Children of mothers who took folic acid supplements during pregnancy were at significantly lower risk of developing brain tumors during childhood, with the risk reduced by up to 45%, according to findings published in Cancer Epidemiology, Biomarkers & Prevention .
“A reduced risk of childhood brain tumors associated with maternal folic acid supplementation is biologically plausible through known mechanisms, and a stronger inverse association with use before pregnancy is consistent with the fact that ovarian stimulation and follicular development are subject to the availability of folate,” wrote researchers led by Elizabeth Milne from the Telethon Institute for Child Health Research at the University of Western Australia.
The study is observational and therefore shows correlation and not causation.
Folic acid intake before and during early pregnancy ensures that the fetus does not develop the neural tube defect – commonly known as spina bifida. Women of child-bearing age need sufficient body stores of folate before conception to prevent folate-sensitive neural tube defects (NTDs), which make up 20% to 60%of all NTDs.
Because of this, merely recommending folic acid supplementation before conception has been found to be an unsuitable strategy – mainly due to the fact that many pregnancies are unplanned, and the average time until the first antenatal visit is 9 weeks – meaning neural tube defects may have already occurred before this time.
As such mandatory fortification of staple foods with folic acid began in the USA in 1998; since then over 50 countries around the world have followed suit in adopting a fortification strategy.
Australia, where the new study was located, introduced a policy of folic acid fortification of all wheat flour for making bread in 2007 , with the policy enforced in 2009.
Milne and her co-workers identified 327 children with brain tumors at ten pediatric oncology centers and recruited 867 children free of brain tumors to act as controls.
Maternal supplement use was assessed by food frequency questionnaires.
Results showed that folic acid and multivitamin supplement use were associated with risk reductions of 32%.
“Our study of maternal folic acid supplementation and risk of childhood brain tumors is the largest and most comprehensive to date,” wrote the researchers.
“We conclude that folic acid supplements before and in early pregnancy may protect against childhood brain tumors. Potential underlying mechanisms should be further investigated, particularly for individual childhood brain tumors subtypes as the mechanisms may well differ.”
Source: Cancer Epidemiology, Biomarkers & Prevention
Published online ahead of print, doi: 10.1158/1055-9965.EPI-12-0803
“Maternal use of Folic Acid and Other Supplements and Risk of Childhood Brain Tumors”
Authors: E. Milne, K.R. Greenop, C.I. Bower, et al.