Folic Acid: what to do?

keaAs I’m a tiny bit busy moving house this week, I am going to feed two birds with one bun (a phrase which I believed was my own creation until I googled it just now out of curiosity and discovered that I actually wasn’t the first to think up this MUCH nicer version!*) and post up some more articles which will add to the collection here AND save me from having to send them all separately to the friend who asked me about this earlier in the week.

*(By the way please don’t feed keas buns or any other human food but just enjoy the picture, which was taken in one of my favourite NZ coffee shops :))

The folic acid decision seems fairly simple until you look at the research, whereupon you will discover  rather more complexities than you might have anticipated.  The articles that Tasha Cooper and I wrote on this topic come in a series of three – part one, part two, part three – and even after we had written that many pages, we still had a ton of unanswered questions.  Whether or not the potential risks of this supplement really outweigh its advantages for women who are just pregnant or planning to become pregnant is an individual decision (although depending on where you live, if you want to make the decision yourself rather than being state-medicated, you may wish to read food labels rather carefully!)  But concern is growing, and just this week I spotted another paper (the abstract of which I have shared below) which raises more questions about unanticipated side effects.  As the authors of this paper note, these concerns are only beginning to emerge and by no means negate the value of folic acid in preventing neural tube defects but, as is so often the case, many areas remain in need of further exploration.


This is one of Sara’s older articles and it is archived here for historical interest only. Click here to see her most recent posts and articles!


Folic acid supplementation in pregnancy: Are there devils in the detail?
Maternal folic acid (FA) supplementation is well recognised to protect against neural tube defects. Folate is a critical cofactor in one-carbon metabolism involved in the epigenetic regulation of transcription that underpins development. Thus, it is possible that maternal FA supplementation may have additional, unforeseen persistent effects in the offspring. This is supported by the modification by maternal supplementation with one-carbon donors and FA of the epigenetic regulation of offspring phenotype in mutant mice. The present article reviews studies in human subjects and experimental animals of the effect of maternal FA intake and phenotypic outcomes in the offspring. Maternal FA intake was associated with a short-term increased incidence of allergy-related respiratory impairment in children and multigenerational respiratory impairment in rats. Higher maternal folate status during pregnancy was associated positively with insulin resistance in 6-year-olds. In rats, maternal FA supplementation modified hepatic metabolism and vascular function through altered transcription, in some cases underpinned by epigenetic changes. FA supplementation in pregnant rats increased mammary tumorigenesis, but decreased colorectal cancer in the offspring. Maternal FA supplementation decreased a range of congenital cardiac defects in children. These findings support the view that maternal FA supplementation induces persistent changes in a number of phenotypic outcomes in the offspring. However, the number of studies is limited and insufficient to indicate a need to change current recommendations for FA intake in pregnancy. Nevertheless, such effects should be investigated thoroughly in order to support firm conclusions about the risk of unanticipated long-term negative effects of maternal FA supplementation in humans.
Burdge GC; Lillycrop KA (2012). Folic acid supplementation in pregnancy: Are there devils in the detail? British Journal of Nutrition 108(11):1924-1930