The heart of the matter

The Tsimane or Chimane people are an isolated, indigenous tribe who maintain their tough, subsistence traditions in a remote area of Bolivia’s Amazonian lowlands, faithfully foraging and farming in small, rural settlements along the Maniqui River, like their ancient ancestors. Self-sufficient as their relatives in Guyana, the Amerindians, once were, the sensational Tsimane recently made international headlines for having the world’s healthiest arteries.

Researchers who have closely studied the close-knit group for years reveal that heart attacks and strokes are nearly unknown among the busy villagers thanks to a high natural carbohydrate and low protein diet, and an incredibly active lifestyle. Living on mainly cassava, corn, plantain, rice, wild fruits, nuts, game and fish, the Tsimane spend most of their difficult days simply working hard and on the move – hunting, fishing and cultivating their crops. It is estimated that they are inactive for only about ten per cent of their time. Dwelling in thatched huts with no electricity, running water or sanitation, they spend hours tracking the occasional deer and tapir with their bows and arrows, catching fish with hallucinogenic vines, and clearing the lush rainforests through the slash and burn method.

According to compelling research presented at an American College of Cardiology conference last month, “Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied,” disclosed Professor Hillard Kaplan, the lead senior anthropology author from the University of New Mexico. They are at least five times less likely than people in the United States to develop coronary atherosclerosis, which refers to the thickening and narrowing of arteries caused by the build-up of plaque consisting of substances like cholesterol, calcium and fibrin, a clotting material.

“Their (pre-industrial) 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,” Kaplan said.

More than 700 people aged 40-90 were involved in the decade-long study, which was funded by the U.S National Institutes on Aging and of Health. Almost nine out of 10 of the respondents had clear arteries, indicating no risk of heart disease, with the vessels of an 80-year-old elder resembling that of an American in their mid-50s. Tsimane (pronounced chee-mah-nay) men spend an average of six to seven hours a day engaged in constant physical activity, while women are busy for around four to six hours.

Published in “The Lancet” the venerable, independent, British medical journal, the findings reflect that almost two thirds of the Tsimane people aged over 75 were in the clear and just eight per cent had a moderate-to-high risk. They eat a mere 14 per cent of protein and a similar amount of fat, with each person consuming roughly 38 grams of fat daily, of which just 11 grams is saturated fat.

While it is difficult to copy the Tsimane community’s entire way of life in the modern world, there are certainly several valuable lessons to be learnt, especially in Guyana and the Caribbean where rising heart attacks and cardiovascular ailments continue to alarm, being the leading cause of deaths from Non-Communicable Diseases (NCDs). Just this week, resident cardiologist, Dr Mahendra Carpen cited the almost full time occupancy of the recently established Cardiac Intensive Care Unit (CICU) at the Public Hospital Georgetown.

Stabroek News reported that he attributed this high rate to a combination of factors. “Some of it is definitely genetics but a lot of it has to do with people being unaware of their underlying risk factors for heart disease; too many of my patients are coming with heart attacks not knowing they were diabetic or have high blood pressure, and are still smoking,” he explained, stressing that smoking, a preventable habit is “particularly worse for women.” Poor diet and lifestyle choices are also to blame of course.

Individuals of South Asian descent, consisting half of Guyana’s population, tend to have little coronary arteries prompting ready blockages. “Their cholesterol particles tend to be smaller and are much more dangerous, so often times I don’t pay too much attention to the cholesterol number when the results come back from the lab because these patients are (already) at a higher risk, so we have to treat them with more caution,” Dr Carpen noted.

For instance, a key paper in the World Journal of Cardiology last year underscored that this category has a higher prevalence and an earlier-onset of coronary heart disease (CHD) compared to other ethnic groups, concluding that such people and their descendants carry a unique lipid profile which predisposes them to the condition and possible premature death. Dyslipidemia or the medical condition referring to an abnormal level of blood lipids, seems to be an important contributor to the high incidence of coronary atherosclerosis or plaque accumulation in the population segment. It is characterised by greater glucose intolerance, “elevated levels of triglycerides, low levels of high-density lipoprotein (HDL) cholesterol, elevated lipoprotein (a) levels, and a higher atherogenic (tending to promote the formation of fatty deposits in the arteries) particle burden despite comparable low-density lipoprotein cholesterol levels with other ethnic subgroups. HDL particles also appear to be smaller, dysfunctional, and pro-atherogenic in South Asians.”

Conventional factors such as hypertension, diabetes, abdominal obesity, metabolic syndrome, tobacco and alcohol use are clearly associated with risk, the article pointed out. Sedentary existence and dietary influences play a critical role too, with excess sugars and refined carbohydrates use remaining a major issue and constituting a considerable threat to future health and wellness.

Claiming the number 14 world ranking for coronary heart disease cases, Guyana is listed high, in the fourth spot for stroke, the third for diabetes and hypertension, respectively, and the first for prostate cancer cases, based on online data from Worldlifeexpectancy.com

In 2016, a major health workshop in Port-of-Spain warned that the regional response to the growing epidemic of CHD, stroke, diabetes and cancer needs to be intensified immediately, since the NCD burden is the worst in the Americas and overall CARICOM residents now have a lower life expectancy than their counterparts. In some member countries, up to 80 per cent of adults are overweight, obese or unaware they have high cholesterol, more than half have high blood pressure and quarter are diabetic with the prevalence of the disease being double the global number. Four out of every ten NCD deaths occur prematurely in those under 70 and can be averted. The Pan American Health Organization (PAHO) acknowledges the Caribbean has the highest death rates from heart disease and the top five countries for diabetes in the Americas

Onecaribbeanhealth.org estimates in excess of 85 per cent of adults in member states do not take in the minimum recommended levels of fruits and vegetables daily, and less than a third of schoolchildren aged 13-15 years get the basic amount of physical activity, even as their alcohol drinking tops 40 per cent in 11 out of 20 countries. Barbados, Jamaica, Trinidad and Tobago and Dominica are in the top 14 nations for global female obesity while West Indian men generally partake heavily in alcohol and tobacco.

The Tsimané population indulges occasionally in fermented drink but only during communal social events bringing together families and villages when cassava beer similar to Guyana’s “paiwari” and “cassiri” are brewed. Traditionally animists who believe in supernatural creatures that control their fortunes, the Tsimane have largely remained cut off from modern society since rejecting the religious advances of Jesuit missionaries in the late 17th century.

Indicating that genetic risk may be far less important than lifestyle and environment, the landmark Tsimane analysis identifies the tribe’s low heart rates, blood pressure, cholesterol, and blood glucose, and an intriguing anomaly of raised inflammation markers that are not associated with the usual accelerated heart disease, but may instead be the result of high infection ratios. Tsimane blood tissue exhibits slower intrinsic epigenetic aging than that of other populations which may explain this paradox. Senior members show scant evidence of chronic diseases common elsewhere, like diabetes, atherosclerosis, asthma, and autoimmune disorders since intense physical activity is maintained well into late adulthood.

Despite their rugged lives, Tsimane men have a third less testosterone than Western men, but theirs do not decline with age, meaning they rarely suffer from obesity and related conditions. Tsimane women’s breast milk is also noticeably higher in omega-3 fatty acids.

Yet ominous signs loom of impending change and doom. “Over the last five years, new roads and the introduction of motorised canoes have dramatically increased access to the nearby market town to buy sugar and cooking oil,” said Dr Ben Trumble, of Arizona State University. “This is ushering in major economic and nutritional changes for the Tsimané people,” he cautioned, pointing out that the few who are adopting modern practices with outside exposure already have higher cholesterol levels than their counterparts who stick to village foods and long-established customs. As Dr Kaplan bluntly puts it, the loss of subsistence diets and supporting physically demanding lifestyles can be classed as a new risk factor for vascular aging.

In other words, if these outside excursions and bad habits intensify, the Tsimane will eventually become, sadly, as sick, fat and lazy as the rest of the Caribbean and the Americas, which would be literally heart-breaking.

ID cites a BBC news story on the average Tsimané mother of nine with a fascinating survey showing infection of the parasitic roundworm “Ascaris lumbricoides” believed to have suppressed their immune system making it easier to become pregnant, leading to two extra kids and possible “novel fertility enhancing drugs.”

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