# Age-Dependent Differences in Postprandial Bile-Acid Metabolism and the Role of the Gut Microbiome

## TL;DR

This study finds that aging changes bile acid metabolism and gut microbes, which may affect nutrition and health in older adults.

## Contribution

The study identifies age-related differences in postprandial bile acid metabolism and gut microbiome composition.

## Key findings

- Elderly showed lower glycine conjugated CDCA and UDCA levels compared to young individuals.
- Higher abundances of Ruminiclostridium, Marvinbryantia, and Catenibacterium were observed in the elderly group.
- Aging is linked to reduced hunger, altered body composition, and increased cholesterol levels.

## Abstract

Ageing changes the impact of nutrition, whereby inflammation has been suggested to play a role in age-related disabilities such as diabetes and cardiovascular disease. The aim of this study was to investigate differences in postprandial bile-acid response and its effect on energy metabolism between young and elderly people. Nine young, healthy men and nine elderly, healthy men underwent a liquid mixed-meal test. Postprandial bile-acid levels, insulin, glucose, GLP-1, C4, FGF19 and lipids were measured. Appetite, body composition, energy expenditure and gut microbiome were also measured. The elderly population showed lower glycine conjugated CDCA and UDCA levels and higher abundances of Ruminiclostridium, Marvinbryantia and Catenibacterium, but lower food intake, decreased fat free mass and increased cholesterol levels. Aging is associated with changes in postprandial bile-acid composition and microbiome, diminished hunger and changes in body composition and lipid levels. Further studies are needed to determine if these changes may contribute to malnutrition and sarcopenia in elderly.