Studies have shown that a traditional Mediterranean diet with olive oil can be associated with lower heart disease risks. A Spanish study may have found out why – olive oil, in part, helps maintain healthy blood flow and cleans out the arteries.
Dr. Alvaro Hernaez of the Hospital del Mar Medical Research Institute in Barcelona, lead author on the study, said,
A Mediterranean diet rich in virgin olive oil improves the function of high-density lipoproteins, HDL, popularly known as ‘good’ cholesterol.
A Mediterranean diet usually contains plenty of legumes and fruits that are rich in antioxidants, as well as whole grains, vegetables and olive oil. It also favors lean protein like chicken or fish, The Huffington Post reports.
Hernaez wrote in an email, “Our hypothesis is that these dietary antioxidants may bind to HDL particles and protect them against different kinds of attacks. As HDLs are more protected, they can perform their biological functions more efficiently and, therefore, they are able to remove cholesterol from arteries or contribute to the relaxation of blood vessels for longer.”
The researchers examined data on 296 adults who were 66 years old on average. They were at a higher risk for cardiovascular disease, and were randomly assigned to three diets: a Mediterranean diet with an additional one liter of extra virgin olive oil per week, a Mediterranean diet supplemented by 30 grams of nuts a day, or a low-fat diet.
The participants were told to follow their diet for a year. In the end, only those on the low-fat diet showed reduced LDL – low density lipoproteins (LDL) or “bad” cholesterol, and lower cholesterol levels in general.
None of the diets showed a significant increase in HDL levels. But blood tests and lab work showed that there was a better HDL functioning in the group that consumed the extra olive oil.
Still, these findings add to the growing body of research suggesting that HDL function may indeed lower cardiovascular disease risks, according to Dr. Daniel Rader of the University of Pennsylvania in Philadelphia.
Rader, who wrote an accompanying editorial to the study, said, “We know the Mediterranean diet reduces risk of heart disease but still don’t know exactly why. There is probably more than one reason, and this study suggests that one mechanism might be that the Mediterranean diet improves the function of HDL.”