Dispelling the 'killer mushroom' myth

BIOLOGIST Jianping Xu of McMaster University (Hamilton, Ontario) trekked over 30 kilometers a day through mountainous terrain and inclement weather in southwestern China to discover that a wild mushroom was thought to be at the root of 400 unexplained deaths in the region over the past 30 years. His findings, published online in Applied and Environmental Biology, shattered a myth started by a 2010 article in the journal Science, claiming the Trogia venenata mushroom contained high concentrations of the metal barium, causing high blood pressure, cardiac arrests and sudden deaths.

The deaths mainly occurred in small villages, some of which saw nearly one-third of their population perish quickly. “Although there was no published evidence supporting the theory that barium in the T. venenata mushroom was the leading culprit of what was called Sudden Unexplained Death (SUD), it was picked up as a fact by almost all of the major news media,” said Xu, associate professor of biology and a member of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University. “These reports caused significant concern among the public about potentially high levels of barium in wild edible mushrooms in southwest China.”

Every summer since 2009, Xu and his team have travelled across the Yunnan province, collecting fruiting bodies of T. venenata as well as other mushrooms from villages severely impacted by these deaths.

Researchers tested the mushrooms and found the barium concentration was so low it would require a person weighing 150 pounds to consume at least 35 kg of dried T. venenata for it to be lethal. In fact, the barium concentration in these mushrooms is the same as in common foods, such as fresh meat and poultry.

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