Intake of Live Microorganisms in Adults and Its Impact on Microbiota and Health Parameters

The intake of live microorganisms (LMOs) may contribute to modulating gut microbial ecology with an impact on health. In this study, we examined the intake of LMOs in adults and its association with gut microbiota composition, intestinal short-chain fatty acids (SCFAs), and health-related biochemical parameters. A total of 151 adults were analyzed across three age groups (18–50, 51–65, and 66–95 years). Dietary intake was assessed using a food frequency questionnaire (FFQ), and LMOs consumption was estimated with a previously developed database. The levels of some relevant intestinal microbial groups were measured using Quantitative Polymerase Chain Reaction (qPCR), SCFAs were determined using gas chromatography, and biochemical markers were assessed through standardized laboratory methods. LMOs intake was significantly higher in the two older age groups compared with younger adults, with yogurt identified as the primary dietary source of LMOs across all ages. In the middle-aged group, bacterial LMOs intake independently predicted higher abundances of Akkermansia and Bacteroides-related taxa, while fungal LMOs were positively associated with butyric acid levels. In the older age group, bacterial LMOs intake was directly associated with branched-chain fatty acids (BCFAs) while fungal LMOs intake was directly associated with circulating cholesterol and inversely with malondialdehyde (MDA). Overall, the findings suggest that LMOs consumption, mainly bacteria intake from fermented dairy products, increases with age and is linked to age-specific changes in gut microbiota, microbial metabolites, and biochemical health parameters.