Folic acid effects two-faced depending on B12 levels, says study

The effects of increased folic acid intake amongst the elderly may be a double-edged sword, with benefits and harm dependent on the person’s vitamin B12 levels, says a new study.

“In this study of older Americans in the age of folic acid fortification, we found direct associations between high serum folate and both anaemia and cognitive impairment in subjects with low vitamin B12 status,” wrote lead author Martha Morris from Tufts University's Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging.

“Among subjects with normal vitamin B12 status, on the other hand, high serum folate was associated with protection from cognitive impairment.”

The results, published in the current issue of the American Journal of Clinical Nutrition, have important implications for mandatory folic acid fortification worldwide.

Maternal consumption of folate, or its synthetic form folic acid, is strongly associated with a reduced risk of neural tube defect (NTD) in the early states of pregnancy. Fortification of certain food groups with folic acid has been mandatory in North America since 1998, and the number of pregnancies affected by NTDs is reported to have fallen by 26 per cent.

To date no European country has followed suit, although the wheels are in motion in Ireland and it now looks increasingly likely that the UK will introduce measures in 2007.

Folic acid fortification has been on the table in the UK since 2000, following a report by the Scientific Advisory Committee on Nutrition's (SACN) predecessor COMA, which concluded that universal fortification of flour with folic acid would significantly reduce the number of conceptions and births complicated by NTDs.

But after consultation with stakeholders the decision was taken not to make fortification mandatory at that time due to concern that it may mask vitamin B12 deficiency in some sectors of the population and because it would impinge on consumer choice. 

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