Nov. 11, 2003 (Orlando) -- A Mediterranean diet rich in olive oil and low in red meat can combat inflammation that silently simmers away for years inside blood vessels, lowering the risk of a heart attack, a new study suggests.
Many people have questioned whether previous benefits attributed to the Mediterranean diet were actually due to other lifestyle factors -- such as increased exercise -- in people following this diet. But the study clearly shows that this heart-healthy effect was independent of any other lifestyle factors, including exercise, says Demosthenes Panagiotakos, PhD, lecturer in the department of nutrition and dietetics at Harokopian University of Athens in Greece.
Panagiotakos, who presented the findings at the American Heart Association Scientific Sessions 2003, says that previous studies have suggested that sticking to a Mediterranean diet -- which also emphasizes grains, fish, vegetables, and fruit -- may cut the risk of heart disease by up to 30%.
However, it is not fully understood how the Mediterranean diet exerts its protective effect, he says.
"Some have suggested it lowers blood pressure; others speculate it reduces cholesterol levels. Still others say it is not the diet itself but other characteristics of people who follow the diet, such as a healthy lifestyle."
The new study, which applied a sophisticated statistical analysis to tease out the effects of any confounding lifestyle factors, should help put an end to the debate, Panagiotakos says.
"The Mediterranean diet, independent of any other factor, reduces levels of inflammation related to heart disease risk," he tells WebMD.
Alice H. Lichtenstein, DSc, vice-chairwoman of the AHA's Nutrition Committee, agrees.
"While no one study ever puts an issue to bed, this research offers really strong data that diet makes a difference," she says.
The researchers followed more than 2,200 men and women, aged 18 years to 89 years, without any history or signs of heart disease or stroke. The participants were asked what types of food they ate and how often.
The study showed that the closer their eating habits came to matching the Mediterranean diet, the lower their levels of C-reactive protein, a sign of general inflammation in the bloodstream.
According to Lichtenstein, the heart-healthy benefits most likely came from the Mediterranean diet as a whole, not from specific components.
"People are always trying to say, 'It's the vitamin E, it's the beta-carotene,' or whatever," she says. "And then the next study proves them wrong.
"That's because it is the relative balance of all the vitamins, minerals, and other components of the foods we ate that makes a difference."