Toward an optimal use of folic acid: an advisory report of the Health Council of the Netherlands.

In this report, benefits (preventing neural tube defects and folate deficiency), risks (masking vitamin B(12) deficiency), and uncertain effects (risk of colon cancer) of folic acid supplementation and fortification have been weighted. On the basis of the available evidence, the Health Council of the Netherlands advises the Dutch government to improve the use of folic acid approximately at the time of conception by increased education and the implementation of preconception care. It further recommends considering fortifying staple foods, provided that voluntary fortification of specific foods is banned, as otherwise children are at risk of having an excessively high intake of folic acid. Policy making in relation to fortification should take into account all possible health effects, even if the evidence is not strong.