What's in Your Olive Oil?

Experts share smart shopping and cooking tips.

Medically Reviewed by Laura J. Martin, MD on January 05, 2012
From the WebMD Archives

Olive oil is touted for its health benefits in many diet books and recipes. But is it really the nectar of the gods that it’s made out to be -- and is the olive oil in your pantry as healthy as you think it is?

In his book Extra Virginity: The Sublime and Scandalous World of Olive Oil, author Tom Mueller claims that much of the olive oil sold in the U.S. as "extra-virgin" is really adulterated in some way and lacks the health and the taste benefits of real “extra-virgin” olive oil.

olive oil and olives

So what can you believe, and what's hype? Here are answers.

Olive oil may be one of the more healthful oils out there, but it's still a fat and should still be used in moderation.

Olive Oil Basics

Olive oils are graded based on their extraction process and on the acidity of the pressed oil, says Timothy Harlan, MD, assistant professor of clinical medicine at Tulane University and the author of Just Tell Me What To Eat!

True extra-virgin olive oil (EVOO) is extracted from olives using only pressure, a process known as cold pressing. "Extra-virgin olive oil has just 1% acid. It’s the oil that comes from the first pressing of the olives, and is considered the finest, having the freshest, fruitiest flavor," Harlan says. Virgin olive oil also comes from the first pressing, and has about 3% acid."

In addition to “virgin” and “extra-virgin,” you might also see one of these descriptions on the bottle:

  • Fino: a blend of extra-virgin and virgin oil
  • Light: an oil that has been filtered to remove much of the sediment. ("Light," in this case, has nothing to do with fat or calories. It only refers to color.)
  • Pure: a combination of refined virgin and extra-virgin oils

What You See Isn’t Always What You Get

Unfortunately, you can’t always rely on what the bottle says, says Ruth Mercurio, a board member of the California Olive Oil Council. The U.S. government doesn’t regulate the labeling of extra virgin olive oil.

"Many olive oils claim to be virgin, extra-virgin, or light extra-virgin, but they don't in fact meet the standards of a true extra-virgin olive oil," she says.

What’s more, Mercurio adds, if the label says "Packaged in [name of a country]" (such as Spain or Greece), it’s more than likely that the oil wasn’t grown in that country, just bottled there to give it more cachet. And if there’s no harvest date on the label, you run the risk of purchasing an old, possibly rancid oil. True EVOO has a shelf life of only 18-24 months.

Like a Virgin?

How can you tell if the olive oil on your shelf is reallyextra-virgin? Check the bottle for a label from the North American Olive Oil Association (NAOOA), a trade group that tests olive oils to see if they measure up to the manufacturer’s claims. The trade group tests olive oils to determine if they are what the labels say they are -- and not adulterated or a mislabeled product. The International Olive Council (IOC) is the worldwide body that sets quality standards for the olive oil industry.

Chefs and culinary experts, however, say the best bet is to do a little testing of your own."Pour a few tablespoons of olive oil on a white dish," says Stella Metsovas, a Los Angeles nutritionist. “Look for consistencies that are smooth, although far thicker than corn or vegetable oil. Your olive oil should also smell like olives.

"When the oil hits your palette, look for a smooth finish on the tongue. When the oil hits the back of your throat, look for a slight burn. The burn is actually the polyphenols [a type of antioxidant] found in fresh oils.”

Harlan has some preferences of his own. "I prefer Spanish oils because they will have a grassy and sharper flavor (they are often slightly more acidic). They are often the more reasonably priced choice," he says. "Greek and Italian oils are great. I look for extra-virgin oils that are labeled 'cold pressed' with labels that indicate the origin -- usually a family company or farm."

How to Cook With Olive Oil

When the recipe calls for olive oil, keep this in mind:

  • Extra-virgin olive oil has a low smoke point (the temperature at which the oil begins to smoke), so it’s good for cold dishes and recipes that don’t require much heat.
  • Virgin olive oil is good for lower-temperature cooking. "[It has] great flavor with a higher smoke point," Harlan says.
  • And remember: The healthy phenols found in olive oil are severely compromised by heat, Metsovas says.

Too Much of a Good Thing

Even if you're using the best-quality oils, you can get too much of a good thing. Olive oil may be one of the more healthful oils out there, but it's still a fat and should still be used in moderation.

WebMD Feature



Timothy Harlan, MD, assistant professor of clinical medicine, associate chief professor of outpatient program, Tulane University School of Medicine, New Orleans.

Ruth Mercurio, California Olive Oil Council board member; co-owner, We Olive LLC, San Diego.

Statement from Bob Bauer, president, North American Olive Oil Association.

Stella Metsovas, clinical nutritionist, Los Angeles.

Brenes, M. Journal of Agricultural and Food Chemistry, 2002.

Nash, D. Arteriosclerosis, November-December 1990.

Harlan, T. Just Tell Me What to Eat! The Delicious 6-Week Weight Loss Plan for the Real World, Da Capo Lifelong Books, 2011.

Mueller, T. Extra Virginity: The Sublime and Scandalous World of Olive Oil, W.W. Norton, 2013.

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