If you love wild mushrooms in your risotto, you might want to keep reading before your next foraging adventure. A longstanding medical mystery in a small French village has linked a common wild mushroom to several cases of ALS, sparking both alarm and a decade of investigation. Should you be worried? Let’s untangle this curious story—no rubber gloves required.
A Village Gripped by Mystery
It all started in Montchavin, a picturesque village near the La Plagne ski resort in Savoie. In 2009, a local GP noted something peculiar: for the third time, she diagnosed a local resident with amyotrophic lateral sclerosis (ALS)—also called Charcot’s disease. ALS is a rare, fatal neurodegenerative condition, and having three cases in such a short period within one village was more than eyebrow-raising. Raising the alarm, she contacted specialists, who soon uncovered that between 1991 and 2013, twelve cases had emerged in the village—and, distressingly, half of those patients had already passed away.
The oddity didn’t stop there. Montchavin isn’t a sprawling metropolis; the affected individuals ranged from 39 to 75 years old, had no family ties, but all knew each other well. Coincidence? The story begged for a Sherlock Holmes—preferably one who enjoyed a good mushroom stew.
The Search for an Environmental Culprit
With familial causes ruled out, investigators turned their gaze to the environment. They combed through possible suspects:
- Bacterial toxins
- Lead traces in the water
- Radon gas in homes
- Pesticide or heavy metal pollution in the air or soil
Each lead turned out to be a dead end. It seemed as if the cause was hiding in plain sight—or perhaps, on the dinner plate.
A Toxic Suspect: The False Morel
Enter Peter Spencer, a toxicologist from the University of Oregon, with a résumé including a previous investigation on the Pacific island of Guam. There, he had identified a local custom—consuming cycad seeds—as the cause of a high ALS incidence. While no cycads were found in the French Alps, Spencer’s experience prompted him to consider a different, but equally suspicious, local delicacy: the gyromitre géant, better known as the giant false morel (Gyromitra gigas).
What made false morels a viable suspect? They contain toxins similar to those in cycad seeds, acting on the nervous system in an analogous way. Spencer led the charge, re-examining the habits of Montchavin’s residents. The findings, published in the Journal of Neurological Sciences, were telling: all 14 identified ALS patients in the village had eaten the giant false morel repeatedly, often years before their symptoms started. The rest of the villagers, however, hadn’t indulged in these particular wild mushrooms.
For several patients, the memory went beyond just the mushroom’s taste. They recounted serious bouts of illness after hearty meals that mixed real morels with these so-called false ones. Notably, the sale of gyromitres has been banned in France since 1991 due to concerns about their potential toxicity—a law that some, it seems, did not abide by.
A Global Pattern Emerges
The French Alps aren’t alone in their mushroom misadventure. In Finland, a surge in ALS has also been recorded in an area where false morel is a culinary favorite. The evidence isn’t limited to just one region or cuisine.
Meanwhile, back on Guam, banning cycad seeds from the island’s menu led to an impressive drop in ALS cases. This strengthens the case for a link between these plant and fungal toxins and the onset of neurodegenerative diseases—a sobering thought the next time you find yourself eyeing wild mushrooms in the woods or at a farmer’s market.
So, should you panic if you see a false morel on a forest hike? Not quite. But with science pointing its (sometimes trembling) finger at this toxic mushroom, Montchavin’s cautionary tale is a compelling reminder: not every wild gift of nature belongs on our plate, no matter how gourmet it may seem. If you’re planning a dinner party, perhaps opt for store-bought mushrooms and leave the wild foraging to the experts. Your nervous system will thank you—and so will your dinner guests.
Iveta is an aspiring journalist with a passion for storytelling and a deep love for coffee. Always curious and creative, she dreams of sharing stories that inspire, inform, and connect people around the world
