Mediterranean Diet Linked to Improved Gestational Diabetes Outcomes, Study

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By : Suvarna Sheth

Women with gestational diabetes who were on a Mediterranean diet for 3 months had improved glycemic levels, that were comparable to pregnant women with normal glucose levels, a new study from Madrid, Spain suggests.

The objective of the study was to assess whether Mediterranean diet-based medical nutrition therapy facilitates near-normoglycemia in women with gestational diabetes.

“Medical nutrition therapy based on a MedDiet enhanced with extra virgin olive oil and pistachios, thus with a high-fat content, is associated with glycemic control and with a reduction in gestational diabetes-related adverse perinatal outcomes,” Dr. Alfonso Calle-Pascual, one of the study authors told dLife.

When asked what specifically about a MedDiet is believed to help glycemic levels, Calle-Pascual says extra virgin olive oil is a rich source of monounsaturated fatty acids and has been found to lower postprandial glucose levels, as well as to improve the inflammatory profile.

“Extra virgin olive oil could have limited weight gain by reducing the carbohydrate load of meals,” he explains, “Furthermore, its liberal use facilitates an increased intake of vegetables, traditionally eaten with olive oil in Spanish cuisine.”

Calle-Pascual says pistachios are rich in unsaturated fatty acids, fiber, magnesium, and other phytochemical constituents with potential beneficial effects on insulin sensitivity, fasting glucose levels, and inflammation.

He says pistachios facilitate weight loss within energy-restricted diets. “It seems to be possibly due to enhanced satiety, increased thermogenesis, incomplete mastication, and fat malabsorption,” he adds.

How was the Study Designed?

The study was a secondary analysis of the St. Carlos GDM Prevention Study and was conducted between January and December 2015 in Hospital Clínico San Carlos in Madrid, Spain.

One thousand consecutive women with normoglycemia were included before 12 gestational weeks, with 874 included in the final analysis.

Of these participants, 177 women were diagnosed with gestational diabetes and 697 had normal glucose tolerance.

All women with gestational diabetes received Mediterranean diet-nutrition therapy, which focused on whole grains, fruits, vegetables, and good fats. They were also given a recommended daily extra virgin olive oil intake ≥40 mL and a daily handful of nuts.

The primary goal was to compare hemoglobin A1c (HbA1c) levels at 36–38 gestational weeks in women with gestational diabetes as well as in women with normal glucose tolerance.

What Were the Findings?

Results of women with gestational diabetes had higher HbA1c levels at 24–28 gestational weeks.

At 36–38 gestational weeks, values were similar between both groups of women.

Similarly, fasting serum insulin and homeostatic model assessment insulin resistance was higher in women with gestational diabetes at 24–28 weeks but became similar at 36–38 weeks.

Within the study, 26.6 percent of women with gestational diabetes required insulin for glycemic control.

Women with gestational diabetes compared with normoglycemia subjects had higher rates of insufficient weight gain, small for gestational age, and neonatal intensive care unit admission.

“Our data indicate the potential benefit of using this type of diet as medical nutrition therapy in women with gestational diabetes,” Calle-Pascual says. “We would, therefore, recommend the adoption of this nutritional intervention by pregnant women, from the start of gestation.”

He says important implications for the long-term health of the mother and their infant may be expected. The health impacts on the future risk of disease in both women and their offspring are currently being investigated in an ongoing study.


  1. Assaf-Balut C, et al. BMJ Open Diabetes Res Care. Medical nutrition therapy for gestational diabetes mellitus based on Mediterranean Diet principles: a subanalysis of the St. Carlos GDM Prevention Study 2018. Retrieved: