Rogue pine nuts can spoil your appetite for weeks

By Denise Ryan
Postmedia News
May 6, 2011

It's the sort of thing that could drive you crazy: Your tongue tastes like tin foil, or raw metal. Everything you eat tastes bitter.

The mysterious condition has a name: "pine nut syndrome", or "pine mouth", and appears to be caused by the tiny, teardrop shaped kernel that is as famous for its aphrodisiac qualities as it is for its priciness.

Eat the wrong one and suddenly everything you eat or drink will taste like you sucked it through the toilet pipe.

The problem has a medical name: metallogeusia, and since 2009, when PNS complaints spiked, the syndrome has been trending on Google, baffling scientists and annoying epicureans around the globe.

Facebook even has a page, "Damn You Pinenuts."

The disorder typically appears about two days after ingestion of a rogue pine nut, and can last for up to nine weeks.

Larry Stefan, a Vancouver organizational psychologist, has lost two pounds since he was struck by PNS two weeks ago. He simply cannot eat because everything tastes so horrible.

The syndrome hit him a couple of days after he enjoyed some pine nuts sprinkled on a salad.

The nuts, he said, were brought to his home by an "artist friend" who had purchased them at Safeway. "I love them," he said.

The next day, he consumed pine nuts from a different source.

About 48 hours later, Stefan, noticed a tinny, metallic taste to everything, including his own breath.

A wine lover with a 2,500-bottle cellar, Stefan couldn't choke down a glass of good red. It tasted like vinegar.

At first he thought he was ill.

"I thought it could be anything. I could be dying of liver cancer and not know it."

The wine-lover consulted his doctor and nutritionist at a private clinic. His blood work was normal. But nothing else felt normal any more.

"All foods have a bitter flavour. If you breathe through your mouth, the air tastes foul. It's a bitch."

PNS has been identified as an emerging problem in the Journal of Medical Toxicology, and is being actively investigated by the U.K. food standards agency, and EU food safety groups.

A January 2011 report in the Journal of Toxicology suggests that taste disturbances following consumption of pine nuts is related to a species from southern China, the Pinus Armandii (white pine). Chinese white pine, until recently, was harvested only for lumber, resin or turpentine. It is a relative newcomer to the billion-dollar a year global pine nut market.

The Danish food ministry has called nuts from the white pine species "illegitimate."

Although experts have determined that the Pinus Armandii has a slightly different fatty acid profile than other genus, they are baffled as to what actually causes PNS.

Some suppliers are taking action to limit imports from southern China.

"We are very familiar with pine nut syndrome," said Craig Wilson, Vice President of Food Safety and Quality Assurance at Costco, who spoke to The Vancouver Sun from Costco's head office in Issequah.

Wilson has been working directly with the U.S. Food and Drug Administration to try to figure out what causes PNS. "It's a huge mystery."

Craig Wilson said that although he isn't sure the problem is limited or can be blamed on the Pinus Armandii, Costco does not buy pine nuts from those regions in which the Pinus Armandii, or China white pine, grow.

"We are very careful on the variety that we buy, and we're specific about where we get them," said Wilson.

Wilson also said the FDA is actively working with several university research institutes to investigate the problem.

Betty Kelsey, a Safeway spokeswoman in Calgary, said that Safeway is aware of the pine nuts issue, but hasn't changed their supplier or taken the product off the shelf. The origin of the Safeway brand pine nut product is a mixture of European and Chinese varieties.

"This is a product we've been watching with great interest, but there has been no direction from Health Canada yet," said Kelsey.

After repeated requests for an interview, Health Canada would not comment directly on the issue, but emailed this response: "Health Canada is not currently conducting any studies regarding pine nuts. However, Health Canada regularly monitors the latest scientific information available (including scientific information available in other countries) on a broad range of food safety issues, including the risk of eating these pine nuts."

China got into the global pine nut market in a big way about a decade ago, said Penny Frazier, owner of Goods from the Woods, and pinenut.com, and an organic farm in Missouri.

"I stopped working with imported nuts about five years ago," said Frazier.

Not a nut, but a seed, the pignola is a volatile commodity: It is difficult to harvest and shell, she explained, and has a short self life.

The source of a bag of pine nuts can be problematic to trace, as pine nuts are sold in bulk on the global market, and the pack you pick up off the shelf could contain pine nuts from a variety of sources.

Responding to the research linking the China white pine to pine mouth syndrome, the Chinese Tree Nut Association affirmed in December that a variety of pine nut called the Pinus Armandii, from the growing areas of Shaanzi and Shanzi, may be the rogue variety responsible for the wave of complaints among pine nut consumers.

The variety has been called "unfit for human consumption" by the EU food standard authorities.

In a paper presented at a conference in Shenyang, China, in December, authorities stated that not all of the varieties grown in China are problematic, but their group "strongly requests Chinese exporters not to export kernels of variety Pinus Armandii to the EU market."

Pine nuts from the Pinus Armandii genus can be identified with some certainty: They are shorter, and fatter than the longgrain rice shape of the typical European or American variety, shaped more like corn kernels and have a brown tip.

(Greatpinenutmystery.com has a good visual guide to the pine nut, the good, the bad and the metallogeusic).

Stefan, who is "still suffering," will be examining his pine nuts a little more closely in the future -that is if he decides to risk eating them again.

dryan@vancouversun.com

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