suggests that mandatory folic acid fortification may be unnecessary as many people may be getting plenty of folic acid already.
There are no implications of the findings for the general public at present, Dr. Mary Rose Sweeney of Dublin City University emphasized in an email to Reuters Health. However, she said the results should be taken into account by lawmakers considering mandatory fortification of some foods with the B vitamin.
Pregnant women who get enough folic acid reduce their risk of having a baby with spina bifida and other neural tube defects. For this reason, several countries, including the United States and Canada, now require grain products to be fortified with folic acid.
Many Irish food companies already fortify their products with folic acid, Sweeney and her colleagues note in the journal BMC Public Health, and Ireland's Food Safety Authority recommended in 2006 that fortification be made mandatory.
But safety concerns, including new evidence suggesting that a 1 mg daily dose of folic acid could speed the growth of colorectal and prostate cancers (more than twice the recommended dose for pregnant women), led the country to hold off on such legislation.
Sweeney and her team sought to determine how much folic acid people might already be getting in Ireland, and estimate how much this might increase if mandatory fortification went into effect.
They accomplished this by checking people's blood for folic acid that had not been processed by the body into its usable form. The presence of unmetabolized folic acid would suggest that people were getting adequate amounts of the nutrient.
In tests on 50 blood donors, the researchers found small amounts of unmetabolized folic acid in 49. And among 20 women who had just delivered babies by cesarean section, the researchers found unmetabolized folic acid in 18, and in the umbilical cords of 17 of their infants.
The findings raise the possibility that people, especially pregnant women, might be exposed to high levels of folic acid, which could accelerate tumor growth, Sweeney and her team suggest. They calculate that mandatory fortification of flour with folic acid could increase population levels of unmetabolized folic acid by 12%.
It will be necessary to conduct tests of unmetabolized folic acid levels in the general population after fasting to better understand the potential effects of mandatory fortification with the nutrient, Sweeney told Reuters Health.
"We do not know if there are safety implications from these low levels of unmetabolized folic acid but concerns that folic acid may accelerate existing cancers should continue to be of concern for those responsible for food policy legislation," she said.
"The challenge for public health agencies and legislators is to ensure that unborn babies are protected against neural tube defects while ensuring that the general population is not exposed to potentially harmful amounts of folic acid," Sweeney said.