A diet rich in polyphenols can prevent inflammation in the elderly

Summary: Polyphenols reduce inflammation in the elderly by altering the intestinal microbiota and inducing the production of indole 3-propionic acid.

A source: University of Barcelona

The polyphenols in the food we eat prevent inflammation in the elderly, as they alter the intestinal microbiota and produce indole 3-propionic acid (IPA), a metabolite derived from tryptophan degradation by intestinal bacteria.

This study was published Molecular nutrition and nutrition researchThe study was conducted by the Research Group on Biomarkers and Nutrition and Food Metabolism of the Faculty of Pharmacy and Food Science of the University of Barcelona and CIBER (CIBERFES) on brittle and healthy aging.

The team, led by Kristina Andres-Lakueva, a professor at the UB Faculty of Pharmacy and Food Science, is also a member of the Catalan Food Innovation Network (XIA).

Polyphenols and healthy aging

Polyphenols are natural compounds that are considered probiotics, and we eat them mainly through fruits and vegetables. Several dietary polyphenols have known antioxidant and anti-inflammatory properties and can interact with bacteria in the human gut to produce postbiotics (such as IPA), which increase their health benefits.

There is growing evidence that regular use of polyphenols in the diet contributes to healthy aging, especially if they are part of a healthy diet, such as the Mediterranean, and with a healthy lifestyle, including non-smoking and non-alcoholic exercise. .

Studies show that the interaction between polyphenols and intestinal microbiota can lead to the growth of bacteria with the ability to synthesize beneficial metabolites such as IPA. IPA is a postbiotic with antioxidant, anti-inflammatory and neuroprotective properties that contribute to improving the health of the intestinal wall. This compound helps prevent some of the diseases associated with aging.

“If we take into account the beneficial effects of IPA on intestinal microbiota and overall health, it is important to find reliable strategies to promote the production of this metabolite,” said Thomas Meronio of the department, the study’s first signatory. UB and CIBERFES nutrition, food science and gastronomy.

As part of the study, the researchers performed a multimedia analysis to monitor IPA levels in serum. Researchers analyzed the intestinal microbiota in the fecal samples of fifty-one volunteers over the age of sixty-five who followed a polyphenol-rich diet for eight weeks (including green tea, dark chocolate, fruits, apples, pomegranates, and blueberries). .

Increase IPA in the blood and bacterial growth

The results showed that a diet rich in polyphenols led to a significant increase in blood IPA levels, along with a decrease in the level of inflammation and changes in the intestinal bacteria from the Bacteroidales order.

Polyphenols are natural compounds that are considered probiotics, and we eat them mainly through fruits and vegetables. Image in public domain

Surprisingly, the researchers did not find the same effect in volunteers with kidney disease. This can be explained by the changed composition of their intestinal microbiota. These individuals showed lower IPA at the beginning of the test compared to volunteers with normal kidney function.

Professor Kristina Andres-Lakueva notes: “These results may be clinically relevant because low levels of IPA are associated with rapid decline in kidney function and chronic kidney disease.”

Therefore, a polyphenol-rich diet, including probiotic foods such as green tea, dark chocolate, and fruits such as apples, pomegranates, and blueberries, can increase IPA production by altering the composition of the intestinal microbiota. Increased levels of postbiotics, such as IPA in the elderly, may be helpful in delaying or preventing chronic diseases that affect quality of life.

The study also included teams from the University of Milan (Italy), the Quadrama Institute (UK) and the National Institute for Aging Health and Science (INCRA, Italy).

It’s about diet and inflammation research news

Author: Rosa Martinez
A source: University of Barcelona
The connection: Rosa Martinez – University of Barcelona
Photo: Image in public domain

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Original study: Open access.
“A polyphenol-rich diet increases indole 3-propionic acid, a metabolite of the intestinal microbiota, in older men with impaired renal function,” Thomas Meronio et al. Molecular Nutrition & Food Research


A polyphenol-rich diet increases indole 3-propionic acid, a metabolite of the intestinal microbiota, in older people with impaired renal function.


Dietary polyphenols can alter intestinal microbiota (GM) and promote the production of bioactive metabolites. Several indols of GM metabolism of tryptophan in food are associated with the integrity of the intestinal barrier. Our goal was to study changes in GM-derived indones during polyphenol-rich (PR) diet interventions in the elderly.

Methods and results

Randomized, controlled, crossover test for 60-year-olds living in a boarding school during an 8-week PR-controlled diet (do not = 51). Seven GM-tryptophan metabolites are measured in serum, and metataxonomic analysis of GM is performed in feces samples.

Analysis of research subgroups is based on renal function (RF). PR-diet significantly increases serum indole 3-propionic acid (IPA) in subjects with normal RF, but not in subjects with RF impairment. No other GM-tryptophan metabolites are affected.

Comparison of basal GM composition shows displacements of Bacteroidales order members, as well as the presence of Clostridiales in participants with normal RF. Variations of IPA during the test were associated with changes in C-reactive protein (β = 0.32, P = 0.010) and GM, especially with Clostridiales (р = 0.35, P <0.001) and Enterobacterial (р = −0,15, P <0.05) commands.


Diet PR increases serum concentrations of IPA in older people with normal RF. Our findings may be important in determining proper nutrition for older people.

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