Think All Olive Oils are the Same? Not Even Close


Olive oil in bowl photoI go through olive oil faster than any other ingredient, using it on just about anything. I thought I was doing my family a public service with all the omega 6 fatty acids I've been serving up on a daily basis. But recently, I realized that like most seemingly healthy foods, not all olive oils are created equal. In fact, it’s not even close.

Polyphenols are Key

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

It’s the phenolic compounds known as polyphenols found in olive oil, also present in red wine, chocolate, tea, and many fruits and vegetables that make the difference. And when tested, many store bought olive oils had very little polyphenols present. 

One of the polyphenols in olive oil, hydroxytyrosol, helps protect the cells that line our blood vessels from being damaged by overly reactive oxygen molecules. Therefore, it keeps our arteries flowing strong. It’s also 75 percent oleic acid, a monounsaturated fat. 

While olive oil can be beneficial, its qualities make a huge difference. According to Malik on LiveScience, olive oil only has a 2 year shelf life. Older trees produce olives with more polyphenols and green olives have a more potent antioxidant count than ripe olives. And if you’re wondering, ripe olives are actually black olives. Who would have thought that green and black olives actually came from the same plant, considering the flavor is so very different. 

The Heat Factor

And then there’s the heat factor. Olive oil needs to be extra virgin and cold pressed to keep all of its polyphenols in good working order and cooking with extreme heat will kill them off. That’s why it needs to be stored in a cold, dark place. Adding heat in the production process, storing the oil in direct light, or exposing the oil to oxygen will all cause an oil to go bad. Using chemicals in production can definitely hurt the taste of the product, as well as speeding up the deterioration of the oil.

According to Dan Flynn, executive director of the UC-Davis Olive Center, a few tips can really make a difference including looking at the harvest date on the label and looking for a grassy, peppery flavor present in fresh, high quality olive oils.

Photo: iStockphoto/Thinkstock

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Sara Novak writes about health and wellness for Discovery Health. Her work is also regularly featured in Breathe Magazine and on She has written extensively on food policy, food politics, and food safety.









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