Walnuts are a traditional component of the Mediterranean diet and a key ingredient in the landmark PREDIMED study.
A Mediterranean diet including nuts, primarily walnuts, reduced the risk of cardiovascular diseases by 30% and specifically reduced the risk of stroke by 49% when compared to a reference diet consisting of advice on a low-fat diet (American Heart Association guidelines). The Mediterranean diet enriched with extra-virgin olive oil also reduced the risk of cardiovascular diseases by 30%. The Mediterranean diets had favorable effects on body mass index, blood pressure, insulin resistance, blood lipids, lipid oxidation, and systemic inflammation. Please note, because the study participants lived in Spain, were over the age of 55 and were at high cardiovascular risk; whether the results can be generalized to persons at lower risk or to other settings requires further research.