The Tsimane: What Can these Cardiac Supermen Teach Us About Heart Health?

By: Chani Grossman  |  April 3, 2017

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It sometimes seems like heart disease is an inescapable part of human existence—even autopsied Egyptian mummies have been found with the high levels of atherosclerosis, or hardening of the arteries, that are closely linked with heart disease. We tend therefore to view atherosclerosis as a natural part of the aging process that comes along with greying and developing wrinkles. This attitude mitigates our shock at disturbing heart-health statistics such as those revealed by the Multi-Ethnic Study of Atherosclerosis, a US-based survey of almost 7,000 people aged 45-84, which reported that only 14% of those surveyed did not have a risk of heart disease and 40-50% had moderate to high risk of heart disease. But because high rates of heart disease in the middle aged or elderly seem normal and unavoidable, we shrug this off.

However, scientists are starting to question that assumption. They have discovered the Tsimane, a remote Bolivian tribe whose heart disease rates are astonishingly low. In contrast with Americans, who have only a 14% chance of not developing heart disease, only 16% of the Tsimane in the same age bracket had any risk of heart disease at all, according to a long-term study written up in The Lancet. Even more shockingly, this tendency held up even until age 80 and beyond—when only 65% of Tsimane displayed atherosclerosis and heart disease. The likelihood for Tsimane men and women to develop heart disease is identical. In contrast, American men have five times the chance of developing heart disease that American women do.

The American diet and lifestyle are often bemoaned and even joked about for being natural causes of high cholesterol, high rates of atherosclerosis and disproportionate occurrences of other lifestyle-related health problems. The 36% rate of obesity calculated by the National Institute of Health, for example, is often correlated with American fast-food culture and sedentary lifestyle, which has only been furthered by technology. As such, researchers are often look to remote cultures and past civilizations to see if their health was better than ours today. In the Lancet article, researchers claim that the Tsimane have the healthiest hearts of any civilization or group yet discovered. Examination of certain beneficial characteristics that Americans tend to lack— like low levels of LDL, a harmful cholesterol, low levels of glucose, not smoking, and high rates of exercise—shows that the Tsimane display all of these traits. In fact, as the long-term study progressed and the Tsimane were exposed to additional modern technology and pre-prepared food, their risks of heart disease increased. In light of this, it is easy to suggest that fewer modern conveniences cause certain beneficial lifestyle aspects associated with excellent health.

However, Michael Gurven, one of the scientists associated with the long-term study and the Lancet paper, notes in an article published on the University of California’s website that there are two anomalies in the health data of the Tsimane which don’t support the position that they are “cardiac Supermen.” One is that, while their LDL is very low, their HDL, or beneficial cholesterol, is also dangerously low. This itself can be a contributing factor to heart disease. The other anomaly that Gurven noted is that the Tsimane can have perilously high rates of inflammation, which is often correlated with atherosclerosis. He also pointed out that the Tsimane have a 21% rate of obesity. This is quite good in contemporary contexts, but still high considering the low rate of heart disease. Gurven argues that the answer must lie in something more complex.

In another paper published in Evolution, Medicine and Public Health, Gurven and several colleagues suggest another conclusion, in which the Tsimane and other remote tribes owe their excellent cardiac health as well as their reduced likelihood of type 2 diabetes to a disconcerting cause: helminths, or parasitic intestinal worms. These researchers believe that these parasitic worms burn calories, consume lipids, promote insulin sensitivity and help regulate inflammation, thereby preventing heart disease and diabetes in the populations which host them. The researchers are still unsure of the exact mechanism by which inflammation fits in—how the high levels of inflammation don’t have an adverse medical effect—but they are working on several hypotheses and recognize the need to take many disparate and seemingly crazy factors into account.

Does this mean we should swallow parasites in an attempt to cure our tendencies for heart disease and diabetes? At this stage, no—and the more typical practices in which the Tsimane engage, such as high-plant diets and regular moderately strenuous activity, are already enough to contribute to our improved health. There is no need to go to unusual hypotheses in order to avoid taking into account inconvenient truths about the ways that our lifestyles negatively impact our health. But the discussion of the Tsimane is still a fascinating question which could bear fruit in the future. Who knows—maybe we’ll all be swallowing helminths one of these days.