Bolivian Tsimane People Have World’s Healthiest Arteries, Study Says
According to a new study published in The Lancet , the Tsimane (pronounced chee-MAH-nay) — an indigenous people of lowland Bolivia — have the lowest reported levels of coronary artery disease of any population recorded to date, with coronary atherosclerosis being five times less common than in the United States.
Tsimane village from the water. Image credit: Hillard Kaplan et al .
“The lifestyle of the Tsimane people 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,” said lead author Professor Hillard Kaplan, from the University of New Mexico.
“The loss of subsistence diets and lifestyles could be classed as a new risk factor for vascular ageing and we believe that components of this way of life could benefit contemporary sedentary populations.”
Although the Tsimane lifestyle is very different from that of contemporary society, certain elements of it are transferable and could help to reduce risk of heart disease.
While industrial populations are sedentary for more than half of their waking hours (54%), the Tsimane spend only 10% of their daytime being inactive.
They live a subsistence lifestyle that involves hunting, gathering, fishing and farming, where men spend an average of 6-7 hours of their day being physically active and women spend 4-6 hours.
Their diet is largely carbohydrate-based (72%) and includes non-processed carbohydrates which are high in fiber such as rice, plantain, manioc, corn, nuts and fruits. Protein constitutes 14% of their diet and comes from animal meat.
The diet is very low in fat with fat compromising only 14% of the diet – equivalent to an estimated 38 grams of fat each day, including 11g saturated fat and no trans fats.
In addition, smoking was rare in the population.
In the observational study, Prof. Kaplan and co-authors visited 85 Tsimane villages between 2014 and 2015.
They measured the participants’ risk of heart disease by taking CT scans of the hearts of 705 adults (aged 40-94 years old) to measure the extent of hardening of the coronary arteries, as well as measuring weight, age, heart rate, blood pressure, cholesterol, blood glucose and inflammation.
Based on their CT scan, almost nine in 10 of the Tsimane people had no risk of heart disease, 13% had low risk and only 3% had moderate or high risk.
These findings also continued into old age, where almost two-thirds of those aged over 75 years old had almost no risk and 8% had moderate or high risk.
These results are the lowest reported levels of vascular ageing of any population recorded to date.
By comparison, a US study of 6,814 people (aged 45 to 84) found that only 14% of Americans had a CT scan that suggested no risk of heart disease and half (50%) had a moderate or high risk.
In the Tsimane population, heart rate, blood pressure, cholesterol, and blood glucose were also low, potentially as a result of their lifestyle.
The authors also note that the low risk of coronary atherosclerosis was identified despite there being elevated levels of inflammation in half of the Tsimane population (51%).
“Conventional thinking is that inflammation increases the risk of heart disease. However, the inflammation common to the Tsimane was not associated with increased risk of heart disease, and may instead be the result of high rates of infections,” said co-author Professor Randall Thompson, from Saint Luke’s Mid America Heart Institute.
Because this study is observational it cannot confirm how the Tsimane population is protected from vascular ageing, or which part of their lifestyle (diet, physical activity or smoking) is most protective.
The researchers suggest it is more likely to be a result of their lifestyle than genetics, because of a gradual increase in cholesterol levels coinciding with a rapidly changing lifestyle.