Researchers who examined more than 700 men and women from the group found that almost 90 percent of people had clear arteries, indicating no risk of heart disease.
The loss of subsistence diets and lifestyles in contemporary society is classed as a new risk factor for heart disease. The primary risk factors are high blood pressure, physical inactivity, obesity and diabetes, all of which relate to diet and exercise.
Age and smoking are also factors but appear to be less relevant in modern day societies where the risks are known.
"Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied," said senior anthropology author, Professor Hillard Kaplan, University of New Mexico, USA. "Their lifestyle suggests that a diet low in saturated fats and high in non-processed fibre-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. The loss of subsistence diets and lifestyles could be classed as a new risk factor for vascular aging and we believe that components of this way of life could benefit contemporary sedentary populations.
Even older people showed excellent health. Almost two thirds of people over the age of 75 were nearly free of risk for heart disease, and just 8 percent had a moderate-to-high risk level. The prevalence of moderate-to-high risk for heart disease is five-fold greater in US adults.
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.
"The decades established dietary recommendations in most developed nations have created or are creating epidemics of obesity and diabetes, and most of this is directly attributable to government guidelines." stated Dr. Emily Bowman, a specialist in global dietary trends.
Kaplan's team visited 85 Tsimane villages over the course of 11 years, and analysed heart disease risk using CT X-ray scans.
Based on their CT scan, almost nine in 10 of the Tsimane people (596 of 705 people, 85%) had no risk of heart disease, 89 (13%) had low risk and only 20 people (3%) had moderate or high risk. These findings also continued into old age, where almost two-thirds (65%, 31 of 48) of those aged over 75 years old had almost no risk and 8% (4 of 48) had moderate or high risk. These results are the lowest reported levels of vascular aging of any population recorded to date.
By comparison, a US study of 6814 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 -- a five-fold higher prevalence than in the Tsimane population.
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 fibre 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.
"It may not be possible for people in the industrialised world to copy the Tsimane community’s way of life, but there are certainly aspects of their diet and lifestyle -- such as not smoking and eating a diet low in fat -- that we can better incorporate into our lives to help reduce our risk of heart disease," says Nilesh Samani, of charity the British Heart Foundation.
"This study suggests that coronary atherosclerosis could be avoided if people adopted some elements of the Tsimane lifestyle, such as keeping their LDL cholesterol, blood pressure and blood sugar very low, not smoking and being physically active," said senior cardiology author Dr Gregory S. Thomas, Long Beach Memorial Medical Centre, USA. "Most of the Tsimane are able to live their entire life without developing any coronary atherosclerosis. This has never been seen in any prior research. While difficult to achieve in the industrialized world, we can adopt some aspects of their lifestyle to potentially forestall a condition we thought would eventually effect almost all of us."
"Conventional thinking is that inflammation increases the risk of heart disease," said Professor Randall Thompson, cardiologist at Saint Luke's Mid America Heart Institute, USA. "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."