Is modern life raising our blood pressure?

The common consensus that higher blood pressure is an inevitable consequence of aging has been upended by a newly published study about two isolated Amazon tribes.

According to the researchers, hypertension may actually be a result of certain aspects of Western lifestyles, “such as high levels of salt in the diet, lack of exercise and heavy drinking”, The Guardian reports. As the newspaper notes, high blood pressure is a key risk factor for cardiovascular disease.

The new research focused on two remote tribes living around the border of Brazil and Venezuela: the Yanomami and the Yekwana.

The Yanomami tribe “has proved particularly compelling to scientific researchers as several decades of study has revealed they have significantly low blood pressure levels, which do not seem to rise as they age”, says wildlife magazine New Atlas. The nearby Yekwana people are also fairly isolated but get regular deliveries of Western food and medicine via a local airstrip.

The study, published in the journal Jama Cardiology, looked at 72 Yanomami and 83 Yekwana people aged between one and 60.

Although ”the two groups were similar in other respects, average blood pressure among the Yanomami was 95/63, whereas in the Yekwana it was 104/66”, reports The Washington Post.

By the age of 60, blood pressure among the Yanomami remained unchanged, while the Yekwana average had risen to 114/73.

Study author, Noel T. Mueller, an assistant professor of epidemiology at Baltimore-based university Johns Hopkins, told the Post that this difference in blood pressure levels was found even in children. By the age of ten, Yekwana children had significantly higher blood pressure, with the divergence increasing with age.

“[That] to us indicates that interventions to prevent the rise in blood pressure and high blood pressure need to start early in life, where we can still have the opportunity to modify some of the exposures that might lead to high blood pressure,” Mueller said.

He added that while it may not be feasible to follow a Yanomami diet, just cutting salt intake in half could prevent an estimated 15 million cases of hypertension in the US alone.

“That blood pressure rises over age is probably not a natural phenomenon, but a cumulative effect of exposure to the Western diet,” he said. “Following a healthful diet low in processed food and salt can help reduce the risk for hypertension.”

However, some scientists have cast doubt over the findings, pointing to the small scale of the study and the lack of information about the tribes’ genetic make-up.

“It is unclear whether these factors fully explain the results, which may also be partly due to genetic factors,” said Dr James Sheppard, an expert in hypertension at Oxford University who was not involved in the study.