A recent study finds that the brains of indigenous Amazonians age 70% slower than that of Europeans or Americans.
The Tsimane are a group of indigenous Amazonians that live in an isolated area of the Bolivian. The community of approximately 16,000 individuals depend on farming, hunting, and fishing for their survival. Their limited access to modern healthcare has resulted in a high burden of disease and rates of inflammation. However, in 2017, a Lancet study revealed them to have the lowest prevalence of cardiovascular disease (CDC) compared to those in the Western world. Despite high inflammation, they had fewer CVD risk factors, such as obesity, diabetes, and hypertension.
Now, a team of international researchers has found that along with a healthy heart, the indigenous Amazonians also have healthy brains.
This study demonstrates that the Tsimane stand out not only in terms of heart health but brain health as well. The findings suggest ample opportunities for interventions to improve brain health, even in populations with high levels of inflammationProfessor Hillard Kaplan, study author
The team recruited a total of 746 members of the Tsimane, aged between 40 to 94 years. They then travelled to the nearby village of Trinidad, Bolivia for computed tomography (CT) scans. The scans helped calculate brain volumes and their association with age. The results were compared to those living in developed countries across the US and Europe. The findings of the study are available in The Journal of Gerontology, Series A: Biological Sciences and Medical Sciences.
“A Baseline for Healthy Brain Aging“
Brain atrophy puts one at risk of cognitive decline and dementia. CVD factors such as hypertension and diabetes can increase the risk of cognitive impairment by causing a faster loss of brain volume. Similarly, a high inflammation and disease burden can also cause greater brain atrophy.
However, in the case of the Tsimane despite their high inflammation, their brain volumes decreased 70% slower than the Western population’s. Thus, revealing that this indigenous group faces less brain atrophy as they age.
The Tsimane have provided us with an amazing natural experiment on the potentially detrimental effects of modern lifestyles on our healthProfessor Andrei Irimia, study author
Although the Tsimane don’t have access to basic health care, they live an active lifestyle and consume a high-fibre diet full of fruits and vegetables. Unlike the Western world where people have more of a sedentary lifestyle and a diet rich in sugar and fats. Study authors believe that since the inflammation in the Tsimane is due to infectious diseases, it does not contribute to brain ageing to such an extent. Whereas, in developed countries, inflammation is caused more by metabolic causes or obesity. Thus, implying that an unhealthy lifestyle is a cause for the development of cognitive decline and dementia in people.
The findings of the study highlight the possible interventions for improving brain health in people with high levels of inflammation.
Irimia, Andrei, et al. “The Indigenous South American Tsimane Exhibit Relatively Modest Decrease in Brain Volume with Age despite High Systemic Inflammation.” The Journals of Gerontology: Series A, 2021, doi:10.1093/gerona/glab138.