A study of twins shows that even with genes that put them at higher risk of cardiovascular disease, eating a Mediterranean-style diet can improve heart function, according to research reported in Circulation: Cardiovascular Quality and Outcomes, an American Heart Association journal.
Using data from the Emory Twins Heart Study, researchers found that men eating a Mediterranean-style diet had greater heart rate variability (HRV) than those eating a Western-type diet. Heart rate variability refers to variation in the time interval between heart beats during everyday life - reduced HRV is a risk factor for coronary artery disease and sudden death.
"This means that the autonomic system controlling someone's heart rate works better in people who eat a diet similar to a Mediterranean diet," said Jun Dai, M.D., Ph.D., study author and assistant professor of nutrition and epidemiology at Indiana University in Bloomington.
Eating a Mediterranean-style diet - one characterized by low saturated fats and high in fish, fruits, vegetables, legumes, nuts, olive oil, cereals and moderate alcohol consumption - reduces a person's heart disease risk. But until now, the way the diet helps reduce the risk of coronary disease remains unknown.
Dai and her colleagues analyzed dietary data obtained from a food frequency questionnaire and cardiac data results from 276 identical and fraternal male twins. They scored each participant on how closely his food intake correlated with the Mediterranean diet; the higher the score, the greater the similarity to a Mediterranean-style diet.
To measure HRV, participants had their heart's electrical activity continuously measured and recorded with a Holter Monitor, a portable, battery operated electrocardiogram device.