As the global population ages, the prevalence of chronic low-grade inflammation—often termed “inflammaging”—has become a pressing public health issue. This silent inflammatory state not only accelerates biological aging but also contributes to the onset of metabolic, cardiovascular, and neurodegenerative diseases.
Recent scientific attention has focused on the gut microbiome as a key regulator of this process, linking diet, microbial metabolism, and systemic immune responses. Among dietary components, polyphenols, naturally occurring compounds abundant in fruits, vegetables, tea, and cocoa, have emerged as promising modulators of both gut microbiota and inflammation.
A team led by Simone Guglielmetti from the University of Milano-Bicocca and Giorgio Gargari from the University of Milan has provided new scientific evidence to deepen the understanding of the relationship between polyphenol-rich diets and healthy aging.
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In this randomized crossover clinical trial, 50 participants aged 60 and above followed either a polyphenol-rich diet (PR-diet) or a control diet for eight weeks. The PR-diet included polyphenol-dense foods such as berries, apples, green tea, and dark chocolate. Using advanced metagenomics and metabolomics analyses, researchers examined changes in gut microbial composition and metabolic pathways.
Pro-inflammatory markers
The results were remarkable. Participants with higher baseline inflammation showed significant reductions in pro-inflammatory markers—particularly interleukin-6 (IL-6) and C-reactive protein (CRP)—after consuming the PR-diet. At the same time, beneficial bacterial genera such as Blautia and Dorea became more abundant, and microbial diversity improved.
Metabolomic profiles revealed increased levels of polyphenol-derived metabolites linked to anti-inflammatory and antioxidant activity, highlighting a biochemical bridge between diet, microbiota, and host immunity.
According to the authors, these findings demonstrate that polyphenol-rich diets can serve as a simple, safe, and effective nutritional strategy to counteract inflammation and support healthy aging. More importantly, the results underscore the value of stratifying older adults by their inflammatory and microbial profiles to optimize dietary interventions. By integrating multi-omics approaches, the MaPLE study provides a model for understanding the complex interactions between diet, gut microbes, and host physiology.
Looking forward, future research will focus on identifying the most bioactive polyphenol compounds and exploring their synergistic roles within the gut–immune axis. As science continues to unravel how food components shape human health, this study reinforces a fundamental message: what we eat not only nourishes our bodies but also shapes the invisible microbial ecosystems that protect us from within.
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