Bacteria From Guam's Palm Trees Could Unlock a Solution to Alzheimer's

In the mystery of degenerative brain disease, scientists have found a clue in among the most surprising of places: the plant life of Guam.

An environmental toxin produced by bacteria found in Guam's palm trees has been linked to dementia and could potentially help fight Alzheimer's and other neurodegenerative diseases, the BBC reported Thursday. Scientists from the Institute for Ethnomedicine and the University of Miami documented their findings in a study recently published by the United Kingdom's Royal Society.

How did scientists make such an unlikely connection? The discovery was rooted in Guam in the 1950s, when U.S. Army physicians "described a puzzling [Amyotrophic Lateral Sclerosis]-like among the indigenous Chamorro villagers of Guam," the scientists wrote. The mysterious ailment also resembled aspects of Parkinson's disease and Alzheimer's disease, and those afflicted with it tended to have dementia too. "In some villages," the scientists wrote, "one-quarter of the adults perished from the disease."

The illness wasn't genetic. "Since even outsiders who adopted a Chamorro lifestyle experienced an increased risk of illness, a common environmental exposure seemed likely," the scientists wrote.

In the 1960s, experts honed in on a possible cause of the mysterious deaths: beta-N-methylamino-L-alanine, or BMAA, an environmental toxin produced by bacteria found in the roots and seeds of Guam's cycad palm trees. Not only did the Chamorro people use the cycad seeds to make flour, but they also ate fruit bats, which subsisted on the seeds.

Over the course of decades, BMAA emerged as a likelier and likelier culprit. Still, no one had ever collected real, hard evidence that the chronic consumption of BMAA triggered the strange neurodegenerative disease that killed so many Guam villagers.

Until this recent study, that is. For 140 days, the scientists fed fruit laced with BMAA to a group of vervet monkeys, and regular, un-laced fruit to another group of vervet monkeys. At the end of the trial period, the BMAA-ingesting vervets exhibited abnormal "tangles" in their brains — while the vervets who ate regular fruit did not.

"Every single one that had eaten the BMAA bananas developed the brain tangles," researcher Paul Cox said, according to the BBC, "even the cohort given low-dose BMAA."

If the same findings apply to humans, Cox said, "it may be possible to prevent some other neurodegenerative diseases."

Cox and his fellow researchers also found that an amino acid called L-serine "significantly reduced" the density of the brain tangles caused by BMAA. Now, they're running FDA-approved trials to see if "L-serine is a safe and efficacious treatment to reduce disease progression in ALS patients."

Dr. Thomas Wisniewski, director of the Center for Cognitive Neurology at New York University Langone Medical Center, told Mic the study "makes a good case" that the Chamorro people's mysterious ALS-like disease was linked to BMAA. However, "whether this particular toxin, or similar toxins, play a significant role in regular Alzheimer's disease is quite another matter," he told Mic. 

That's not to say the BMAA study is worthless in the fight against Alzheimer's disease. The significance of the study, Wisniewski told Mic, is that "it's pointing to what pathways might be important in driving Alzheimer's-related pathology."

The study could also help find the root causes of other highly specific cases of neurodegenerative disease, such as the increased incidence of ALS symptoms among military veterans. "Maybe this could be related," he said, "an analogous ... toxin they were exposed to," similar to BMAA.

It's a welcome advancement. Currently, no medicine exists to effectively cure any neurodegenerative disease, according to the Institute for Neurodegenerative Diseases.