Rainforest regime could be key to a healthy heart

Henrietta Brewer
March 19, 2017

"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.

Coronary atherosclerosis (the hardening of the arteries) is five times less common in the Tsimane group than in America.

Heart rate, blood pressure, cholesterol, and blood glucose were also much lower, probably as a result of the tribe's lifestyle, according to the researchers. "They basically have the physiology of a 20-year-old".

They pointed to the community's low-fat, high-fibre diet and non-smoking, physically active lifestyle - factors which most scientists agree contribute to good health. Indeed, the study found that the heart of an 80-year-old Tsimané man was comparable to that of a 55-year-old man from the U.S.

"This study shows prevention really works", Thomas said. They scanned 705 people's hearts as well as mummified bodies. The Tsimane settlement of Anachere, in the Amazon rainforest, Bolivia.

Members of the tribe live in thatched huts in the Bolivian jungle.

Scientists examined hundreds of people from the group and found that nearly nine out of ten people have clear arteries. A score 100-400 is generally understood to mean mild coronary artery disease is highly likely.

By comparison, a study of 6,814 American people aged 45 to 84 found that only 14 per cent had a CT scan that suggested no risk of heart disease and half had a moderate or high risk - a five-fold higher prevalence than in the Tsimane.

His team visited 85 Tsimane villages over the course of 11 years, and analysed heart disease risk using CT X-ray scans.

Similar scans of almost 7,000 Americans in a previous study showed that only 14 per cent had no risk of heart disease, with half at moderate-to-high risk - a five-fold greater prevalence rate than that seen in the Tsimane population.

"This has never been seen in any prior research", senior study author Dr. Gregory Thomas, a cardiologist at the MemorialCare Heart & Vascular Institute in California, said in a statement.

On average, Tsimane women have nine children. In fact, the study showed that as Tsimane have been introduced to motorized canoes and some processed food, their cholesterol levels -although remarkably lower than other groups in the world- have increased too.

The Tsimane diet largely consists of plantain, rice, corn and fruits. "They mainly use cigarettes to burn these huge flies out of their skin, down there in the rainforest", he said. Higher amounts of calcium are associated with greater hardening of the arteries, and therefore a greater risk of heart disease, according to the study.

These results suggest that urbanization could be considered a risk factor for hardening of the arteries, as modern people leave behind lives of struggle for a more cushy existence, he said.

People who want to follow the example of the Tsimane would do well to consider US guidelines for physical exercise a starting point rather than a goal, said Dr. Douglas Jacoby, medical director of the Penn Medicine Center for Preventive Cardiology and Lipid Management in Philadelphia.

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