Polyphenol metabolism in the ageing gut: Comparative analysis of olive polyphenol biotransformation between healthy young and elderly

Life expectancy has never been higher and is predicted to keep rising, shifting the demographic profile to an older population. Ageing is often accompanied by comorbidities and polypharmacy, thereby increasing healthcare system demands [ 1 ]. A healthy diet is crucial for longevity and disease prevention, and research into age-related changes in the gastrointestinal tract and the biotransformation of bioactive compounds is becoming increasingly relevant [ 2 ]. This research aims to adapt an in-house validated in vitro. Literature was reviewed for changes in transit time, pH, enzyme activity, and gut microbiome composition during ageing [ 3 ] [ 4 ]. Biotransformation experiments with olive leaf extract resulted in various metabolites due to deglycosylation, hydrolysis, (de)methylation, and flavonoid ring cleavage. Both age groups formed the same metabolites, but the elderly showed a higher biotransformation rate, possibly due to lower viable cell count in the younger population’s faecal pool [ 5 ]. In conclusion, the experiments indicate that polyphenols maintain their potential health benefits in healthy elderly individuals since similar biotransformation patterns were observed. Further research on the ageing gastrointestinal tract is essential for advancing research in healthy ageing. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany