A fungus linked to cases of ALS

In a quiet Alpine village, a decades-old medical mystery has finally found an unsettling answer. After years of puzzling over a spike in a rare neurodegenerative disease, researchers have traced the cause back to something that might be sitting on your dinner plate — a wild mushroom with a dangerous secret.

A small village, a worrying pattern

Back in 2009, in Montchavin — a picturesque spot in the French Alps — a local GP noticed something deeply troubling: she had diagnosed amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, in three unrelated patients. In a village this small, that wasn’t just a coincidence — it was a red flag.

That discovery sparked a full-scale medical investigation. Over the course of a decade, researchers uncovered 14 confirmed cases of ALS between 1991 and 2013 — many of whom had already passed away. These individuals ranged from 39 to 75 years old, were not biologically related, but all lived in close proximity and, crucially, knew each other.

A familiar clue from halfway across the world

With no genetic link between the patients, researchers turned to environmental factors. They tested everything: water quality, soil contamination, air pollution, even levels of radon and heavy metals in homes. Nothing pointed to a culprit.

Then came a breakthrough — not from France, but from Guam. Decades ago, the Pacific island had experienced a similarly mysterious surge in ALS cases. There, scientists eventually linked the condition to the traditional consumption of cycad seeds, which are toxic. The connection caught the attention of Dr Peter Spencer, a neurotoxicologist from Oregon Health & Science University, who had studied the Guam cases.

But Montchavin wasn’t eating cycads. So what was the link?

The mushroom with a hidden danger

Spencer and his Franco-American team began to explore a local culinary habit: eating wild mushrooms. One species stood out — the false morel (Gyromitra gigas), a mushroom that resembles the prized true morel but is notorious for its toxicity.

Despite being banned from sale in France since 1991, false morels still find their way into kitchens — especially among locals accustomed to foraging. Several of the ALS patients recalled consuming the mushrooms multiple times in the past, often in hearty meals that included both true and false morels.

The toxic compound in these mushrooms bears a striking similarity to the neurotoxins found in cycad seeds. It attacks the nervous system in ways scientists are only beginning to fully understand. Importantly, none of the unaffected villagers reported eating the false morel — making the connection even more compelling.

An unsettling pattern in Finland

Montchavin isn’t alone. In Finland, where the false morel is still considered a delicacy, researchers have noted a similar uptick in ALS diagnoses in regions where the mushroom is popular.

Meanwhile, on Guam, where cycad seeds have been largely removed from the local diet, the number of ALS cases has dropped significantly — further strengthening the theory that certain natural neurotoxins, consumed over time, can contribute to the development of this devastating illness.

What this means for your next meal

The takeaway is both simple and serious: foragers and food lovers need to be cautious with wild mushrooms — no matter how delicious or traditional the recipe may be. The line between edible and poisonous is often a thin one, and in this case, the risk may extend far beyond food poisoning.

While more research is needed to confirm causality, the pattern is clear enough for scientists to urge caution. So if you’re ever offered a plate of foraged mushrooms, it might be worth asking exactly which kind they are. Because in some rare cases, what starts as dinner could lead to far more lasting consequences.

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David Miller

David Miller is an entertainment expert with a passion for film, music, and series. With eight years in cultural criticism, he takes you behind the scenes of productions and studios. His energetic style guides you to the next big releases and trending sensations.