Hunter-gatherer lifestyle could fight off ageing
Lifestyle and environment may be more influential on how we age than inflammation, new research says. Activity, simple foods and exposure to germs may be the keys to fight “inflammaging”.
A study has cast doubt on a widely-accepted belief that chronic inflammation is an inevitable part of ageing, raising questions about how lifestyle and environment shape our health in later life.
Scientists have long flagged “inflammaging” – persistent, low-level inflammation that increases as a person grows older – as a key driver of age-related illnesses such as heart disease, dementia and diabetes.
However, research published in Nature Ageing suggests that it is not inevitable but driven by modern lifestyles.
The researchers examined blood samples from more than 2800 people aged between 18 and 95 from four locations: city dwellers in Italy and Singapore, and two indigenous groups – the Tsimane of the Bolivian Amazon and the Orang Asli in Malaysia. In the Italian and Singaporean groups, the expected pattern emerged: molecules that signal inflammation increased steadily with age and were strongly associated with chronic illnesses. However, among the Tsimane and Orang Asli, this pattern was absent. Inflammatory markers did not rise with age and they were not strongly linked to the same cluster of diseases.
“Inflammaging, as measured in this manner in these cohorts, thus appears to be largely a by-product of industrialised lifestyles,” the researchers, who were led by Maximilien Franck, of the University of Sherbrooke in Canada, wrote.
The semi-nomadic Tsimane follow a subsistence lifestyle, combining slash-and-burn agriculture with hunting, fishing and gathering. Their diet is high in fibre and unprocessed foods and previous research has suggested that less than 10 per cent of their daylight hours are spent on sedentary activities, compared with roughly 50 per cent, on average, for city populations.
The Orang Asli are made up of subgroups whose lifestyles differ. However, many combine farming with foraging and hunting for wild game.
Despite high levels of infection related to inflammation, particularly among the Tsimane, both populations had low rates of conditions such as heart disease, diabetes and dementia. The findings suggest that inflammaging may be the result of modern lifestyles, including calorie-dense diets, sedentary behaviour and possibly a reduced exposure to germs.
In traditional environments, where people are more active and frequently exposed to pathogens, the immune system may operate differently and inflammation may not necessarily lead to chronic disease. “These findings challenge the assumption that human physiological processes are universal and can be extrapolated from one population to others,” the researchers said.
That a person’s environment, lifestyle and diet can affect inflammation levels was already known. Another recent study involved asking participants to switch from processed western-style foods to a diet typical of Tanzania, rich in vegetables, legumes, ancient grains and fermented foods. After two weeks, tests suggested strikingly positive effects. In particular, it dampened inflammation. Proteins in the blood linked to a cluster of conditions, including heart attacks, strokes and insulin resistance, also fell.
Another group of participants who switched from traditional African foods to a western-style diet experienced an increase in the markers of inflammation.
The Times
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