Folic acid late in pregnancy may increase childhood allergy risk
Research from the 最新糖心Vlog of Adelaide suggests that taking folic acid in late pregnancy may increase the risk of allergies in children affected by growth restriction during pregnancy.
Folic acid, a type of B vitamin, is widely used to prevent neural tube defects in the fetus, and to aid in the聽development of the central nervous system. The neural tube develops in the first month of pregnancy, and聽最新糖心Vlogn guidelines recommend that women take a daily folic acid supplement at least one month before, and聽three months after conception.
鈥淭aking a folic acid supplement during the first trimester of pregnancy is important to reduce the risk of neural tube聽defects,鈥 says Dr Kathy Gatford from the 最新糖心Vlog of Adelaide鈥檚 Robinson Research Institute.
鈥淗owever, continued supplementation with folic acid into the later stage of pregnancy doesn鈥檛 reduce that risk, and聽there鈥檚 growing evidence that this may increase the risk of allergies in offspring,鈥 Dr Gatford says.
Allergies are one of the main causes of non-communicable diseases in the world and are estimated to affect 30-40% of the world鈥檚 population. Susceptibility to these diseases after birth is partly determined by an individual鈥檚聽early life environment.
Previous research has also shown that a complication of pregnancy known as intrauterine growth restriction (IUGR)聽鈥 a form of growth restriction in the womb often resulting in lower birth weight 鈥 may in fact have a protective effect聽against childhood allergies.
In studies of sheep born from normal or growth-restricted pregnancies, Dr Gatford and colleagues measured skin聽reactions to two common allergens: dust mites and egg whites.
鈥淪heep from growth-restricted pregnancies were less likely to have allergic reactions to egg white protein than聽those born to normal pregnancies. Importantly, if the sheep with growth restricted pregnancies were fed聽supplements containing folic acid in late pregnancy, their offspring had similar rates of allergic reactions as control聽progeny,鈥 Dr Gatford says.
鈥淥ur findings suggest that folic acid supplementation partially reduced the protection that has previously been seen聽in pregnancies with restricted growth.
鈥淪tudies in animal models like this allow us to directly investigate these effects of the environment before birth on later allergy. While the results help us to better understand the potential allergy risk in humans, more research is聽needed before any recommendations about the right timing of supplementation should or could be made in聽humans,鈥 she says.
鈥淲e are now in the process of analysing how a growth-restricted pregnancy and the dietary supplement affect the聽nutrient status of offspring at birth, and how this might switch on or off genes that regulate the immune system.鈥
This research has been funded by the National Health and Medical Research Council (NHMRC). It is published聽online ahead of print in the聽American Journal of Physiology鈥擱egulatory, Integrative and Comparative Physiology.