The urinary phenolic acid profile varies between younger and older adults after a polyphenol-rich meal despite limited differences in in vitro colonic catabolism

Alkhaldy, A., Edwards, C. A. and Combet, E. (2019) The urinary phenolic acid profile varies between younger and older adults after a polyphenol-rich meal despite limited differences in in vitro colonic catabolism. European Journal of Nutrition, 58(3), pp. 1095-1111. (doi: 10.1007/s00394-018-1625-1) (PMID:29488010) (PMCID:PMC6499760)

Abstract

Purpose: To investigate whether age influences colonic polyphenol metabolism. Methods: Healthy participants, younger (n = 8; 23–43 years) and older (n = 13; 51–76 years), followed a 3-day low-polyphenol diet (LPD) and a 3-day high-polyphenol diet (HPD). Urinary phenolic acids (PA), short chain fatty acids (SCFA), pH and gas were monitored, alongside selected colonic bacteria. Human faecal in vitro fermentations of rutin with or without raftiline were used to evaluate the gut microbiota capacity in a subset of both groups. Results: Total urinary PA were higher in the older group after HPD compared to the younger group (1.5-fold; p = 0.04), with no difference between groups in terms of a change between diets (Δ high-low diet). While 17 PA were detected in all younger participants after HPD, a narrower range (n = 8 to 16 PA) was detected in most (n = 9/13) older participants, with lower level of benzoic acid (19-fold; p = 0.03), vanillic acid (4.5-fold; p = 0.04) but higher hippuric acid (2.7-fold; p = 0.03). Faecal SCFA concentration did not change after HPD within group, with similar differential excretion (Δ high-low diet) between groups. There were no differences between groups for faecal pH, total, faecal bacteria including Flavonifractor plautii, bifidobacteria, and bacteroides. In human in vitro faecal fermentations, seven PAs were detected in both groups after 24 h of rutin fermentation, with no quantitative and modest qualitative differences between groups. Total SCFA in faecal fermentation did not differ between groups, except for butyric acid (twofold higher in the older group; p = 0.009) when rutin was fermented with raftiline over 24 h. Conclusions: Urinary phenolic acids were less diverse in older participants despite limited difference in functional capacity of in vitro faecal fermentations.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Combet Aspray, Professor Emilie and Edwards, Professor Christine
• Authors: Alkhaldy, A., Edwards, C. A., and Combet, E.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: European Journal of Nutrition
• Publisher: Springer
• ISSN: 1436-6207
• ISSN (Online): 1436-6215
• Published Online: 27 February 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in European Journal of Nutrition 58(3): 1095-1111
• Publisher Policy: Reproduced under a Creative Commons License