A Mini Literature Review of Probiotics: Transforming Gastrointestinal Health Through Evidence-Based Insights

Abstract

As our understanding of the intricate interaction between gut bacteria and human health continues to expand, so too has interest in the ability of probiotics to manage gut microbiota and confer multiple health benefits to the host. The mini literature review focuses on the expanding potential of the use of probiotics in GI health, with a focus on probiotics' potential therapeutic advantages in a variety of gastrointestinal (GI) illnesses. Probiotics play a significant role in managing diarrhea and symptoms of irritable bowel syndrome with diarrhea (IBS-D) by modulating gut microbial communities. Specific probiotic strains have been found to reduce the abundance of harmful bacteria, regulate inflammatory markers like interleukin 6, and improve GI symptoms such as abdominal discomfort and stool consistency. Additionally, probiotic blends have shown potential for preventing GI infections and alleviating GI pain in IBS-D patients. Studies have demonstrated that certain multi-strain probiotics, including Bifidobacterium and Lactobacillus species, can significantly increase the frequency of bowel movements and reduce the proportion of individuals experiencing constipation. It has also been found that probiotic supplementation may reduce the incidence of postoperative complications and mortality, particularly in patients undergoing colorectal adenocarcinoma surgery. Additionally, probiotics have been associated with decreased levels of pro-inflammatory cytokines and improved clinical outcomes in patients with colorectal cancer. Furthermore, probiotics have been associated with enhanced digestive tolerance, reduced GI inflammation, and prolonged clinical remission in certain UC patients. Studies have also shown that probiotics, administered either directly to infants or pregnant women during the perinatal stage, can alleviate symptoms such as inconsolable crying and irritation associated with infant colic, improve bowel movement frequency in cases of functional constipation, and enhance overall conditions in premature infants, including reducing regurgitation and improving feeding tolerance. The review addresses both encouraging results and challenges with probiotic therapy, while also arguing for more studies to elucidate underlying mechanisms and enhance therapeutic techniques. As we traverse the complex field of probiotic therapy in the treatment of GI illnesses, researchers, physicians, and other healthcare professionals can benefit from the informative information provided by this study.

Keywords: colorectal cancer; constipation; diarrhea; dysbiosis; gastrointestinal diseases; gut microbiota; irritable bowel syndrome; probiotics; ulcerative colitis.

Figure 1. Intestinal microbes potentially play a vital role in host-microbiota interactions through luminal conversion

Nutrients ingested orally can be metabolized by intestinal microbes into bioactive compounds, influencing both host health and the intestinal microbiota. Key examples include gamma-aminobutyric acid (GABA) and short-chain fatty acids (SCFAs). Image Credits: Created With Biorender.com

Figure 2. Mechanisms of probiotics in the human GI tract

Probiotics have the potential to influence the composition of intestinal microbial communities and inhibit the proliferation of harmful pathogens by stimulating the host's production of β-defensin and Immunoglobulin A (IgA). Moreover, probiotics may strengthen the intestinal barrier by preserving tight junctions and promoting mucin production. Additionally, probiotics may modulate the immune system by regulating cytokine secretion through signaling pathways such as nuclear factor kappa B (NFκB) and mitogen-activated protein kinases (MAPKs), impacting the proliferation and differentiation of immune and epithelial cells. Furthermore, probiotics can regulate gut motility and pain perception by controlling pain receptor expression and neurotransmitter secretion. plgr: polymeric immunoglobulin receptor, APRIL: a proliferation-inducing ligand, STATs: signal transducer and activator of transcription proteins, Treg: regulatory T-cells, Th1: T helper cell type 1, Th2: T helper cell type 2, GI: gastrointestinal Image Credits: Created With BioRender.com

Figure 3. A schematic representation of the IBS pathophysiology

Psychological, physiological, and neuro-gastroenterological factors are thought to be involved in the generation of irritable bowel syndrome (IBS) symptoms, including bloating, abdominal pain, and altered motility. Image Credits: Created With BioRender.com