For decades, scientists have accepted the idea that chronic inflammation increases steadily with age, a phenomenon commonly referred to as “inflammaging.” This persistent low-grade inflammation has been considered a universal hallmark of aging, intimately linked to the development of debilitating conditions such as cardiovascular disease, Alzheimer’s, and other neurodegenerative disorders. However, groundbreaking new research published in the Proceedings of the Royal Society B Biological Sciences is challenging this entrenched idea, presenting compelling evidence that inflammaging may not be as inevitable or widespread as previously believed.
This study, entitled “Inflammaging is minimal among forager-horticulturalists in the Bolivian Amazon,” conducted by a team led by Jacob Aronoff at Arizona State University, undertakes a meticulous investigation of inflammation patterns among two distinct Indigenous populations: the Tsimane and the Moseten. Both groups reside in the Bolivian Amazon and share close genetic ancestry, yet their lifestyles differ significantly due to differing degrees of modernization. The contrast between these communities offers a unique lens through which to explore how lifestyle, environment, and cultural change influence age-related inflammation.
The Tsimane, numbering over 17,000 individuals across approximately 90 villages, live a predominantly hunter-forager and horticulturalist lifestyle reminiscent of pre-industrial human societies. Their daily routines involve extensive physical activity, low-calorie, nutrient-dense diets, and close interaction with their natural environment. Prior investigations have highlighted exceptional cardiovascular health within this community, demonstrated by remarkably low rates of heart disease despite significant meat consumption. Additionally, the incidence of neurodegenerative diseases, including Alzheimer’s and dementia, is strikingly low among the Tsimane, raising important questions about the underlying biology that supports their longevity and neurological health.
In contrast, the Moseten have experienced profound cultural shifts over the last three centuries following contact with Jesuit missionaries, leading to partial integration of modern amenities such as running water, electricity, and indoor plumbing. Although genetically akin to the Tsimane, their relative modernization situates them in an intermediate socio-ecological niche, between the traditional ways of their ancestors and the industrialized lifestyle typical of Western societies. This divergence enables researchers to directly measure the effects of lifestyle modernization on immune system aging within a genetically homogenous framework.
Aronoff and colleagues measured a comprehensive panel of cytokines—proteins that regulate inflammation—in older adults from both populations using standardized laboratory technology. The results were striking: the Tsimane exhibited minimal increases in inflammatory markers with age, suggesting a substantial absence of classic inflammaging. Conversely, the Moseten showed a more pronounced age-related increase in inflammation, aligning more closely with patterns observed in industrialized societies. This data challenges the universality of inflammaging and implicates environmental and lifestyle factors as critical modulators of immune aging.
One intriguing hypothesis put forth by the researchers concerns the role of chronic parasitic and pathogen exposure. Unlike industrial societies, where deworming and sanitation have virtually eliminated parasitic infections, the Tsimane remain continually exposed to a range of parasites and pathogens throughout their lives. This persistent exposure may calibrate their immune systems to maintain a unique balance, potentially preventing the unchecked inflammation associated with aging. Such an immune conditioning might mitigate autoimmune pathologies and limit tissue damage often exacerbated by chronic inflammation.
Senior author Benjamin Trumble, who co-directs the Tsimane Health and Life History Project and has been working closely with this community for over two decades, underscores the importance of this perspective. He likens modern urban living to operating a machine well beyond its “manufacturer’s recommended warranty,” highlighting the mismatch between our evolutionary history and contemporary sedentary, industrial lifestyles. By studying populations maintaining subsistence-based traditions, scientists can gain a clearer understanding of the baseline parameters and limitations of human health shaped by millions of years of evolution.
The implications of these findings extend far beyond anthropological curiosity. They raise the prospect of novel therapeutic avenues that harness elements of traditional immune conditioning without the detrimental consequences of parasitic infection. For example, Trumble envisions the future development of immunomodulatory drugs derived from proteins found on parasitic worms such as hookworms. Such pharmaceuticals could “trick” the human immune system into adopting a regulatory state that reduces harmful chronic inflammation, paralleling how vaccines exploit controlled pathogen exposure to prepare immune defenses against viral threats.
Nevertheless, the researchers caution that no single intervention is likely to serve as a panacea. The complex interplay of diet, physical activity, microbial environment, and genetics all converge to shape an individual’s immunological trajectory. The Tsimane’s diverse lifestyle factors—including their nutrient-dense diet, active physical routines, and balanced pathogen exposure—likely act in concert to blunt inflammaging. Deciphering the relative contributions and mechanisms of these elements will require extensive longitudinal studies and multidisciplinary collaboration.
Future investigations spearheaded by Aronoff and colleagues aim to dissect these variables further. Ongoing research plans include detailed analyses of nutritional intake, patterns of physical exertion, and the spectrum of infectious agents encountered by the Tsimane. By integrating these data with immunological profiles and health outcomes, the team hopes to build a comprehensive picture of how human aging can proceed in the absence of excessive chronic inflammation.
This paradigm shift invites a reevaluation of aging itself, suggesting that the progressive inflammation so commonly observed in industrialized populations is not an intrinsic feature of human biology but rather a consequence of modern environmental mismatches. Understanding the evolutionary roots of immune function and the conditions that preserve immune homeostasis opens exciting possibilities for counteracting age-associated diseases that currently burden public health systems worldwide.
The study’s findings emphasize that to authentically improve healthspan and lifespan, biomedical research must consider the evolutionary and ecological context of human physiology. By learning from communities like the Tsimane—who occupy a living window into humanity’s distant past—scientists can uncover strategies to mitigate the detrimental effects of inflammation without relying solely on pharmacological interventions.
As the global population continues to age rapidly, insights gleaned from such pioneering research could inform public health policies aimed at fostering lifestyle environments conducive to healthy aging. Efforts to promote physical activity, balanced nutrition, and potentially controlled immune system modulation might help reconcile our ancestral biology with the demands of modern life, reducing the burden of chronic inflammatory diseases.
Ultimately, this research not only redefines a key aspect of the aging process but also heralds a new era of integrative medicine rooted in evolutionary understanding. It challenges assumptions long held as immutable and reaffirms the importance of bridging anthropology, immunology, and medicine to solve some of the most pressing health challenges of the 21st century.
Subject of Research: People
Article Title: Inflammaging is minimal among forager-horticulturalists in the Bolivian Amazon
News Publication Date: 20-Aug-2025
Web References: https://royalsocietypublishing.org/doi/10.1098/rspb.2025.1111
References: Proceedings of the Royal Society B Biological Sciences
Keywords: Anthropology, Evolutionary biology
