Heart attacks and strokes are virtually unknown among the Tsimane people of the Bolivian rainforest. What can we learn from this?
The Tsimane people of the Bolivian Amazon have the world’s healthiest hearts. A study published earlier this month in The Lancet says that heart attacks and strokes are virtually unknown among this population that follows a pre-industrialized lifestyle. Heart rate, blood pressure, cholesterol, and blood glucose are also impressively low. When calcium plaque buildup is used as a measure of arterial age, Tsimane arteries look thirty years younger than ours. In other words, an 80-year-old Tsimane man has the heart of a 50-year-old American.
While much of the Western world struggles with sickly hearts and their consequences, this research is particularly relevant. It could hold valuable clues to improving the health of people in industrial nations, where more than 50 percent of the population is at moderate to high risk of heart disease.Says senior anthropology author Professor Hillard Kaplan of the University of New Mexico:
“Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied. Their lifestyle suggests that a diet low in saturated fats and high in non-processed fiber-rich carbohydrates, along with wild game and fish, not smoking and being active throughout the day could help prevent hardening in the arteries of the heart.”
How do the Tsimane live?
There are two big differences that set their lifestyle apart from ours – one being exercise and the other diet. They are very physically active, with only 10 percent of their day spent sitting (compared to 54 percent of industrial populations). They trek through the forest on hunts that last eight hours on average, covering 10 miles (16 kilometres) on foot. They hunt with bows, forage for berries, clear farmland with scythes and axes, and fish on the rivers.
Nearly three-quarters of their diet is high-fiber carbohydrates, such as manioc, corn, rice, nuts, and fruit, while animal proteins, like howler or capuchin monkeys, wild pig, and raccoons, make up only 14 percent. The other 14 percent is fat, an estimated 38 grams per day, which is low compared to American populations that consume around 33 percent fat. Smoking is rare.
The researchers visited 85 Tsimane villages between 2014 and 2015 to observe the lifestyle; and 705 villagers, aged 40 and over, traveled two days to a clinic to have their arteries examined by a CT scan, in order to “gauge how much plaque was clogging the arteries around the heart.” The Washington Post quotes Matthew Budoff, a UCLA cardiologist and expert in coronary calcium:
“These calcium scores ‘are the best predictors of heart disease. It’s a direct measure of atherosclerosis. It’s literally measuring the disease in the artery.’”
While the researchers are not sure which is more important – diet or physical activity level – they suspect that lifestyle plays a bigger role than genetics in determining heart disease. As some Tsimane come into closer contact with industrial societies and adopt new habits, their arterial health has deteriorated and cholesterol levels have risen. Dr. Trumble said in The Guardian:
“Over the last five years, new roads and the introduction of motorized canoes have dramatically increased access to the nearby market town to buy sugar and cooking oil. This is ushering in major economic and nutritional changes for the Tsimané people.”
One anthropologist, Benjamin Trumble from Arizona State University, spent time living with the Tsimane over a two-year research period. He pointed out that, while many people assume Indigenous subsistence life must be “nasty, brutish, and short,” it is not. The Tsimane live to around 70 years of age and live in communities of 60 to 200 members.
It is unfortunate to think of Tsimane health worsening, as it’s unlikely industrial nations will adopt Tsimane habits. The lack of clean water, the prevalence of parasitic worms, and the icky sour flavor of monkey meat are likely to turn away most converts. That being said, there are important lessons in this research – primarily, to keep one’s diet low in sugar, to reduce cholesterol and blood pressure, to exercise regularly, and not to smoke.