Mediterranean Diet Trims Genetic Stroke Risk

A gene variant strongly associated with development of type 2 diabetes mellitus appears to respond to a Mediterranean diet to prevent stroke, according to a new study that advances the field of nutrigenomics.

“Stroke, like most complex diseases, has a strong genetic component that affects the disease directly or its risk factors, like diabetes and hypertension. In this particular case, a gene variant strongly associated with development of type 2 diabetes increases the risk of stroke up to 3 times in the general population,” Jos M. Ordovs, PhD, Director, Nutrition and Genomics, at Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, told ConsultantLive.

“But individuals who carry the risk variant and consume a Mediterranean diet pattern have the same risk of stroke as those who don’t carry the risk variant,” he noted. “The Mediterranean diet appears to compensate and remove the added risk.”

The study is the first to identify a gene-diet interaction affecting stroke in a nutritional intervention trial carried out over a number of years in thousands of men and women.

Based in Spain, the randomized, controlled Prevencion con Dieta Mediterranea (PREDIMED) trial enrolled more than 7000 men and women assigned to a Mediterranean or low-fat control diet and monitored them for cardiovascular disease (CVD), stroke, and heart attack for almost 5 years. “This study is a much needed proof-of-concept to push forward the concept of personalized medicine and, in this particular case, personalized prevention based on nutrition,” said Dr Ordovs.

“As more of these large-scale studies are completed and more genes and gene-diet interactions are identified, researchers will be able to compile the data to understand more about the relationship between nutrition, genetics, and health,” Dr Ordovs stated. “Once the data are compiled, genetic tests could be developed to help identify people who may reduce their risk for chronic disease, or even prevent it, by making meaningful changes to the way they eat.”

The researchers focused on a variant in the Transcription Factor 7-Like 2 gene, which has been implicated in glucose metabolism, but its relationship to CVD risk has been uncertain. Being on the Mediterranean diet reduced the number of strokes in persons with 2 copies of the variant. However, in a control group that followed the low-fat diet, homozygous carriers were almost 3 times as likely to have a stroke compared with persons who had 1 or no copies of the gene variant.

“The Mediterranean diet appears to be consistent with a healthy diet, but some may benefit even more than others,” said Dr Ordovs. Primary care physicians should encourage their patients to incorporate as many components as possible of the Mediterranean diet in their menus, he suggested.

“This diet has been shown to reduce the risk of cardiovascular diseases in the population at large,” Dr Ordovs said. “Until we can personalize dietary advice based on reliable genetic information, the Mediterranean diet should take a relevant position among the dietary recommendations aimed to maintain good health and prevent the risk of chronic diseases.”

The researchers presented their results online on August 13, 2013, in the journal Diabetes Care.