Folate advice not good enough?

Posted on Tue, 30 Oct 18

Most women in the United Kingdom are not consuming enough folate to reduce risk of birth defects. Taking into consideration poor dietary exposure and wide-spread deficiency, current recommendations for folate supplementation may be too low. 

A recent analysis of nutrient intakes in reproductive age women found that 96% had intake of iron and folate below daily recommendations for pregnancy [1]. Adequate intake of folate is critical for improving pregnancy outcomes with estimates suggesting a substantial number of neural tube defects could be prevented with improved folate intake [2]. 

Because diet is relatively ineffective at achieving adequate folate concentrations in pregnancy for the prevention of neural tube defects (red blood cell folate concentration above 906 nmol/L) supplementation is recommended [3]. 

Current recommendations for pregnancy are folate or a folate-containing multivitamin supplement providing 400 µg/ day [4], however a recent study suggests this amount may not be able to achieve optimal red blood cell (RBC) folate levels to prevent birth defects [5].

Because the daily folate dose needed to achieve RBC-folate levels is not well established, a research group set out to test the difference between 400 or 800 µg/day of folate over 8-weeks in Germany which, like United Kingdom, does not have mandatory folic acid fortification and low dietary intake as a consequence. 

At baseline, 88% of women had RBC-folate levels below 906 nmol/L. Remarkably, women with low RBC-folate levels were unlikely to achieve optimal levels with 400 µg/day. Compared to the 400 µg/ day dose it was found that significantly more women taking 800 µg/ day achieved optimal RBC-folate concentrations at 4 weeks (31.3 vs. 45.5% for 400 µg and 800µg, respectively) or 8 weeks (54.5 vs. 83.8%).

“In a country without folic acid fortification, the current recommendation to supplement 400 µg/day is not sufficient to achieve protective RBC-folate levels if supplemented for 4–8 weeks,” commented the study investigators.

The supplement used in this study was a 50:50 mixture of folic acid and calcium-L-methylfolate (L-5-MTHF), which may have improved folate status compared to folic acid alone.

References: 

1. Stephenson J, Heslehurst N, Hall J, et al. Before the beginning: nutrition and lifestyle in the preconception period and its importance for future health. Lancet. 2018 May 5;391(10132):1830-1841.

2. Morris JK, Rankin J, Draper ES, et al. Prevention of neural tube defects in the UK: a missed opportunity. Arch Dis Child. 2016 Jul;101(7):604-7.
3. Cuskelly GJ, McNulty H, Scott JM. Effect of increasing dietary folate on red-cell folate: implications for prevention of neural tube defects. Lancet. 1996 Mar 9;347(9002):657-9.
4. Scientific Advisory Committee on Nutrition. Folic acid updated recommendations. 12 July 2017. 
5. Obeid R, Schön C, Wilhelm M, Pietrzik K, Pilz S. The effectiveness of daily supplementation with 400 or 800 µg/day folate in reaching protective red blood folate concentrations in non-pregnant women: a randomized trial. Eur J Nutr. 2018 Aug;57(5):1771-1780.