New research explains why Mediterranean diet - rich in olive oil - is good for health.
According to researchers at the King's College, London, unsaturated fats from olive oil and nitrite-rich vegetables such as lettuce protect people from hypertension.
Past studies have shown that following Mediterranean diet - consisting of lots of fruits, vegetables, olive oil and a glass of wine - can help people live longer and healthier. The study shows why Mediterranean diet is associated with good heart health.
Vegetables like spinach, celery and carrots are rich in nitrites and nitrates. When these compounds react with unsaturated fatty acids from olive oil, they form nitro fatty acids.
In the current study, researchers wanted to know whether or not nitro-fatty acids lower blood pressure. The team specifically looked at Epoxide Hydrolase - an enzyme that maintains blood pressure.
For the study, researchers bred two kinds of mice; one set was genetically engineered and lacked the mechanism, which controlled blood pressure, meaning that these mice had persistent high blood pressure. The other set of mice was normal.
The team then fed both sets of mice a diet rich in nitro-fatty acid. Researchers found that the diet helped lower blood pressure in normal mice, but not in genetically altered mice.
The study shows that the presence of nitro-fatty acids, which block the activity of Epoxide Hydrolase, might explain the health benefits of following a Mediterranean diet.
Note that Mediterranean diet consists of several cereals, fruits and nuts, meaning that there are several compounds that could be affecting heart health via several mechanisms. The nitrite-unsaturated fat combination explains just one possible reason for the benefit of following the diet.
"The findings of our study help to explain why previous research has shown that a Mediterranean diet supplemented with extra-virgin olive oil or nuts can reduce the incidence of cardiovascular problems like stroke, heart failure and heart attacks," said Philip Eaton, Professor of Cardiovascular Biochemistry at King's College London, according to a news release.
The study is supported by the British Heart Foundation and is published in the journal Proceedings of the National Academy of Sciences.