Pregnant women eating a Mediterranean-style diet including a daily portion of tree nuts (half being walnuts) and extra virgin olive oil, had a 35 percent lower risk of gestational diabetes and gained 2.75 pounds less, compared to women who received standard prenatal care.
A Mediterranean-style diet rich in good, unsaturated fats, found in foods like walnuts and extra virgin olive oil, 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 ALA content (2.5g/oz - the only nut significantly high in this essential fatty acid) 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, making this study particularly valuable.
Conducted by researchers at Queen Mary University of London and the University of Warwick, this 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 UK national recommendations for prenatal care and weight management during pregnancy.
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 it's important to note that 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.
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. These findings provide additional support for following a Mediterranean-style diet which has been linked to additional health benefits such as improved cognitive function.