Maintenance of Healthy Blood Glucose Levels during Pregnancy to Reduce the Risk of Gestational Diabetes Mellitus (GDM): Nutrition and Lifestyle Strategies

Nutrition and Health Research, Nestlé Research Center,
Lausanne, Switzerland
Irma.SilvaZolezzi@rdls.nestle.com

School of Chemistry and Molecular Biosciences,
and UQ Centre for Clinical Research, The University of Queensland
Brisbane, QLD, Australia

• The prevention of GDM is key to ensure optimal pregnancy outcomes for mother and infant.
• Supplementation with myoinositol and probiotics may proof to be a successful prevention strategy that can be easily adopted by women of childbearing age.

In pregnancy, insulin resistance and secretion increase to ensure an appropriate fetal nutrient supply; however, an excessive rise leads to gestational diabetes (GDM). Worldwide, the prevalence of GDM ranges between 6 and 13%, reaching 25% in some countries [1]. GDM is a multifactorial condition, but maternal overweight/obesity and excessive gestational weight gain (GWG) are important risk factors [2]. GDM is associated with adverse maternal outcomes, such as preeclampsia and future type 2 diabetes mellitus (T2DM), and short- and long-term morbidities in the infant including neonatal hypoglycemia, macrosomia, and future obesity and T2DM [2].

GDM treatment focuses on glycemic control through dietary changes with or without pharmacotherapy (metformin, glyburide, and/or insulin) [2]. However, given the adverse effects of GDM, preventive interventions are crucial. Different types of interventions have reported mixed results due to differences in diagnostic criteria, the use of nonstandardized interventions, and varying levels of adherence, particularly with lifestyle interventions [3].

Dietary modulation fails to reduce the incidence of GDM in lean women and has mixed effects in obese women [3], though a meta-analysis reported a 61% reduction of GDM risk [4]. Physical activity-based interventions in lean women also show conflicting results; and in obese women, they improve fasting glucose and insulin levels without reducing the rate of GDM [3]. Combined diet- and physical activity- based interventions do not reduce the incidence of GDM in lean or obese women, but they reduce GWG in obese women [3].

Specific nutritional interventions to prevent GDM have been tested. Supplementation with n–3 long-chain polyunsaturated fatty acids, which may enhance insulin action and improve glucose tolerance, does not consistently reduce the risk of GDM in a few small RCTs [3]. Furthermore, maternal vitamin D deficiency during early pregnancy increases the risk of GDM [5], but its supplementation does not reduce the incidence of GDM. However, most vitamin D studies do not including GDM as an outcome and have methodological flaws [6].

Two promising bioactive ingredients are myoinositol and probiotics (Fig. 1). Four small clinical trials in highrisk Italian women report that supplementation with myoinositol, an insulin- mimicker, reduces the risk of GDM by 60–70% and normalizes birth weight [7, 8]. Larger trials in other populations are warranted to confirm these results. The combination of two probiotic strains, Lactobacillus rhamnosus NCC4007 or LPR and Bifidobacterium lactis NCC2818 or BL818, reduced the risk of GDM by 61% in healthy Finnish women [8, 9], while also having beneficial effects on birth size, maternal adiposity, and blood glucose concentrations after delivery [10, 11]. Probiotics may act through balancing the gut microbiota, normalizing increased intestinal permeability, and/or controlling low-grade inflammation [12]. Additional insights will come from three on-going trials using the same probiotics mix [9].
 

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