Introduction
diarrhea-predominant, GI distress
IRRITABLE BOWEL SYNDROME (IBS)
The human gut microbiota is a key mediator of host health and is known to affect many physiological processes, such as digestion, metabolism, immune function and inhibition of pathogen colonization (The gut microbiome can be impacted by many extrinsic factors including diet, stress, immunosuppressants, antibiotics, surgery, and radiotherapy, resulting in changes in bacterial abundance and diversity (Probiotics are defined as ‘non-pathogenic live micro-organisms that, when administered in adequate amounts, confer a health benefit to the host’ (The effectiveness of the 14 strain probiotic blend has been assessed in several randomized, placebo-controlled trials (RCTs). The 14 strain blend was reported to be safe and efficacious, improving various aspects of GI distress over a period of 4 months in irritable bowel syndrome (IBS) diarrhea-predominant subjects (Yet, among these positive results, there are no data evaluating the effects of the 14 strain blend on the fecal microbiome in healthy individuals. While there is no scientific consensus on what constitutes a “healthy” microbiome, healthy populations are known to present variations in microbiota patterns. These variations have been attributed to a wide variety of factors, including age, diet, lifestyle habits, cohabitants, and many others, however research demonstrating how probiotic supplements interact with and modulate the gut microbiota and exert positive effects on healthy adults remains limited (Historically, most research has focused on understanding the effect of probiotics on compositional changes to the microbiota and relatively little research has focused on functional changes. Compositional outcomes include alpha diversity, beta diversity, differential abundance across taxonomic levels whereas functional alterations measure actual (metagenomic) differential abundance of microbial genes. Therefore, the primary focus of this study was to assess both compositional and functional changes in the microbiome of healthy individuals using shotgun metagenomics following 8-weeks of daily multi-strain probiotic intake. Additional measurements included examining correlations between microbiota and hydrogen and methane production from breath samples, determination of changes in stool frequency and consistency, and analysis of fecal biochemistry.