Scientists found that indigenous groups in the Amazon who farm, hunt, and gather had less brain atrophy and better cardiovascular health than those in industrialized countries.
Previous research investigating dementia rates among indigenous groups in the Bolivian Amazon found that only 1% of older Tsimané and Mosetén people had dementia. In comparison, estimates indicate that nearly 10% of U.S. adults ages 65 and older have dementia, and another 22% have mild cognitive impairment.
Tsimané people hunt, fish, and farm with hand tools. They also gather food from the forest. This lifestyle ensures they stay physically active throughout their lives. Although Mosetén people also engage in farming, they live closer to areas with medical facilities, schools, and access to clean water.
Researchers believe this healthier lifestyle plays a role in the reduced incidence of dementia among these groups.
To investigate this further, scientists examined the brain volumes and other health parameters in Tsimané and Mosetén adults. Their research was published on March 20 in the journal PNAS where scientists recruited 1,165 Tsimané and Mosetén adults aged 40 to 94 years and arranged transportation to a medical facility with CT scanning equipment.
The team measured the participant’s body mass index (BMI), total cholesterol, blood pressure, and other health biomarkers. The participants also underwent CT scans to measure their brain volume.
The results showed that the Tsimané and Mosetén participants had less brain shrinkage and better cardiovascular health than industrialized people in the United States and Europe.
The authors point out that the Mosetén people live closer to areas with more technology and infrastructure. And while the study found they had better health than people in the U.S. and Europe, their health was not as good as the Tsimané participants.
The research team suggests that the key to optimal brain health throughout the aging process might be finding a balance between exercise levels and food consumption.
In a news release, professor Hillard Kaplan, who has studied Tsimané people for nearly 20 years, says, "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."
Kaplan also notes, "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."
Andrei Irimia, co-corresponding author and assistant professor at USC Leonard Davis School of Gerontology, adds, "this ideal set of conditions for disease prevention prompts us to consider whether our industrialized lifestyles increase our risk of disease."
Still, a person doesn't have to spend all their time hunting, farming, and gathering to reap the same benefits found in the study. Instead, they can foster better brain and heart health as they age by ensuring they get enough exercise, eat a healthy diet, and maintain a healthy weight.
- University of Southern California. Study finds some of the world’s lowest dementia rates in Amazonian indigenous groups.
- Columbia University Irving Medical Center. One in 10 Older Americans Has Dementia.
- PNAS. Brain volume, energy balance, and cardiovascular health in two nonindustrial South American populations.
- USC News. For clues to healthy brain aging, look to the Bolivian Amazon.