Mediterranean Diet Cuts Heart Attack, Stroke Risk

WASHINGTON—A diet rich in nuts, fruits and vegetables has been known to benefit the heart, and new research published in the journal Blood further demonstrates that the Mediterranean diet can decrease risk of heart attack and stroke.

The Mediterranean diet consists of fruits and vegetables, plenty of whole grains and nuts, and also fish and olive oil. New research has linked this eating plan to lower levels of platelets and white blood cells, two markers of inflammation that are also associated with a greater risk of heart attack and stroke. High platelet counts are linked to both vascular disease and non-vascular conditions such as cancer, and a high white blood cell count is a predictor of ischemic vascular disease.

To understand whether a diet rich in healthy compounds might favorably influence platelet and white blood cell levels, investigators in Italy conducted an analysis of the eating habits of nearly 15,000 healthy Italian men and women ages 35 years or older as part of the large epidemiological “Moli-sani" study, named for the inhabitants of the Molise region of Central and Southern Italy. Lead study author Marialaura Bonaccio, Ph.D., department of epidemiology and prevention at the IRCCS Istituto Neurologico Mediterraneo NEUROMED, said her team wanted to explain the Mediterranean diet's benefits in reducing long-term risk of chronic conditions.

All participants were evaluated at baseline and were considered to be healthy. Total platelet counts and white blood cell counts were measured and participants were grouped according to their levels (low, normal or high), based on age and gender-specific cut-offs. Participants with high platelet levels were younger and had a greater incidence of high cholesterol and increased levels of common inflammation marker C-reactive protein when compared to those in the normal or low platelet categories. Individuals in the high white blood cell category were mainly younger, male, and smokers, and they had a higher body-mass index and higher levels of C-reactive protein and blood glucose compared to those in the other groups. They also showed higher prevalence of high blood pressure and high cholesterol.

Study participants’ adherence to a Mediterranean diet was determined based on results of two dietary scoring systems, the Mediterranean diet score (MDS) or the Italian Mediterranean Index (IMI), which helped to accurately determine intake levels and portion sizes. Upon review of the data, investigators observed that consumption of the Mediterranean diet was directly related to lower levels of platelets and white blood cells, which in turn correlated to lower levels of inflammation. When compared to participants who did not follow the eating plan as closely, those who strictly followed a traditional Mediterranean diet were less likely to belong to study cohorts with relatively high platelet counts and were more likely to belong to cohorts with relatively low white blood cell counts.

“Because the study included healthy participants, the lower levels of platelets and white blood cells in those who were more strictly consuming a Mediterranean diet indicate that this eating plan could account for substantial changes within normal ranges of variability," Bonaccio said. "This is an important finding that has implications for how these anti-inflammatory markers are tracked among the general population."

The researchers also evaluated the role of specific components of the diet to help clarify the observed correlation, including food antioxidant content and fiber intake, both of which have previously been connected to cardiovascular benefits. These components only partially accounted for the link between the diet and white blood cell count, but did not fully explain the correlation to platelet levels.

“An important finding of this study is that it indicates that the Mediterranean diet as a whole, and not just a few specific ingredients, is likely responsible for the beneficial health outcomes among the healthy population and should be encouraged as part of healthy eating habits," Bonaccio added. “Building on these important findings, we continue to study this population to determine if the dietary habits may have an influence on cardiovascular disease-related mortality."