Pharmacy Daily | Concern as excess folic acid linked with gestational diabetes

SOUTH Australian researchers have raised concerns about over-supplementation of folic acid (FA) during pregnancy, after linking excess levels of the nutrient with a rise in gestational diabetes mellitus (GDM).

National surveillance shows the incidence of GDM in Australia has more than tripled, rising from 5.6% in 2010 to 19.3% in 2022.

That period saw the government-mandated FA fortification of flour, as well as a growing number of vitamin supplements containing 800g or more of FA, up from the 400g recommended in clinical guidelines for pregnancy.

This means now almost all women exceed the 1000g daily limit of FA.

The team from Adelaide University and Flinders University proposed that increased FA/folate supply from the mother to the placenta can alter placental function (hormone secretion), placing women at increased risk of GDM - a finding that has been seen in animals.

The researchers took into account known GDM risk factors, such as maternal obesity, age and ethnicity, as well as a change in diagnostic criteria that resulted in a small increase in GDM incidence.

The study comes just after a meta-analysis linked GDM with risk of autism and ADHD (PD 15 Sep).

"Our study suggests that higher-than-recommended FA intake may have unintended consequences for pregnancy," said study co-lead Dr Jankovic-Karasoulos from Flinders University.

"The placenta is central to regulating maternal glucose tolerance in pregnancy, so we need to understand how high FA intake affects placental function and, in turn, insulin resistance and gestational diabetes risk."

The findings highlight an urgent need to establish a safe upper limit for folic acid intake during pregnancy and to improve guidelines on folic acid supplementation during pregnancy, the team concluded.

Read the study HERE.