The Central American region where people live longest

Costa Rica is home to one of the five Blue Zones – regions of the world with populations that regularly live into healthy old age.

Blue Zones are regions of the world with populations that regularly live into healthy old age. There are just five Blue Zones on the entire planet, and research suggests that they are caused by a combination of factors, which range from diet and weather to religion. A magazine had commissioned me to find out why Costa Rica was home to one of these exceptional regions, so Dre, my then-girlfriend, and I flew there from California.

From the town of Puerto Viejo on Costa Rica’s Caribbean coast, we took a dug-out canoe up the Yorkin River, deep into the jungle that borders Panama. This is the homeland of Costa Rica’s indigenous Bribri people, whose remoteness kept their culture alive during successive European invasions.

The jungle is teeming with life, and the Bribri use that bounty for everything, ranging from camphor sap that repels mosquitoes to a plant that they chew for toothache. To my untrained eye, the Bribri gardens looked much like the rest of the jungle, with different species piled around each other and butterflies flitting between the branches. But that apparent chaos was deceptive.

“That’s because you are used to seeing farms of single crops,” said Albin, a local guide. “We don’t farm monocultures because the plants evolved to work in harmony: the legumes put nitrogen in the soil and banana trees put down potassium, so we don’t need artificial products or fertilisers.

“Each plant attracts different birds, so there’s hundreds of bird species here, whilst you might find only a dozen on a monoculture farm. Each species eats different insects, and there are also coral snakes and boas that kill rodents, so we don’t need pesticides or traps.”

“What about venomous snakes?” asked Dre.

“We do kill the fer-de-lance and bushmaster snakes,” Albin said, “Our gardens are right next to our villages, and those snakes can be really dangerous, especially to curious kids. Or curious tourists.”

The boat pulled into a small stone beach. Two young children – a brother and sister, watched over by their dad whilst he fished – giggled and screamed as they jumped into the river. They let the current carry them to an overhanging branch, which they used to haul themselves back to the riverbank before running upstream to repeat the whole process. The air was filled with the stony smell of river water and the warm sweetness of flowers and grasses. As we walked towards the village, Albin plucked fruits from the trees, most of which were completely unfamiliar to me.

“This is a water apple,” he said, before taking another, “This is monkey fruit. And that one is star fruit. They look different from the ones you’d find in a supermarket because they are less hybridised.”

He approached a tree that was about 20ft tall and had fruits sprouting directly from the trunk and branches. They were shaped like a ribbed rugby ball about the length of my hand-span, and mostly yellow or green.

“This is the cacao tree,” said Albin, tenderly touching the trunk, “Our people thought it was the most beautiful tree in paradise, and the seeds were used as currency.”

He plucked a yellow fruit, dappled with orange, and knocked it against the trunk. It split in half to reveal white flesh and perfectly tessellated seeds.