Summary: Polyphenols may reduce inflammation in the elderly by altering the gut microbiota and inducing the production of indole 3-propionic acid.
Source: University of Barcelona
Polyphenols present in the foods we eat can prevent inflammation in the elderly since they alter the intestinal microbiota and induce the production of indole 3-propionic acid (IPA), a metabolite resulting from the degradation of tryptophan due to intestinal bacteria.
This study, published in Molecular nutrition and food researchwas carried out by the Research Group on Biomarkers and Nutritional and Food Metabolomics of the Faculty of Pharmacy and Food Sciences of the University of Barcelona and the CIBER on Frailty and Healthy Aging (CIBERFES) .
The team, led by Professor Cristina Andrés-Lacueva, from UB’s Faculty of Pharmacy and Food Sciences, is also a member of the Catalonia Food Innovation Network (XIA).
Polyphenols and healthy aging
Polyphenols are natural compounds, considered probiotics, that we consume mainly through fruits and vegetables. Several dietary polyphenols have well-known antioxidant and anti-inflammatory properties and the ability to interact with bacteria in the human gut and produce postbiotics (like IPA), increasing their positive health effects.
A growing body of evidence confirms that regular consumption of polyphenols in the diet may contribute to healthy aging, especially if they are part of a healthy diet, such as the Mediterranean diet, and are combined with a healthy lifestyle, i.e. including regular physical activity and excluding tobacco and alcohol, for example.
The study shows that the interaction between polyphenols and the intestinal microbiota can induce the proliferation of bacteria capable of synthesizing beneficial metabolites, such as IPA. IPA is a postbiotic with antioxidant, anti-inflammatory and neuroprotective properties that help improve the health of the intestinal wall. This compound appears to help prevent certain diseases associated with aging.
“Considering the beneficial effects of IPA on the gut microbiota and overall health, it is important to find reliable strategies to promote the production of this metabolite,” notes the co-first signatory of the study. , Tomás Meroño, from the Department of Nutrition, Food Science and Gastronomy of UB and CIBERFES.
As part of the study, the researchers performed a multiomics analysis to monitor serum IPA levels. The researchers analyzed the composition of the intestinal microbiota in faecal samples from fifty-one volunteers over the age of sixty-five who followed a diet rich in polyphenols (including the consumption of green tea, bitter chocolate, fruits including apples, pomegranate and blueberries) for eight weeks.
Increased blood IPA and bacterial growth
The results show that the polyphenol-rich diet generated a significant increase in IPA levels in the blood, as well as a decrease in inflammation levels and changes in gut bacteria of the order Bacteroidales.
Surprisingly, the researchers did not observe the same effects in volunteers with kidney disease. This could be explained by the altered composition of their gut microbiota. These people had lower amounts of IPA at the start of the trial compared to volunteers with normal kidney function.
“These results could be clinically relevant since low levels of IPA have been associated with a rapid decline in kidney function and chronic kidney disease,” notes Professor Cristina Andrés-Lacueva.
Therefore, a diet rich in polyphenols, including probiotic foods such as green tea, dark chocolate and certain fruits such as apples, pomegranate and blueberries, could increase IPA production by altering the composition of the gut microbiota. This increase in levels of a postbiotic such as IPA in the elderly could be beneficial in delaying or preventing chronic diseases that impair quality of life.
The study also includes the participation of teams from the University of Milan (Italy), the Quadram Institute (UK) and the National Institute of Health and Aging Sciences (INCRA, Italy), among other institutions.
About this diet and current inflammation research
Author: Rosa Martinez
Source: University of Barcelona
Contact: Rosa Martínez – University of Barcelona
Image: Image is in public domain
Original research: Free access.
“A diet rich in polyphenols increases the indole 3-propionic metabolite of the intestinal microbiota in elderly people with preserved renal function” by Tomás Meroño et al. Molecular nutrition and food research
A diet rich in polyphenols increases the indole 3-propionic metabolite of the intestinal microbiota in elderly people with preserved renal function
Dietary polyphenols can alter the gut microbiota (GM) and promote the production of bioactive metabolites. Several indoles resulting from GM metabolism of dietary tryptophan have been associated with gut barrier integrity. Our aim is to investigate changes in GMO-derived indoles during high polyphenol (PR) diet intervention in the elderly.
Methods and results
Randomized, controlled, crossover trial in adults ≥60 years living in a residential care facility during an 8-week PR regimen versus a control regimen (not = 51). Seven GM-tryptophan metabolites are measured in serum and metataxonomic analysis of GM is performed on fecal samples.
Exploratory subgroup analyzes are performed according to renal function (RF). The PR diet significantly increased serum indole 3-propionic acid (IPA) in subjects with normal RF, but not in subjects with impaired RF. Other GM-tryptophan metabolites are not affected.
Comparison of baseline GM composition shows changes in members of the order Bacteroidales as well as greater abundance of Clostridiales in participants with normal RF. Over the course of the assay, changes in IPA are associated with changes in C-reactive protein (β = 0.32, p = 0.010) and GM, especially with the Clostridiales (r = 0.35, p < 0.001) and Enterobacteriaceae (r = −0.15, p < 0.05) commands.
A PR diet increases serum IPA concentration in older adults with normal RF. Our findings may be important when defining appropriate dietary interventions for the elderly.
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