Lifestyle of Amazonian Tribe May Hold Key to Slowing Down Aging

Members of the Tsimane tribe in the Bolivian Amazon have the healthiest cardiovascular systems of any recorded population, which in turn increases their brains' resilience to aging and atrophy.

(CN) --- New evidence shows that a group of Indigenous people from the Bolivian Amazon known as the Tsimane experience a 70% slower decrease in brain volume over the course of their lives than adults in Western populations, shedding new light on dementia and neurological health in industrialized regions of the world.

In a new study, published Wednesday in the Journal of Gerontology, Series A: Biological Sciences and Medical Sciences, a group of international scientists performed CT scans on hundreds of adult Tsimane participants and found their elevated cardiovascular health keeps their brains healthy for much longer than those in more modernized nations.

The Tsimane people in Bolivia have recently been recognized by the scientific community as a highly active Indigenous group with above average heart health, and as such they have been looked to for clues on how other populations can lower their chances of developing heart disease. In fact, a similar study published in 2017 in the Lancet found that the Tsimane have the lowest levels of coronary atherosclerosis, or coronary artery disease, of any population ever recorded.

But despite their cardiovascular health, the life expectancy of the Tsimane is just 53 years due to their lack of access to modern health care. They often suffer from disease and infection, especially since they are without plumbing, abundant fresh water and electricity. However, they are approximately five times less likely to develop heart disease thanks to their high-fiber diet of fish, lean meat and vegetables obtained by dedicated fishing, hunting, and foraging. 

In contrast, more modernized populations may have an average life expectancy of 79 to 82 years but they lead a highly sedentary lifestyle and consume large amounts of saturated fats. This puts them at much higher risks for cardiovascular disease, the number one cause of death in the United States and in the world.

"The Tsimane have provided us with an amazing natural experiment on the potentially detrimental effects of modern lifestyles on our health," said co-author Andrei Irimia, an assistant professor of gerontology, neuroscience and biomedical engineering at the USC Leonard Davis School of Gerontology and the USC Viterbi School of Engineering. "These findings suggest that brain atrophy may be slowed substantially by the same lifestyle factors associated with very low risk of heart disease."

The authors were anxious to know how the Tsimane’s exceptionally strong hearts affected other aspects of their health, including their brains’ resilience to aging. They conducted research involving 746 adult Tsimane participants, ranging in age from 40 to 94, and took CT scans of each individual. The authors said that this process involved the transportation of everyone from their remote villages to Trinidad, Bolivia, to undergo the scans, often a two-day trip traveling by rivers and roads. 

After scanning to determine brain volume, or brain size, in accordance with their ages, they compared their results with scans of individuals from three different populations across the U.S. and Europe. The results showed that the difference in brain size between middle aged and older aged brains was 70% less in Tsimane participants than those from the industrialized nations. 

The difference in shrinkage here proves the Tsimane tribe experiences much less brain atrophy than Western populations. This means people from industrialized nations are more likely to suffer significant neuron loss in old age, which can lead to loss of cognitive abilities and in extreme cases, Alzheimer’s and dementia.

"Our 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," said co-author Hillard Kaplan, a professor of health economics and anthropology at Chapman University. "The Tsimane can serve as a baseline for healthy brain aging."

The researchers add the Tsimane are more prone to inflammation due to frequent infections, and while inflammation normally poses a threat of dementia in Western populations, it does not have any significant impact on the Tsimane’s brains. The team suggests this is because inflammation in Westerners is mostly caused by obesity, while inflammation in the Tsimane people is mostly brought on by gastrointestinal, respiratory, and parasitic infections.

"This study demonstrates that the Tsimane stand out not only in terms of heart health, but brain health as well," Kaplan said. "The findings suggest ample opportunities for interventions to improve brain health, even in populations with high levels of inflammation."

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