A new study further strengthens the notion that what you eat can have an impact on your genetic risk for disease.
The research, published in the journal Diabetes Care, shows that for people who carry two copies of a specific gene variant known to raise disease risk, eating a Mediterranean diet seems to lower their risk of developing stroke -- to the level of someone who possesses just one copy, or no copies, of the gene variant. A Mediterranean diet is one that is high in olive oil, fish and produce.
On the other hand, for people who carry two copies of this gene variant and eat a low-fat diet, their risk of stroke is nearly three times higher than people with one or no copies of the gene variant.
"Our study is the first to identify a gene-diet interaction affecting stroke in a nutrition intervention trial carried out over a number of years in thousands of men and women," study researcher José M. Ordovás, Ph.D., director of the Nutrition and Genomics Laboratory at the USDA Human Nutrition Research Center on Aging at Tufts University, said in a statement.
"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," Ordovás added.
The study involved more than 7,000 men and women who were part of the Prevencion con Dieta Mediterranea trial, who researchers assigned to eat either a Mediterranean diet or a low-fat diet for nearly five years. They were monitored to see if they had a heart attack or stroke, or developed heart disease, over the study period, and their adherence to the assigned diets was monitored via food frequency questionnaires.
Researchers also looked to see if the study participants carried a variant on the Transcription Factor 7-Like 2 gene; this variant is known to play a role in Type 2 diabetes risk, but researchers didn't know if it also affected heart disease risks. They found that 14 percent of the study participants had two copies of this gene variant (known as homozygous carriers of the gene variant), putting them at a higher risk for disease.
In addition to finding that abiding by a Mediterranean diet seemed to lower stroke risk among people with two copies of the genetic variant, researchers also found that it seemed to have positive effects on fasting glucose levels and other measures of heart disease risk.
Earlier this year, a large study published in the New England Journal of Medicine showed that a Mediterranean style of eating could lower stroke risks among people who are at high risk for the condition. This study also involved assigning people to eat a Mediterranean diet or a low-fat diet.