In a new study from…, researchers found that the Tsimane indigenous people of the Bolivian Amazon experience less brain atrophy than their American and European peers.
The decrease in their brain volumes with age is 70% slower than in Western populations. Accelerated brain volume loss can be a sign of dementia.
Although people in industrialized nations have access to modern medical care, they are more sedentary and eat a diet high in saturated fats.
In contrast, the Tsimane have little or no access to health care but are extremely physically active and consume a high-fiber diet that includes vegetables, fish and lean meat.
These findings suggest that brain atrophy may be slowed substantially by the same lifestyle factors associated with a very low risk of heart disease.
In the study, the team enrolled 746 Tsimane adults, ages 40 to 94.
They used brain scans to calculate brain volumes and then examined their association with age for Tsimane. Next, they compared these results to those in three industrialized populations in the U.S. and Europe.
The scientists found that the difference in brain volumes between middle age and old age is 70% smaller in Tsimane than in Western populations.
This suggests that the Tsimane’s brains likely experience far less brain atrophy than Westerners as they age; atrophy is correlated with risk of cognitive impairment, functional decline and dementia.
The researchers note that the Tsimane have high levels of inflammation, which is typically linked to brain atrophy in Westerners. But their study suggests that high inflammation does not have a pronounced effect upon Tsimane brains.
According to the team, Tsimane’s low heart risks may outweigh their infection-driven inflammatory risk, raising new questions about the causes of dementia.
One possible reason is that, in Westerners, inflammation is linked to obesity and metabolic causes whereas, in the Tsimane, it is driven by respiratory, gastrointestinal, and parasitic infections.
Infectious diseases are the most prominent cause of death among the Tsimane.
The team says the sedentary lifestyle and diet rich in sugars and fats may be accelerating the loss of brain tissue with age and making us more vulnerable to diseases such as Alzheimer’s.
The Tsimane can serve as a baseline for healthy brain aging.
The indigenous Tsimane people captured scientists’ — and the world’s — attention when an earlier study found them to have extraordinarily healthy hearts in older age.
That prior study showed that Tsimane has the lowest prevalence of coronary atherosclerosis of any population known to science and that they have few heart disease risk factors.
The very low rate of heart disease among the roughly 16,000 Tsimane is very likely related to their pre-industrial subsistence lifestyle of hunting, gathering, fishing, and farming.
If you care about dementia, please read studies about this common brain disease can cause dementia and stroke and findings of statin and blood pressure drug combos may help reduce dementia risk.
For more information about dementia and your health, please see recent studies about if your memory feels like it’s not what it once was, it could mean future dementia and results showing that an aspirin a day does not keep dementia at bay.
The study is published in the Journal of Gerontology, Series A: Biological Sciences and Medical Sciences. One author of the study is Andrei Irimia.
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