A new study published in the journal Nutrients has raised questions about the unintended effects of folic acid fortification in Australia, linking it to a sharp increase in gestational diabetes cases.
Researchers compared data from two large groups of pregnant women (2,464 participants in total) recruited before and after the country mandated folic acid fortification in 2009.
This “natural experiment” showed that rates of gestational diabetes mellitus (GDM) tripled after fortification, while maternal folate stores rose by 259%.
The study also found that key placental hormones involved in glucose regulation, including human placental lactogen (hPL) and placental growth hormone (GH2), were altered in ways that may affect blood sugar metabolism.
Blood samples collected in early pregnancy were analysed for serum folate (short-term intake) and red cell folate (long-term stores) to provide a clearer picture of maternal folate status.
Importantly, the same diagnostic criteria for GDM were applied across both groups, ensuring a valid comparison. Researchers say the findings point to widespread maternal folate excess as a potential contributor to Australia’s gestational diabetes epidemic.
While folic acid fortification is widely credited with reducing neural tube defects, the authors caution that its long-term metabolic effects warrant further investigation.
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