Indigenous communities provide clues to healthy brain aging

Due to industrialization, humans are now enjoying greater access to food, less physical toil, and better access to quality health care services than ever before. However, since many people are currently eating more and exercising less, sedentary lifestyles and obesity have led to smaller brain volumes and faster cognitive decline in a significant part of the western population.

Now, a team of researchers led by the University of Southern California (USC) has discovered that some of the lowest rates of heart and brain disease ever reported are found among Indigenous communities from the tropical forests of lowland Bolivia, suggesting that there are optimal levels of food consumption and exercise that can maximize healthy brain aging and decrease the risk of disease. 

The scientists enrolled 1,165 participants from two Indigenous societies – the Tsimané and Mosetén – and measured their brain volume by age, along with their body mass index, blood pressure, cholesterol, and other markers of energy and overall health. 

The analysis revealed that the Tsimané and Mosetén experienced better cardiovascular health and less brain atrophy than U.S. and European populations, and were thus less likely to develop heart disease or neurodegenerative conditions such as dementia or Alzheimer’s.

“The lives of our pre-industrial ancestors were punctured by limited food availability,” said study senior author Andrei Irimia, an assistant professor of Gerontology, Biomedical Engineering, and Neuroscience at USC. “Humans historically spent a lot of time exercising out of necessity to find food, and their brain aging profiles reflected this lifestyle.”

Since the Mosetén are more exposed to modern technology, medicine, infrastructure, and education than the Tsimané, they served as an important intermediary population, allowing researchers to compare a variety of lifestyle and health care factors. While both communities showed better health than industrialized populations, the Mosetén fared a bit worse than the Tsimané, reinforcing the hypothesis that industrialized or semi-industrialized societies fail to achieve a healthy balance between daily exertion and food consumption.

“During our evolutionary past, more food and less calories spent in getting it resulted in improved health, well-being, and ultimately higher reproductive success or Darwinian fitness,” said study lead author Hillard Kaplan, a professor of Health Economics and Anthropology at Chapman University. “This evolutionary history selected for psychological and physiological traits that made us desirous of extra food and less physical work, and with industrialization, those traits lead us to overshoot the mark.”

According to Professor Irimia, the best way to improve brain health and reduce the risk of disease is to have neither too little nor too much food and nutrients, along with a vigorous amount of exercise. “This ideal set of conditions for disease prevention prompts us to consider whether our industrialized lifestyles increase our risk of disease,” he concluded.

The study is published in the journal Proceedings of the National Academy of Sciences.

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By Andrei Ionescu, Earth.com Staff Writer

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