Medically reviewed by Onikepe Adegbola, MD, PhD
While irritable bowel syndrome (IBS) is very prevalent in individuals today, science still does not fully understand the exact mechanism behind it. However, researchers do have evidence to support the relationship between bacteria in the gut and IBS symptoms.
The gut microbiome, or gut microbiota, is a community of healthy (and sometimes unhealthy) bacteria and other microorganisms living in the gastrointestinal tract. A balanced and healthy gut microbiome has many health benefits to its host beyond simply gut health, including a lower risk of many chronic disease states. The gut microbiome is so crucial to human health and well-being that it is often dubbed an “organ.”
While the gut microbiome does not change too drastically after development early in life, lifestyle factors can influence the types of bacteria present and the balance of healthy bacteria. These factors include diet and medication, which can disrupt the natural balance, or homeostasis, in the gut bacteria. Additionally, the gut microbiome can be altered, creating a state called gut dysbiosis through antibiotic use specifically. Antibiotic use has increased 66% since 2000 and is still on the rise. Therefore, researchers should study how antibiotics impact the gut microbiome, potentially contributing to IBS development.
Researchers from Sechenov First Moscow State Medical University analyzed data existing in the body of literature regarding antibiotic use, how this altered the bacteria in the gut, and the prevalence of irritable bowel syndrome. The literature review, “Antibiotics, gut microbiota, and irritable bowel syndrome: What are the relations?” was published in the World Journal of Gastroenterology in March 2022.
Previous research has supported the relationship between gut dysbiosis and IBS. This relationship may be due to the decreased diversity, or variety, of bacteria in the gut of patients with IBS and less of certain beneficial bacteria, such as Bifidobacterium.
When it comes to antibiotics, there is conflicting research as well. However, a commonality of most of the studies concluded a relationship between antibiotic use and altered gut microbiota. Researchers believe this may be due to antibiotics taking similar pathways through the body as microbial processes.
Additionally, studies have demonstrated antibiotic medication’s ability to reduce the resistance of bacteria to harmful colonization. For example, a healthy gut microbiome with antibiotic use would, perhaps, struggle to resist the growth of harmful bacteria, such as Clostridium difficile.
A concept proposed entitled the “microbiome-gut-brain” axis suggests that when the gut microbiome is altered (such as through antibiotic use), the barrier of the intestines is damaged. When the intestinal wall is harmed, inflammation and immune response initiate, which can often lead to symptoms of IBS. These symptoms include bloating, abdominal pain, and changes in bowel habits (such as diarrhea or constipation).
In other words, experimental and observational evidence suggests that patients with IBS experience gut microbiome dysbiosis or imbalance. Also, antibiotic use can similarly impact the gut microbiome. However, research in this area remains conflicting. Therefore, more large-scale studies need to be completed to solidify the relationship between antibiotics, the gut microbiome, and IBS.
Mamieva, Z., Poluektova, E., Svistushkin, V., Sobolev, V., Shifrin, O., Guarner, F., & Ivashkin, V. (2022, March 28). Antibiotics, gut microbiota, and irritable bowel syndrome: What are the relations? World Journal of Gastroenterology. Retrieved May 11, 2022, from https://www.wjgnet.com/1007-9327/full/v28/i12/1204.htm