0941 Folate fortification – a good idea?

In 2007 the Food Standards Agency Board in the UK agreed on mandatory fortification of a staple food with folic acid but was asked to re-evaluate the recommendation because of public concerns about the potential for toxicity. This was not only of concern to Britons but also to others in Europe. On the other hand, folate fortification of flour and grain products has been mandatory in the USA, Canada and Chile for about a decade, and it now seems the UK is going in a similar direction with the country expecting an announcement from the Scientific Advisory Committee on Nutrition again recommending mandatory fortification. The rationale for this intervention is the prevention of congenital neural tube defects and possibly the prevention of other defects as well (cardiac and cleft lip and palate). While there is little doubt about a role for folate in preventing neural tube defects, there are questions about the mechanism of action. Incidence rates dropped by between 15 and 50% in the USA, Canada and Chile after fortification, but rates were falling even without fortification in these and other countries, so folate is likely only one piece of the puzzle. Critics of food fortification with folate question the wisdom of exposing whole populations to folate when the risk is only to pregnant women and their offspring. This introduces the issue of potential risks of overdosing and/or the deleterious effects of folate. On the one hand, folate deficiency has been associated with high plasma levels of homocysteine and consequent atherosclerosis and cardiovascular disease, and folate depletion is said to foster the development of cancer, particularly colorectal cancer. On the side of folate excess there are concerns that high levels promote progression of preneoplasms, this through the provision of nucleotide precursors to the preneoplastic cells. Folate is also an indirect methyl donor, with methylation possibly leading to inactivation of tumour suppressor genes and accelerated tumour progression. The conflicting data (e.g. colorectal cancer rate increases when folate down or up) perhaps support those who are calling for more studies before routinely adding folate to a staple food.

Read more:
Lancet 2009; 374: 959-60
Gut 2006; 55: 1387-9
Am J Clin Nutr 2008; 87: 517-33