Effects of a Saccharomyces uvarum Cell-Based Preparation on Gut Microbial Ecology and Metabolic Activity in Adults Without Diagnosed Gastrointestinal Disease: A Randomized Placebo-Controlled Crossover Pilot Study

Background/Objectives: Yeast-based probiotic candidates are increasingly investigated as potential modulators of gut ecology, although evidence in healthy individuals remains limited. This randomized, single-blind, crossover study primarily evaluated the tolerability of ATECREM Serius containing Saccharomyces uvarum SERIUS strain (>1010 CFU/g) and explored its effect on human gut microbiota.

Methods

Forty-four volunteers completed the crossover intervention consisting of 2 months of ATECREM Serius (TRT1) and 2 months of placebo (PLT1), separated by 2 weeks of wash-out. Fecal microbiota was profiled by 16S rRNA gene sequencing, while fecal and urinary volatile organic compounds (VOCs) were profiled by GC-MS. Fecal free amino acids (FAAs) were also measured.