Irritable bowel syndrome (IBS) is a common functional disorder of the gastrointestinal tract, affecting 10-15% of the North American population. IBS is a diagnosis of exclusion, meaning that other conditions should be ruled out prior to assigning a diagnosis of IBS. This includes evaluating for inflammatory bowel disease, celiac disease, and parasitic infection, for example.
There are no definitive diagnostic laboratory markers for IBS, rather the condition is defined by symptoms. In fact, the term “syndrome” itself denotes a group of symptoms, versus a “disease” which typically has a defined cause. I often find that the term “IBS” is used loosely.
Let’s review the widely used Rome IV diagnostic criteria for IBS:
Recurrent abdominal pain, occurring at least 1 day per week in the last 3 months, associated with 2 or more of the following:
- Symptoms are related to defecation (either worsening or improving)
- Associated with changes in stool frequency (decreased or increased)
- Associated with changes in stool appearance (loose, hard, pellet-shaped, containing mucus, constipation or diarrhea, or a combination of these)
Therefore, in general terms, this syndrome is characterized by chronic abdominal pain and altered bowel habits.
Other symptoms often accompany the above, including bloating, flatulence, or burping. Stools that are bloody or greasy should always be worked up further for alternative diagnoses.
There are several treatment strategies for IBS. The approach should be personalized to the individual based on various factors, including symptom presentation and medical history. There are numerous influences that may contribute to the pathological process of IBS, including issues with intestinal motility, disruptions in the gut lining or nervous system function, and imbalances in gut bacteria, or “dysbiosis.”
The term “dysbiosis” describes the imbalances in microorganisms responsible for maintaining a harmonious environment in the digestive tract. These “good bacteria” help to promote healthy digestion and absorption of nutrients, immune function, and strong intestinal tissues. We can consume these healthy bacteria through probiotic foods and supplements.
A recent study published in Nutrients assessed the effectiveness of a multi-strain probiotic in adults with IBS-D (IBS that is diarrhea-predominant). Subjects were randomized to receive a mixture of Lactobacillus, Bifidobacterium, and Streptococcus thermophilus probiotic strains at a dose of 5 billion colony forming units (CFU) or placebo for eight weeks.
A total of 51 subjects were included, with a mix of males and females aged 18-70. Participants with serious preexisting conditions, those consuming probiotics through food or other supplements, and those on antibiotic therapy were excluded from the study.
IBS was evaluated using 2 different scoring systems for severity and overall improvement before and after treatment. All included participants presented with at least a “moderate” type of IBS according to the scoring scale.
Results showed that the probiotic-treated group experienced significant improvements in symptom severity and quality of life, as evidenced by decreased total severity scores, as compared to the placebo group. After 8 weeks, 60% of participants in the probiotic group reported score improvement from the “moderate” to “mild” category, versus 30% in the placebo group. There was no difference in the occurrence of side effects between groups.
Previous research has yielded varying results, although different probiotic strains, combinations of strains, doses, and duration of treatment were used. Thus, there are many factors to consider in studying the effects of probiotics.
This study is just one of many demonstrating the potential for probiotics in addressing IBS and other gastrointestinal disorders. It is important to note, however, that not all probiotics are created equal. Further investigation is warranted to determine which strains at which doses and for how long these microorganisms should be supplemented and what role they may sustain in different conditions.
References
- Wald, A. Clinical manifestations and diagnosis of irritable bowel syndrome in adults. UpToDate. https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-irritable-bowel-syndrome-in-adults?search=ibs&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2#H2263560866. Updated July 20, 2022. Accessed December 22, 2022.
- Skrzydło-Radomańska B, Prozorow-Król B, Cichoż-Lach H, et al. The Effectiveness and Safety of Multi-Strain Probiotic Preparation in Patients with Diarrhea-Predominant Irritable Bowel Syndrome: A Randomized Controlled Study.Nutrients. 2021;13(3):756. Published 2021 Feb 26. doi:10.3390/nu13030756.
