Communities where people age more slowly than the rest of the world

As Martina Canchi Nate walked through the Bolivian jungle, red butterflies fluttering around her, we had to ask her to stop – our group couldn’t keep up.

Her ID card said she was 84 years old, but within 10 minutes she had dug up three yucca plants to remove the tubers from their roots, and with just two strokes of her knife she had chopped down a banana tree.

She carried a large bunch of fruit on her back and started walking home from the chaco – the land where she grew cassava, corn, bananas and rice.

Martina is one of 16,000 Tsimane (pronounced “chee-may-nay”) people – a semi-nomadic indigenous community living deep in the Amazon rainforest, 600km (375 miles) north of Bolivia’s largest city, La Paz.

Her vitality is not unusual for a Tsimane person her age. Scientists have concluded that this group has the healthiest arteries ever studied, and their brains age more slowly than those of people in North America, Europe and elsewhere.

The Tsimane are a rare group. They are one of the last groups on the planet to live a completely subsistence lifestyle of hunting, foraging, and farming. They are also large enough to provide a significant scientific sample, and researchers led by anthropologist Hillard Kaplan of the University of New Mexico have studied them for two decades.

The Tsimane people have always been active – hunting animals, farming and thatching.

Less than 10% of their daytime is spent in sedentary activities, compared to 54% in industrial populations. For example, an average hunt lasts more than eight hours and covers 18km.

They live on the Maniqui River, about 100km by boat from the nearest town, and have little access to processed foods, alcohol and tobacco.

Researchers found that only 14% of the calories they ate came from fat, compared with 34% in the United States. Their foods were high in fiber, and 72% of their calories came from carbohydrates, compared with 52% in the United States.

Protein came from the animals they hunted, such as birds, monkeys, and fish. When it came to cooking, traditionally there was no frying.

The initial work by Professor Kaplan and his colleague, Michael Gurven of the University of California, Santa Barbara, was anthropological. But they found that the older Tsimanes did not exhibit typical signs of old age, such as high blood pressure, diabetes or heart problems.

Then a study published in 2013 caught their attention. A team led by American cardiologist Randall C Thompson used CT scans to examine 137 mummies from ancient Egyptian, Inca and Unangan civilizations.

As people age, a buildup of fat, cholesterol and other substances can cause arteries to thicken or harden, leading to atherosclerosis. They found signs of this in 47 mummies, challenging assumptions that it is caused by modern lifestyles.

The two research teams collaborated and conducted CT scans on 705 Tsimane people over the age of 40, looking for coronary artery calcium (CAC) – a sign of blocked blood vessels and risk of heart attack.

Their research, first published in the journal TLancet 2017found that 65% of Tsimane people over the age of 75 had no CAC. By comparison, most Americans in that age group (80%) had signs of it.

As Kaplan puts it: “The arteries of a 75-year-old Tsimane person are more like those of a 50-year-old American.”

Phase two, announced in 2023 In the journal Proceedings of the National Academy of Sciences, older Tsimane people were found to have up to 70% less brain shrinkage than people of the same age in industrialized countries such as Britain, Japan and the United States.

“We found no cases of Alzheimer’s in the entire adult population – that’s remarkable,” said Bolivian doctor Daniel Eid Rodríguez, medical coordinator for the researchers.

However, calculating the age of the Tsimane is not an exact science. Some people have difficulty counting because they are not well educated in numbers. They told us they are guided by records of Christian missions in the area or by how long they have known each other. Scientists base their calculations on the ages of a person’s children.

According to their records, Hilda is 81 years old, but she said her family recently killed a pig to celebrate “her 100th birthday or something.”

Juan, who said he was 78, took us hunting. He had dark hair, bright eyes and strong hands. We watched as he stalked a small taitetú—a hairy wild boar—that had slipped through the foliage and escaped.

He admits that he feels old: “The hardest thing now is my body. I don’t walk far anymore… two days at most.”

Martina agreed. Tsimane women are famous for weaving roofs from jatata, a tree that grows deep in the forest. To find it, Martina had to walk three hours there and three hours back, carrying branches on her back.

“I do it once or twice a month, although it’s harder for me now,” she said.

However, many Tsimane never reach old age. When the study began, their average life expectancy was just 45 years – now it has risen to 50.

At the clinic where the scan takes place, Dr. Eid asks the elderly woman about her family as she prepares to be examined.

Counting on her fingers, one woman sadly said she had six children, five of whom had died. Another said she had twelve, four of whom had died – another said she had nine children who were still alive, but three others had died.

“People who live to be 80 are those who survived childhoods filled with illness and infection,” says Dr. Eid.

The researchers believe that all Tsimane people experience some type of parasitic or worm infection throughout their lives. They also found high levels of pathogens and inflammation, suggesting that the Tsimane bodies are constantly fighting off infections.

This led them to wonder whether these early infections were another factor – beyond diet and exercise – influencing the health of older Tsimane people.

However, the community’s lifestyle is changing.

Juan said he had not been able to hunt an animal big enough for months. A series of wildfires in late 2023 destroyed nearly two million hectares of bush and forest.

“The fire has driven the animals away,” he said.

He has now started raising cattle and showed us four beef cattle that he hopes will provide protein for the family by the end of the year.

Dr Eid said the use of outboard motor boats – known as peque-peques – had also brought about change. It provided easier access to markets, giving the Tsimane access to food items such as sugar, flour and oil.

And he points out that means they row less than before – “one of the most physically demanding activities”.

Twenty years ago, diabetes was virtually unheard of. Now it is starting to appear, while cholesterol levels are also starting to rise in younger populations, researchers have found.

“Any small change in their habits will impact these health indicators,” says Dr. Eid.

And the researchers themselves have had an impact over the 20 years they’ve been involved – arranging better access to health care for the Tsimane, from cataract surgery to treatment for broken bones and snake bites.

But for Hilda, old age is not something too serious. “I’m not afraid of dying,” she told us, laughing, “because they will bury me and I will stay there… very quiet.”