It’s a sad fact of life that as we age, our health begins to decline. Our brains get slower, our hearts get weaker, our bodies can’t do what they used to. But it doesn’t have to be the way. A new study of the Tsimane, a group of Indigenous people in the Bolivian Amazon, finds that they have impressive brain health into old age. Their lifestyle is probably to thank for it.
The Tsimane are a group of about 16,000 Indigenous people who live in remote villages in the Bolivian jungle. They survive off of hunting, gathering, fishing, and farming. This means their diet is high in fiber and includes plenty of vegetables, fish, and lean meats. They’re also highly physically active.
Americans and Europeans, on the other hand, follow a diet high in sugar and saturated fats. They’re highly sedentary; the average US adult sits for six-and-a-half hours per day.
Possibly because of the lifestyle difference, the Tsimane have far healthier brains into old age. Over time, the brain tends to atrophy and lose volume, which is linked to cognitive impairment, functional decline, and dementia. But brain scans show that the Tsimane have 70 percent less of a brain volume gap between middle and old age compared to Westerners, according to a study of 746 Tsimane adults ranging from ages 40 to 94. This suggests that the Tsimane’s brains atrophy less from middle to old age.
“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 study author Hillard Kaplan, a professor of health economics and anthropology at Chapman University, who has studied the Tsimane for almost two decades. “The Tsimane can serve as a baseline for healthy brain aging.”
Brains aren’t the only health feat of the Tsimane. They have healthy hearts too — the healthiest of any population known to science, according to a 2017 study. The Tsimane have the lowest prevalence of coronary artery disease and have few risk factors for cardiovascular disease, such as high blood pressure, diabetes, being overweight or obese, and more.
“The Tsimane have provided us with an amazing natural experiment on the potentially detrimental effects of modern lifestyles on our health,” said study author Andrei Irimia, a professor of gerontology, neuroscience and biomedical engineering at the University of Southern California. “These findings suggest that brain atrophy may be slowed substantially by the same lifestyle factors associated with very low risk of heart disease.”
The Tsimane have healthy hearts and brains despite their low level of access to healthcare and high levels of inflammation, the latter of which is linked to brain atrophy in Americans and Europeans. However, Westerners’ inflammation is associated with obesity and metabolic causes, whereas inflammation in the Tsimane comes from infectious diseases, which are the most common cause of death among the group. So there may be more underlying the connection between inflammation and conditions such as dementia than researchers originally thought.
What this means for people in the U.S. and Europe isn’t entirely clear; more studies are needed to pinpoint the exact reason for the Tsimane’s extraordinary brain and heart health. In the meantime, it won’t hurt to cut down on saturated fats, eat more fiber, and try to sit less during the day.