Many adults develop higher levels of chronic, low-grade inflammation as they age, which can affect how the body responds to stress, illness and everyday health challenges. A new clinical trial suggests that eating more foods naturally rich in polyphenols may help reduce some of these inflammatory markers, especially in people who start out with higher inflammation levels.
Polyphenols are natural compounds found in many plant foods. They are especially abundant in berries, apples, plums, leafy greens, nuts, tea, coffee, cocoa and spices. Researchers have long been interested in how these compounds interact with the gut microbiome and whether they might play a supportive role in healthy aging.
In the MaPLE study, 50 adults age 60 and older followed either a polyphenol-rich diet or a control diet for eight weeks before switching plans. The polyphenol-rich diet included foods such as berries, apples, green tea and dark chocolate. Throughout the study, which was published in Microbiome Research Reports, researchers collected stool and blood samples and analyzed changes in gut microbes and diet-related metabolites.
Participants who started with higher inflammation showed the most notable response. These individuals experienced reductions in interleukin-6 and C-reactive protein after eating the polyphenol-rich diet. The researchers also observed shifts in gut microbes and increases in compounds formed when the body breaks down polyphenols. Those changes suggest that the gut microbiome may help process these foods in ways that influence inflammation.
The study did not track long-term health outcomes, so the findings are limited to short-term changes in biological markers. Still, the trial offers insight into how certain plant foods may interact with the gut and immune system as people age. The researchers plan to study which specific polyphenols have the strongest effects and how different gut microbes may contribute.
For now, the results add to existing evidence that including a variety of plant foods in the diet may support healthy aging, particularly for older adults with higher baseline inflammation.
This research was conducted as part of the MaPLE project, funded through the European Joint Programming Initiative “A Healthy Diet for a Healthy Life.” Support came from agencies in Italy, Spain and the United Kingdom, along with the European Regional Development Fund. Additional grants were provided by the Biotechnology and Biological Sciences Research Council in the UK, the Generalitat de Catalunya, the Instituto de Salud Carlos III and several European research programs focused on nutrition and microbiome science.