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 (2.5 g/oz) 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 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 U.K. national recommendations for prenatal care and weight management during pregnancy.
Those who followed the Mediterranean diet consumed a daily portion of nuts (30 g/day; 15 g walnuts, 7.5 g almonds, 7.5 g hazelnuts) and used extra virgin olive oil (0.5 L/week) 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.
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. According to study authors, these findings provide additional support for following a Mediterranean-style diet which has been linked to additional health benefits such as improved cognitive function.