Mediterranean diet during pregnancy associated with improved health

Women who followed a Mediterranean-style diet during pregnancy, including a daily portion of tree nuts and extra virgin olive oil, had a 35 percent lower risk of gestational diabetes and on average gained 2.75 pounds less compared to women who received standard prenatal care, according to a new study published in PLOS Medicine.

Conducted by researchers at Queen Mary University of London in England and the University of Warwick in Coventry, England, the new study included 1,252 multi-ethnic, inner-city pregnant women with metabolic risk factors, including obesity and chronic hypertension. In addition to receiving folic acid and vitamin D supplementation, the women were randomly assigned to either a Mediterranean-style diet or a control group that received dietary advice per national recommendations for prenatal care and weight management during pregnancy.

Those who followed the Mediterranean diet consumed a daily portion of nuts including walnuts, almonds, and hazelnuts, and used extra virgin olive oil as their main source of cooking fat. In addition, the diet emphasized fruit, vegetables, non-refined grains, and legumes, moderate to high consumption of fish, small to moderate intake of poultry and dairy products, low intake of red meat and processed meat, and avoidance of sugary drinks, fast food, and food rich in animal-based fat.

Participants received dietary advice at 18, 20, and 28 weeks' gestation to help improve compliance and make sure the diet was made culturally sensitive. Investigators measured dietary compliance using self-reported feedback from the participants, so researchers note there could have been human error in the reporting.

The investigators also assessed the effect of a Mediterranean diet on other pregnancy complications such as high blood pressure, preeclampsia, stillbirth, small for gestational age fetus, or admission to a neonatal care unit, but did not find any significant associations, according to the study abstract.

A Mediterranean-style diet has been shown to reduce the risk of heart attack, stroke, and cardiovascular death in adults, according to the landmark PREDIMED study. Walnuts, in particular, are a traditional food in the Mediterranean diet because of their omega-3 content and bioactive compounds. While there has been extensive research on the Mediterranean diet to date, the diet's potential to improve maternal and offspring outcomes has not been widely evaluated.

One in four mothers enter pregnancy with pre-existing obesity, chronic hypertension or raised lipid levels, which can lead to pregnancy complications, long-term risk of diabetes and cardiovascular complications for mothers and their children. Researchers say these findings provide additional support for following a Mediterranean-style diet, which has been linked to additional health benefits such as improved cognitive function.