Mediterranean Diet May Help Prevent Stroke in Genetically At-Risk Individuals

A Mediterranean diet may help prevent stroke in individuals whose genetics put them at greater risk of experiencing one.

The reason lies in the diet's interaction with a gene variant associated with the development of type 2 diabetes but whose relationship to cardiovascular disease risk has been uncertain to researchers for years.

Of the 7,000 individuals included in the new study, roughly 14 percent carried two copies of the gene and, as such, had an increase risk of disease.

Each participant was assigned to either a Mediterranean or low fat control diet and monitored for cardiovascular disease, stroke and heart attack over the course of almost five years. At the end of the trial period, the researchers found that those with two copies of the variant that strictly adhered to a Mediterranean diet saw a reduction in strokes.

"The food they ate appeared to eliminate any increased stroke susceptibility, putting put them on an even playing field with people with one or no copies of the variant," explained senior author José M. Ordovás, director of the Nutrition and Genomics Laboratory at the USDA HNRCA at Tufts University.

These findings, Ordovás said, stood in sharp contrast to "the control group following the low fat control diet, where homozygous carriers were almost three times as likely to have a stroke compared to people with one or no copies of the gene variant."

According to the researchers, a Mediterranean diet is one that features olive oil, fish, complex carbohydrates and nuts. In order to determine how closely participants adhered to the diet prior to the trial, the authors examined their responses to a series of questionnaires.

"Again, we saw that the Mediterranean diet appeared to compensate for genetic influence," said Dolores Corella of the CIBER Fisiopatologia de la Obesidad y Nutriciόn and the Genetic and Molecular Epidemiology Unit at the University of Valencia. "If adherence to the diet was high, having two copies of the gene variant had no significant influence on fasting glucose levels."

This was true, she further explained, in the case of total blood cholesterol, low density lipoprotein and triglycerides -- all of which are common measures of cardiovascular disease risk.

"Conversely," Corella said, "these risk factors were considerably higher in homozygous carriers with low adherence to the diet."

Going forward, Ordovás argues that, "With the ability to analyze the relationship between diet, genetics and life-threatening cardiac events, we can begin to think seriously about developing genetic tests to identify people who may reduce their risk for chronic disease, or even prevent it, by making meaningful changes to the way they eat."