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We're sorting out some health food claims this morning, like kombucha. Is this fermented brew really good for you? We'll find out in a moment. But first, olive oil. The truth: not all oils are created equal.
NPR's Allison Aubrey reports on what you need to look for to make you've got the good stuff.
ALLISON AUBREY, BYLINE: If you pay any attention to health trends, you've likely heard about the Mediterranean diet. This is a pattern of eating that includes lots of vegetables, grains and fish - not so much meat - and generous portions of olive oil.
MARY FLYNN: Olive oil is a very healthy food. I consider it more medicine than food.
AUBREY: That's Mary Flynn. She's an associate professor of medicine at Brown University. And she says the evidence that olive oil is good for your heart has never been more clear. She points to a big study published earlier this year in the New England Journal of Medicine, where researchers in Spain had men and women in their 50s, 60s and 70s who were at risk of heart disease follow one of three diets. Some ate a low-fat diet. Another group ate a Mediterranean diet with nuts. And a third group ate a Mediterranean diet that included nearly four tablespoons of extra-virgin olive oil per day.
FLYNN: So, they could compare the three diets: Was it nuts, was it olive oil, or was the low fat diet as beneficial?
AUBREY: And what researchers found was that a Mediterranean diet rich in olive oil cut the risk of heart attack and strokes by about 30 percent. Researchers even stopped the study early, since the benefits were so clear.
TOM MUELLER: The fact is, there are a huge range of different health benefits of real extra-virgin olive oil.
AUBREY: That's Tom Mueller. He has spent the last six years investigating and writing about olive oil. He says olive oil is good for two reasons. It's mostly unsaturated fat, and extra-virgin oil - which is the highest-grade and least-processed form of olive oil - contains a whole range of other beneficial plant compounds called polyphenols. But here's the catch: Unfortunately, it turns out that more than half of the extra-virgin olive oil imported into the U.S. has been shown to be sub-standard.
MUELLER: It's quite often just very low-grade oil that doesn't give you the health benefits and doesn't give you taste of that extra-virgin should give you.
AUBREY: In fact, a study from UC Davis found that 69 percent of imports tested failed to meet a USDA quality standard. And Mueller says, in some cases, the oil is just too old. By the time the imported olive oil reaches us, it's often been shipped from place to place, and sometimes not stored well. And even if it isn't noticeably rancid, many of the heart-healthy compounds have degraded or fizzled out.
MUELLER: Extra-virgin olive oil is fresh-squeezed olive juice. It's a fruit juice. Therefore, freshness is a critical question.
AUBREY: Mueller says the FDA used to police olive oil imports to ensure producers were meeting quality and freshness standards. But those efforts have fallen off. So where does that leave those of us who want to get our hands on the healthy stuff? Well, for starters, Mueller says look for brands that carry a harvest date on the bottle. California Olive Ranch oil - which is sold in lots of chain supermarkets nationwide - has a date clearly stamped on the back of the bottle.
I met up with Gregg Kelley of California Olive Ranch at a Safeway grocery store.
GREGG KELLEY: So this is a harvest date. Every single bottle produced by California Olive Ranch includes the date the olives were harvested to produce the oil in the bottle.
AUBREY: And he says the olives were pressed very quickly, so the oil is really fresh.
KELLEY: The most important thing for consumers to remember when they're purchasing extra-virgin olive oil is it is not wine. It does not get better with age. So olive oil never gets better than the day it was produced.
AUBREY: Now, as long it's properly stored, the freshness will hold in the bottle, at least for a while. Some bottles now carry an expiration date. But as soon as you open the bottle and expose the oil to oxygen and light, it will slowly start to degrade. So Tom Mueller says don't make the same mistake his family made.
MUELLER: I grew up with terrible oil. I grew up with a huge tin in my grandparent's cabin, and that was olive oil for me. And it was moldy and fusty, and it was there for years.
AUBREY: Many factors determine how quickly an olive oil goes bad. But studies suggest once you've opened it, you should consume it within four to six months.
Now, oils with the highest levels of heart-healthy compounds tend to be pungent and peppery. And Mueller says if the oil stings the back of your throat a little, that tells you that those beneficial polyphenols really are there. I got the chance to experience this during a tasting of fresh imported oils at Greg Bonaduce's(ph) olive oil shop in Brooklyn.
GREG BONADUCE: You ready?
BONADUCE: This is an organic Coratina, and it was grown in Peru, and it was just crushed in April.
AUBREY: We did feel that tickle, and it made us both cough.
BONADUCE: That pungency...
(SOUNDBITE OF COUGHING)
BONADUCE: This is definitely a two-cougher.
AUBREY: And Mueller says that's what you're looking for.
MUELLER: Once you have that taste, you get used to the little bitterness and the little pungency, you never go back. It's a completely different experience.
AUBREY: And the healthy one, too.
Allison Aubrey, NPR news.