A Comprehensive Review of Oral Probiotic Supplementation in Adults: Implications for Inflammatory Bowel Disease
Authors: shafik Ali Ismail ahmed , Shafik Ahmed Ismail ahmed 
Published: November 2023

Abstract
Purpose
Probiotics may offer a simple and appealing approach to prevent or treat inflammatory bowel disease (IBD). Patients are drawn to the idea of probiotics because they are considered "safe," nontoxic, and natural, establishing probiotics as a cornerstone of gastrointestinal (GI) health. However, while this concept appears straightforward, it can be frustratingly misleading. As we will explore later, researchers have been left perplexed and bewildered. It wouldn't be surprising for someone, especially in the field of biology, to claim they understand probiotics, but the truth is, those who say they understand probiotics truly don't comprehend their full complexity. This literature review aims to establish a new understanding of probiotics, presenting a realistic assessment. In this review, we will provide a concise history of probiotics, outlining their various types, uses, effects, implications, and common misconceptions, while also discussing potential future implications of these humble microorganisms.
Method
PubMed, Scopus, Egyptian Knowledge Bank (EKB), and Google Scholar were searched for studies on oral probiotic supplementation in healthy adults. Inclusion criteria comprised clinical trials and observational studies published in English, while exclusion criteria included pediatric populations, animals, and specific medical conditions. Relevant data, including probiotic interventions, outcome measures, and findings on immune markers, disease stages, and combination therapy, were extracted and critically evaluated for quality and bias. The review incorporated meta-analyses, retrospective studies, and cohort studies to provide a comprehensive overview. Limitations include study heterogeneity, potential publication bias, and limited high-quality evidence. Nonetheless, the review offers valuable insights into the effects of probiotics in healthy adults and their implications for disease management.
Results
The review found inconsistent effects of oral probiotic supplementation on immune and inflammatory markers in healthy adults. Evidence regarding the benefits of probiotics in different stages of inflammatory bowel disease (IBD) was lacking. Combination therapy with probiotics showed promise in improving disease scores and reducing adverse effects in IBD, but optimal combinations and dosages remain unclear. Notably, there was limited clinical significance of probiotics in ulcerative colitis (UC) compared to Crohn's disease (CD).
Conclusion
Overall, the review highlights the limited evidence and variability in the effects of oral probiotics on immune and inflammatory markers in healthy individuals. More research is needed to determine the potential benefits of probiotics in different stages of IBD and to establish optimal combinations for effective treatment. It is worth noting that while probiotics have shown potential for Crohn's disease, their clinical significance in ulcerative colitis appears to be limited. Further investigation is necessary to better understand the differential responses to probiotic therapy between these two types of inflammatory bowel disease.