You have another reason to put olive oil on your salad – protection from hypertension. Putting olive oil on vegetables may bring health benefits that are not found when the oil is drizzled on other foods, research suggests. “The findings explain why Mediterranean diet supplemented with extra-virgin olive oil or nuts can reduce the incidence of cardiovascular problems like stroke, heart failure and heart attacks,” explained professor Philip Eaton from King’s College London.

The Mediterranean diet typically includes unsaturated fats found in olive oil, nuts and avocados, along with vegetables like spinach, celery and carrots that are rich in nitrites and nitrates. When these two food groups are combined, the reaction of unsaturated fatty acids with nitrogen compounds in the vegetables results in the formation of nitro fatty acids. The researchers used mice to investigate the process by which these nitro fatty acids lower blood pressure.

They looked at whether they inhibited an enzyme known as soluble Epoxide Hydrolase which regulates blood pressure. During the study, nitro fatty acids were found to lower the blood pressure of normal mice following the same diets. “The protective effect of the Mediterranean diet comes at least in part from the nitro fatty acids generated which inhibit soluble Epoxide Hydrolase to lower blood pressure,” Eaton maintained. The findings, published in the journal PNAS, help explain why some previous studies have shown that a Mediterranean diet can reduce blood pressure.