Scientists say they have discovered that the Mediterranean diet may prevent a genetic risk of stroke since it appears to interact with a particular gene variant usually associated with type 2 diabetes.
Researchers from the Jean Mayer USDA Human Nutrition Research center on Aging (USDA HNRCA) at Tufts University, and the CIBER Fisiopatología de la Obesidad y Nutricion in Spain, conducted the study, which was published in the journal Diabetes Care.
The research team analyzed 7,018 men and women involved in the Prevencion con Dieta Mediterranea (PREDIMED) trial. The trial, carried out over a 5-year period, looked at whether a Mediterranean or a low-fat controlled diet had an effect on the risk of cardiovascular disease, stroke and heart attack, and whether genetics played a part in this.
Prior to the trial, participants were also required to complete food frequency questionnaires, in order to see how closely participants followed a Mediterranean diet.
The study focused on a particular variant found in the Transcription Factor 7-like 2 (TCF7L2) gene. The variant is commonly involved in glucose metabolism and can lead to the development of type 2 diabetes. The researchers say this gene variant's link to heart disease has previously been unclear.
Around 14% of the PREDIMED participants were found to be homozygous carriers, meaning they possessed two copies of this gene variant.
Of these homozygous participants who were also following the Mediterranean diet, results of the analysis revealed a reduced number of strokes. José Ordovás, director of the Nutrition and Genomics Laboratory at the USDA HNRCA, explains:
"Being on the Mediterranean diet reduced the number of strokes in people with two copies of the variant.
The food they ate appeared to eliminate any increased stroke susceptibility, putting them on an even playing field with people with one or no copies of the variant."
However, Ordovás adds that homozygous carriers who were following the low-fat diet did not have the same results, with a three times increased risk of having a stroke compared with participants with only one or no copies of the gene variant.
Delores Corella, of the CIBER Fisiopatologia de la Obesidad y Nutriciόn, says, however, results showed that when adherence to the Mediterranean diet was high, having two copies of the gene variant bared no significance on fasting glucose levels.
"The same was true for three common measures of cardiovascular disease risk: total blood cholesterol, low density lipoprotein and triglycerides."
"Conversely, these risk factors were considerably higher in homozygous carriers with low adherence to the diet."
Other Mediterranean diet benefits
Previous research has also revealed that following a Mediterranean diet can benefit health. A study from the University of Alabama at Birmingham suggested that following a Mediterranean diet may improve memory and thinking.
Researchers from Spain have suggested the diet may help protect the health of bones.
The Mayo Clinic offers a recommendation of key components that make up a healthy Mediterranean diet. These include:
- Eating primarily plant-based foods, such as fruit, vegetables, whole grains, legumes and nuts
- Replacing butter with healthy fats, such as olive oil
- Using herbs and spices instead of salt to flavor foods
- Limiting red meat to no more than a few times a month
- Drinking red wine in moderation (optional).
The researchers in the current Spanish study would like to see more studies to determine how our genes and the Mediterranean diet work together.