Folic acid supplementation and childhood asthma

A team of Australian researchers has identified a relationship between allergic asthma in children 3-5 years of age and exposure to folic acid taking their mothers in the form of supplements in late pregnancy. The invetigadores warn that the time of pregnancy who take these supplements can be very important and should be taken into account when recommending them.

This study has been conducted under the direction of Dr. Michael Davies, Associate Professor, Research Center for the Origins of Health and Disease, Institute Robins of the University of Adelaide (Australia) and has published online the November 15, 2012 in the American Journal of Epidemiology.

In many countries (for Spain) public health recommendations often advise pregnant women to supplement their diet with 400 micrograms of folic acid per day, at least from the month before conception and during the first trimester of pregnancy, to reduce the risk of neural tube defects of the baby, which can become very serious (anencephaly, spina bifida).

However, the commonly accepted idea that folic acid supplements can only provide benefits have been questioned in recent studies with mice and children, showing that the intake of folic acid supplements during pregnancy has adverse health effects baby's breathing. Thus, a recent comprehensive study conducted in Norway 32 077 children indicated that folic acid supplementation during pregnancy is associated with breathing difficulties and infections of the lower respiratory tract (see ha · berg SE, London SJ, Stigum H, et al. Folic acid supplements in pregnancy and early childhood respiratory health. Arch Dis Child. 2012, 94 (3) :180-184.)

Dr. Michael Davies has said that his study supports the official recommendations for the prevention of neural tube defects, because they saw no increased risk of asthma when folic acid supplements were taken only before pregnancy or during the first quarter. "Our findings show that there is a critical period, which can be very important, during which the dose of folic acid supplements can be adjusted to optimize neuroprotective effect without increasing the risk of asthma."

"In our study, we found that folic acid supplementation during late pregnancy were associated with an increased risk of childhood asthma, but there was no evidence for unexpected side effects if taken in early pregnancy," added Davies.

The authors conclude: "These findings on childhood asthma are consistent with previous observations that folic acid supplementation during pregnancy leads to a phenotype of allergic asthma in mice by epigenetic mechanisms, which is associated with worse respiratory outcomes in young children. "

The authors say their study may help understand why childhood asthma is increasing in developed countries in recent decades.

"The official recommendations for folic acid should enlarge to include the warning to avoid the use of high dose folic acid supplements in the last months of pregnancy," added Davies.

He stressed that they found no evidence that asthma had no relation to the folate found naturally in foods like green leafy vegetables and some fruits and nuts.