Probiotics and Prebiotics Play a Crucial Role in Gut Health

Probiotics and prebiotics play a crucial role in gut health and provide the gastrointestinal tract with the healthy bacteria it needs to thrive. Individuals diagnosed with irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO) often experience uncomfortable digestive symptoms, including abdominal pain, bloating, or flatulence. Studies have demonstrated the effectiveness of some strains of bacteria in probiotics and fiber in prebiotics in decreasing the symptoms of these gastrointestinal disorders.

Probiotics and Digestive Health

Probiotics contain “friendly” or good bacteria similar to the healthy bacteria currently living in the gastrointestinal tract. They help balance out the harmful bacteria that may be present in the gut and help fight disease. Probiotics can be consumed through foods, such as kefir, kombucha, or yogurt, or can be added to supplements. 

The community of bacteria and microorganisms in the gastrointestinal tract is called the gut microbiota, or gut microbiome. 

Ideally, a majority of the gut microbiome should be healthy bacteria so that when harmful bacteria intrudes, the microbiome can fight against it. In addition, the gut microbiota works together to promote a healthy digestive system, immune system, and much more. Bacteria may even induce many gastrointestinal diseases, so it is crucial that beneficial bacteria make up the gut microbiota (Gutierrez & Domingo-Calap, 2020). 

In a meta-analysis and literature review on the effects of probiotics on IBS symptoms, out of 35 studies, seven reported that IBS patients receiving a probiotic had an improvement in IBS symptoms compared to those receiving a placebo control supplement (Dale, Rasmussen, Asiller, & Lied, 2019). Additionally, the meta-analysis found the highest effectiveness in participants who received multiple strains of different bacterium and used the probiotics over a long period. 

Let’s discuss some bacterial key players in promoting gut health and even potentially reducing the symptoms of irritable bowel syndrome. 

Bacillus subtilis, or B. subtilis, is a bacterial strain used in probiotics for its immune health benefits. Studies have shown a potential benefit to the immune system in the elderly population specifically (Lefevre et al., 2016). Therefore, B. subtilis is used as an additive probiotic in both food and supplements. Additionally, laboratory and experimental assessments demonstrated the safety of B. subtilis in healthy subjects.

Another bacterial strain is Bacillus coagulans or B. coagulans. The Natural Medicines Comprehensive Database has rated B. coagulans as “possibly effective” or irritable bowel syndrome (National Library of Medicine & U.S. Department of Health and Human Services, 2021). However, B. coagulans have insufficient evidence to conclude effectiveness for individuals diagnosed with small intestinal bacterial overgrowth. 

Lactobacillus acidophilus, or L. acidophilus, is one of the most common bacterial strains in probiotics. This bacteria is typically found in the mouth and intestine (Mayo Clinic, 2020). In addition, dairy products, such as yogurt, may contain L. acidophilus in dietary form. Like B. coagulans, research has shown L. acidophilus to be “possibly effective” in treating IBS, but not SIBO (Multum, 2021). 

Let’s move on to another good bacteria. Bifidobacterium lactis, or B. lactis, has been clinically shown to have probiotic characteristics, including strong mucus adherence properties. Additionally, B. lactis may have beneficial effects on gut health and digestion. In clinical trials studying a compound containing B. lactis, participants experienced a reduction in diarrhea, including diarrhea associated with antibiotic use, and increased bowel functioning (Jungersen et al., 2014). B. lactis may even aid in the body’s resistance to respiratory tract infections.

Prebiotics and Digestive Health

Let’s switch gears to prebiotics. Prebiotics are the “food” for the healthy bacteria in the gut, often provided by probiotics. Prebiotics are typically forms of fiber and can be found in fruits and vegetables, for example. 

In a randomized, placebo-controlled, double-blind clinical trial, participants were healthy individuals with gastrointestinal distress, and researchers wanted to see changes in their gut microbiome after receiving a combination of the following compounds (Gutierrez & Domingo-Calap, 2020):

LH01 - myoviridae

LL5 - siphoviridae

T4D - myoviridae

LL12 - myoviridae

The above compounds are called bacteriophages consumed in a prebiotic supplement form.

In the study (2020), participants experienced improved blood markers associated with chronic diarrhea. Additionally, enzymes related to inflammation and tissue damage were significantly decreased compared to the placebo (Gutierrez & Domingo-Calap, 2020). This study leads researchers to conclude that the compounds LH01 - myoviridae, LL5 - siphoviridae, T4D - myoviridae, and LL12 - myoviridae may contribute to beneficial effects to gut health and digestion. 

Overall, probiotics and prebiotics are dietary compounds shown to promote digestive health and support a healthy gut microbiome.


Dale, H. F., Rasmussen, S. H., Asiller, Ö. Ö., & Lied, G. A. (2019, September 2). Probiotics in Irritable bowel syndrome: An up-to-date systematic review. Nutrients. Retrieved May 13, 2022, from 

Gutiérrez, B., & Domingo-Calap, P. (2020, September 16). Phage therapy in gastrointestinal diseases. Microorganisms. Retrieved May 13, 2022, from 

Jungersen, M., Wind, A., Johansen, E., Christensen, J. E., Stuer-Lauridsen, B., & Eskesen, D. (2014, March 28). The science behind the probiotic strain bifidobacterium animalis subsp. lactis BB-12(®). Microorganisms. Retrieved May 13, 2022, from 

Lactobacillus acidophilus uses, side effects & warnings. (n.d.). Retrieved May 13, 2022, from 

Lefevre, M., Racedo, S. M., Denayrolles, M., Ripert, G., Desfougères, T., Lobach, A. R., Simon, R., Pélerin, F., Jüsten, P., & Urdaci, M. C. (2016, November 5). Safety assessment of bacillus subtilis CU1 for use as a probiotic in humans. Regulatory Toxicology and Pharmacology. Retrieved May 13, 2022, from 

Mayo Foundation for Medical Education and Research. (n.d.). Drugs and supplements - drugs and supplements. Mayo Clinic. Retrieved May 13, 2022, from 

U.S. National Library of Medicine. (n.d.). Bacillus coagulans: Medlineplus supplements. MedlinePlus. Retrieved May 13, 2022, from 

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