Written by Tim Williams, The Advertiser
TAKING folic acid supplements into the late stages of pregnancy could raise the risk in some children of developing allergies, Adelaide University research has found.
Folic acid is important before conception and in the first trimester to minimise risk of fetal defects and aid development of the central nervous system.
But animal testing suggests that continuing the supplement could reduce the natural protection from allergies that some babies have as a result of a common complication in about 10 per cent of pregnancies.
“Taking a folic acid supplement during the first trimester of pregnancy is important to reduce the risk of neural tube defects,” Dr Kathy Gatford, from the uni’s Robinson Research Institute, said.
“However, continued supplementation with folic acid into the later stage of pregnancy doesn’t reduce that risk, and there’s growing evidence that this may increase the risk of allergies in offspring.”
The neural tube develops into the brain and spinal cord. Australian guidelines recommend a daily supplement of folic acid, a type of vitamin B, at least one month before and three months after conception. Guidelines do not make recommendations beyond the first trimester.
Previous studies have shown that a pregnancy complication called intra-uterine growth restriction – growth restriction in the womb often resulting in low birthweight, and in the worst cases stillbirth – could have a protective affect against allergies such as asthma and food allergies. Various allergies affect up to 40 per cent of the population.
Dr Gatford’s research team has found that sheep born from growth-restricted pregnancies are less likely to be susceptible to developing allergies to egg white proteins — ascertained by injecting the allergen followed by skin prick tests — than those from normal pregnancies.
But when sheep with growth-restricted pregnancies were fed folic acid supplements late in pregnancy, their offspring lost that advantage.
“Studies in animal models like this allow us to directly investigate these effects of the environment before birth on later allergy,” Dr Gatford said.
“While the results help us to better understand the potential allergy risk in humans, more research is needed before any recommendations about the right timing of supplementation should or could be made in humans.”
The study will be published in the American Journal of Physiology.
Original article here.