Researchers may have pinned down one important reason for the positive effect olive oil appears to have on cardiovascular health: it contains a naturally occurring anti-inflammatory chemical.

The substance, which the researchers call oleocanthal, has the same anti-inflammatory effect as drugs like ibuprofen and aspirin, which can inhibit the sometimes harmful effects of enzymes called cox-1 and cox-2.

The report appears in the Sept. 1 issue of Nature.

Scientists have long known that low-doses of the cox inhibitors confer various benefits on the people who use them.

Now, the researchers are speculating that the health benefits that are widely linked to the Mediterranean diet, which is rich in olive oil in various forms, may stem at least in part from the same mechanism.

"There is ample evidence that chronic low-dose anti-inflammatories have multiple health benefits that may range from reducing the risk of heart disease, stroke and certain cancers - breast, lung, colon - to reducing the risk of terminal dementias such as Alzheimer's," said Paul A. S. Breslin, who is a co-author of the report and a researcher at the Monell Chemical Senses Center in Philadelphia.

"Olive oil contains an ibuprofen-like anti-inflammatory that may turn out to convey similar benefits," he continued.

The extra-virgin olive oil, according to Dr. Breslin, has the most benefit, but consumers do not necessarily need to buy the most expensive brands.

"What matters is that it is an extra-virgin olive oil that has a good throat sting indicating it has high levels of oleocanthal," he said.

Dr. Breslin suggested that the Mediterranean diet - with extra-virgin olive oil used liberally on bread and vegetables and in salad dressing - may be the best way to consume it.

"If used this way," he said, "I think it will be good for you, particularly if it substitutes for butter, margarine and creamy dressings."

New York Times