Considering the many – and well-studied – health benefits associated with the Mediterranean diet, relatively little is known about the molecular basis behind the benefit. Among other advantages, the diet has been linked to reduced risk of cardiovascular disease, and now, researchers are discovering, on the genetic level, just why this might be the case.
The short answer: Olive oil. Though fats are considered by many to be taboo, olive oil can contain high amounts of compounds called phenols, which have been linked in previous studies to lowered risk for cardiovascular disease. The researchers of a recent study, led by Francisco Perez-Jimenez from the University of Cordoba, Spain, wanted to see what kinds of changes high-phenol content olive oil might bring about at the molecular level.
The researchers found that there were 98 genes that were expressed differently in the high- vs. low phenol consumers. And of these, several genes associated with inflammation in the body were suppressed in the participants who ate the breakfasts high in phenol content.
To study the question, the researchers followed 20 patients with metabolic syndrome, which is a known precursor of heart problems. The participants were asked to avoid all supplements, including vitamins, for six weeks before the study began, in order to eliminate any lingering effect that they might have. Additionally, they were asked to eat similar, low-fat, high-carb diets throughout the study, to avoid any other potential effects of diet on cardiovascular health. But the real variable of interest was the addition of olive oil to the diet: participants ate breakfasts that were high in one of two types of virgin olive oil – one was rich in phenol content and one was low in phenols.
The researchers conclude by saying that their “results provide at least a partial molecular basis for risk reduction of cardiovascular disease observed in Mediterranean countries, where [virgin olive oil] represents a main source of dietary fat. Admittedly, other lifestyle factors are also likely to contribute to lowered risk of [cardiovascular disease] in this region.”
The study was published in the April 20, 2010 issue of BMC Genomics.