In a new study, they found foods rich in olive oil help to enhance the benefits of so-called 'good cholesterol..
Just four tablespoons of the widely used ingredient each day prevented plaque from forming in the arteries of those deemed at risk.
However, it didn't help to reduce levels of 'bad' cholesterol, a known risk factor of heart attacks and stroke. Researchers from Hospital del Mar Medical Research Institute in
They were randomly assigned to one of four possible diets: a Mediterranean diet with virgin olive oil, a Mediterranean diet enriched with a fistful of extra nuts or a healthy 'control' diet. The latter had a reduced consumption of red meat, processed food, high-fat dairy products and sweets. In addition to emphasising fruit, vegetables, legumes and whole grains, both Mediterranean diets included moderate amounts of fish and poultry.
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Blood samples were taken at the start of the study, which was published in Circulation, and a year later. They found only the control diet reduced levels of 'bad' cholesterol low-density lipoproteins.
None of the diets were found to increase HDL levels, but both Mediterranean diets did improve the function of good cholesterol.
But the improvement was much larger in those who had the extra virgin olive oil the equivalent to four tablespoons. This included boosting its ability to remove plaque in the arteries and making blood vessels more relaxed.
Study author Dr Montserrat Fitó said: 'Following a Mediterranean diet rich in virgin olive oil could protect our cardiovascular health in several ways, including making our "good cholesterol" work in a more complete way.'