You feel good about using olive oil, right? You know it's good for you, tasty and easy to use. Still, to get the most benefits - and the best bang for your buck - there's more you should know.

"The health benefits of olive oil are 99 percent related to the presence of the phenolic compounds, not the oil itself," says Nasir Malik, research plant physiologist at the U.S. Agriculture Department's Agricultural Research Service.

Malik is referring to the polyphenols in olive oil, nutrients also found in wine, tea, cocoa and many fruits and vegetables that have been discovered over the past decade to be the substances responsible for the bulk of olive oil's health benefits, without which "you might as well use canola oil," Malik says.

And when tested, polyphenols were surprisingly low in most commercially available olive oils, according to a recently published study conducted by the Agricultural Research Service, co-authored by Malik.