The mandatory fortification of staple foods with folic acid: a current controversy in Germany.

INTRODUCTION: The mandatory fortification of staple foods with folic acid to prevent neural tube defects (NTDs) began in the USA in 1998. Since then, more than 50 countries around the world have followed suit.
METHODS: Selective literature review including national study results. RESULTS AND DISCUSSION: Women of child-bearing age need sufficient body stores of folate before conception to prevent folate-sensitive NTDs, which make up 20% to 60% of all NTDs. Merely recommending folic acid supplementation before conception has been found to be an unsuitable strategy. Ingestion of folate-fortified food markedly increases folate intake, generally by about 50% of the recommended daily total intake. In Germany at present, debate surrounds the issue whether folate intake should be raised by mandatory folate supplementation, which will affect the entire population. Folate deficiency is associated with a higher risk of cancer and other diseases; on the other hand, there is concern that very high folic acid intake might promote the growth of pre-neoplastic lesions. There are no consistent study findings to support the latter hypothesis¸ and the evidence for it is derived from research in animals whose folate metabolism differs from that in humans. About 800 pregnancies with NTD are diagnosed each year in Germany; in most cases, the pregnancy is terminated after positive prenatal screening. The incidence of NTDs in Germany is estimated at 12.36 per 10 000 births (a mean figure derived from registry data in Mainz and Saxony-Anhalt) and is thus much higher than the mean incidence across Europe, 7.88 per 10 000 births (EUROCAT data for 2004-2008). Mandatory folic acid fortification should be adopted, as it is a highly effective and inexpensive way to prevent NTDs.