When it comes to heart health, olive oil continues to trump other oils for its ability to protect the heart from failing and arteries from hardening. Portuguese researchers showed that one particular antioxidant in olive oil — DHPEA-EDA — protects red blood cells from damage more than any other part of olive oil.

The discovery could lead to the development of functional oils designed to protect the human body from heart disease. "Now we have identified the importance of these compounds, producers can start to care more about the polyphenolic composition of their oils," said Fatima Paiva-Martins, assistant professor at the Faculty of Sciences at University of Porto in Portugal and lead researcher for the polyphenolic compounds research team.

"These findings provide the scientific basis for the clear health benefits that have been seen in people who have olive oil in their diet," said Paiva-Martins.

It is well known that heart disease is caused partly by reactive oxygen, including free radicals, acting on LDL or "bad" cholesterol, which causes hardening of the arteries. Red blood cells are particularly susceptible to oxidative damage because they are the body's oxygen carriers.

In the study, published in Molecular Nutrition & Food Research, Paiva-Martins and colleagues compared the effects of four related polyphenolic compounds on red blood cells subjected to oxidative stress by a known free radical generating chemical.

DHPEA-EDA was the most effective and protected red blood cells even at low concentrations. The researchers said the study provides the first evidence that this compound is the major source of the health benefit associated with virgin olive oils, which contain increased levels of DHPEA-EDA compared to other oils. In virgin olive oils, DHPEA-EDA may make up as much as half the total antioxidant component of the oil.

To access the full article: Effects of olive oil polyphenols on erythrocyte oxidative damage; Paiva-Martins, F., et al.