Nutritional supplementation for the prevention and/or treatment of gestational diabetes mellitus

Purpose of Review: Gestational diabetes mellitus (GDM) is a common pregnancy complication that has short- and long-term health implications for both the mother and child. While lifestyle modifications, insulin therapy, and oral agents such as metformin are effective, they can be difficult to adhere to, and there remain concerns over long-term effects of oral agents on the infant. Further, GDM has no proven preventive strategies, which could be more effective than treatment postdiagnosis. Nutritional supplements are an appealing, potentially safer, and better tolerated alternative to pharmaceuticals to treat and/or prevent GDM. Here, we review the existing evidence for nutritional supplementation for treatment and prevention of GDM. Recent Findings: There is limited evidence that myo-inositol, vitamins D and B6, magnesium, selenium, zinc, fatty acids, and probiotics might be beneficial for the prevention or treatment of GDM. There are very few studies for each nutrient, and the existing studies tend to have few participants. Where multiple studies of a nutrient exist, often those studies were conducted within the same country, limiting the generalizability of the findings, or alternatively there was no consensus across findings. Summary: There is limited evidence that nutritional supplementation of myo-inositol, vitamins D and B6, magnesium, selenium, zinc, fatty acids, and probiotics could improve glycemic control or prevent GDM. Our understanding is constrained by the small number of studies, small sample sizes in most studies, and by lack of consistency across findings. Further large, high-quality, randomized controlled trials are required to determine the efficacy of nutritional supplements to treat or prevent GDM.