Pine Nuts May Be To Blame For That Bitter Aftertaste : Shots - Health News Scientists haven't documented any long-term health effects from eating bad pine nuts, just an annoying, temporary metallic taste in the mouth.

Pine Nuts May Be To Blame For That Bitter Aftertaste

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It's MORNING EDITION, from NPR News. Good morning. I'm Renee Montagne.


And I'm Mary Louise Kelly. In Your Health today, we begin with a food mystery, a phenomenon dubbed pine mouth. It's marked by the sudden onset of a metallic or bitter taste in your mouth. It can last anywhere from a few days to a couple of weeks. And as NPR's Allison Aubrey explains, the culprit seems to be pine nuts.

ALLISON AUBREY: Cecily Wilhelmy(ph) thought there might be something off about the blueberries she ate for breakfast last Tuesday morning. She perceived a strong metallic taste that lingered all the way from her breakfast table through her commute to work in suburban Seattle. At the office, after she'd make it through lunch, she realized nothing tasted normal.

Ms. CECILY WILHELMY: Everything else that I ate tasted bitter and metallic, and my mouth tasted that way, as well.

AUBREY: So while Cecily got on the phone to report her symptoms to her doctor, her colleague did a quick online search, typing in the terms metallic or bitter taste. When he got several hits on pine mouth, his first question to Cecily...

Ms. WILHELMY: He said: Have you had pine nuts? And I looked at him as if, are you kidding me? I happened to have had pine nuts, but what does that have to do with anything?

AUBREY: Cecily couldn't believe that a handful of toasted pine nuts that she'd eaten two days before could be responsible for the vile taste. The Internet, after all, can lead us to all sorts of speculations, especially when we try medical sleuthing.

But one item caught her attention. It was an abstract of the scientific paper in the journal of medical toxicology, titled "Pine Mouth Syndrome: An Emerging Problem." The author is an emergency medicine physician at the University of New Mexico whose name is Dr. Marc-David Munk.

Dr. MARC-DAVID MUNK (University of New Mexico): I've had it myself, which is actually what prompted my interest in it.

AUBREY: He came down with the bitter taste after eating pine nuts from a restaurant salad bar last year. It lasted about a week, and he didn't have any accompanying sickness. But as he tried to research the condition, he was surprised by all the anecdotal chatter about pine mouth on websites from the U.S. to Australia and the United Kingdom. After an initial report from a Belgian doctor in 2001, the topic seemed to explode in mid-2009.

Dr. MUNK: The search volume has been incredible high, so just using that as a surrogate, we suspect there's a lot of pine mouth in the country.

AUBREY: Official numbers are hard to come by. The Food and Drug Administration logged 53 complaints last year. Updated numbers are not available. Of the initial reports, two people complained of GI tract illnesses along with the bitter taste. The others, an FDA spokesperson told me, were just considered taste disturbances, not illnesses.

No one knows what's causing the syndrome. For now, physician Marc-David Munk says there are two theories. One is simply that people don't store pine nuts properly, and they go bad.

Dr. MUNK: We know from the agricultural research that pine nut oil is particularly unstable. Some oils tend to do pretty well over long term storage, and other oils go rancid fairly quickly. And pine nut oil is one of those that goes rancid quickly.

AUBREY: So this may explain some cases. The other theory implicates Chinese pine nuts. Researchers in Switzerland recently did a chemical analysis of imported pine nuts and identified two species that have not traditionally been part of the food supply.

Dr. MUNK: One was the Chinese White Pine, and one was the Chinese Red Pine. These are nuts that have never historically been eaten before. The second theory is that, in fact, Pine nut Mouth is actually caused by generally inedible species of pine nut that have now made it onto the market.

AUBREY: The FDA says whenever possible, samples of pine nuts linked to cases of Pine Mouth should be sent to an FDA lab for testing. But so far, there's no evidence to confirm whether Chinese imports or pine nuts gone rancid may be responsible.

Allison Aubrey, NPR News.

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