Metabolic characteristics of the faecal microflora in humans from three age groups

Background: Little is known about the influence of the ageing process on the bacterial metabolism. The aim of this work was to study the inter-individual variation and the influence of age on metabolic characteristics of the faecal microflora from persons of three age groups. Methods: Nine enzyme activities and 11 metabolites were analysed in faecal samples of 21 elderly persons (69-89 years of age), 15 adults (30-46 years of age) and 14 children (3-15 years of age). Results: They provide a pattern of the faecal micro? ora metabolism in a French population aged between 3 and 89 years. They showed large inter-individual differences in the three groups. Although the enzyme activities were not significantly different between groups, glycolytic activities appeared less variable in adults than in elderly persons and children. The major metabolites (acetate, propionate, butyrate and L-lactate) resulting from carbohydrate fermentation were similar in the three groups. Samples from elderly persons were characterized by higher D/L lactate ratio and higher concentrations of metabolites resulting from protein fermentation (ammonia, valerate, iso-butyrate and iso-valerate). Conclusion: The data showed significant differences between elderly persons and younger adults and children, but the major metabolic characteristics of the faecal microflora were not greatly altered by the ageing process.