THOSE 'DEMENTIA-PROOF' AMAZON COMMUNITIES ACTUALLY GET DEMENTIA AT OUR RATE

In 2022 the Tsimané and Mosetén walked into international headlines with what looked like the best brains on the planet. Researchers counted five dementia cases among 435 Tsimané and one among 169 Mosetén aged 60 and over, and lead author Margaret Gatz said something about the pre-industrial subsistence lifestyle appeared to be protecting them. Every longevity podcast in America took a victory lap on behalf of hunting, fishing and walking a lot. Then the same team went back. They followed 730 adults who had no dementia at their first assessment and revisited them nearly five years later, and logged 22 new cases at 7.40 per 1,000 person-years, with incidence similar to Western populations before age 80. "The surprising finding was that there weren't big differences in dementia incidence," Gatz said. Prevalence stayed under 2% partly because dementia there came with more than six times the mortality. Limited medical care makes treatable infections and other acute illnesses more deadly. It also isn't the Alzheimer's you're picturing. Blood work linked cases to neurofilament light chain, a general marker of neurodegeneration, and not to amyloid or phosphorylated tau, and many affected people had more trouble with attention, reasoning and managing tasks than with memory. The heart-healthy theory took a hit too, since research in these communities hasn't found that better metabolic health means lower dementia risk. The authors caution that 22 cases are too few to explain everything, and new-case rates were still modestly lower than in many US and European studies, so survival isn't the whole answer either.

Why you should give a shit: Every guy selling you a forager diet was quoting a number that only looked miraculous because survival after diagnosis is short, which makes it a health care gap, not a hack.