Introduction of the Mediterranean diet in pregnancy and the incidence of gestational diabetes mellitus: A systematic review of randomised controlled trials and meta-analysis.

ABSTRACT

OBJECTIVES: To determine if introducing the Mediterranean diet in pregnancy reduces the incidence of gestational diabetes. STUDY DESIGN: Systematic review and meta-analysis of randomised controlled trials (RCTs). A literature search was conducted using the following databases MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and CINAHL with no language or date restrictions. Studies were deemed eligible if the population was pregnant women, the intervention was the Mediterranean diet, and the outcome was gestational diabetes. Quality assessment was carried out using the Cochrane risk of bias tool. A random effects model using Revman software was used to pool results, generating a summary risk ratio with 95 % confidence intervals (95 %CI). RESULTS AND CONCLUSIONS: The search identified three eligible studies. Across the trials, 2348 women were included. Two of the three trials defined the intervention as the Mediterranean diet supplemented with extra virgin olive oil (EVOO) and pistachios, with the control group being Mediterranean diet alone. Meta-analysis of these trials found a significant reduction in the incidence of gestational diabetes in the intervention group compared to the control group (risk ratio=0.71, 95% confidence interval=(0.57, 0.88)). In addition, this was consistent with the results of the remaining eligible trial which defined the intervention as Mediterranean diet and the control as a standard UK diet (risk ratio = 0.71, 95% confidence interval = (0.55, 0.90)). At present evidence is scarce regarding whether adopting a Mediterranean diet reduces the risk of gestational diabetes. A large multi-centre randomised controlled trial is needed to definitively determine the impact of the Mediterranean diet in pregnancy on the incidence of gestational diabetes.