Science Update

New review demonstrates the role of probiotics in irritable bowel syndrome

Irritable bowel syndrome (IBS) can be a debilitating condition consisting of cramping, abdominal pain, bloating, gas, diarrhea and constipation. IBS can affect and one’s work, sleep and relationships.

A variety of factors have been associated with IBS such as genetic susceptibility, infections, small bowel intestinal overgrowth, deficiencies in tight junction proteins, intestinal abnormalities with bile acid metabolism, changes in GI motility, visceral hypersensitivity, dysregulation of the interaction between the CNS and enteric nervous system, as well as psychosocial factors. The gastrointestinal tract is considered to be the body’s ‘second brain’; it is made up of a self-contained, complex network of neurons, neurotransmitters, and proteins embedded in the lining of the GI system. It is responsible for all aspects of the digestive process, from the esophagus to the stomach and small and large intestines.

In a new review published this week, researchers investigated the effects of probiotic supplementation on IBS symptoms. Previous animal studies have demonstrated the effects of the gut microbiome on brain function and behavior as well as the influence of the brain on the composition of microbes in the gut.

This review included eleven random controlled trials within the last five years evaluating the effects of probiotic supplementation on IBS symptoms. As a result, seven studies demonstrated a significant improvement in IBS symptoms compared to placebo while the other four studies did not. It is important to note that three of the studies used a supplement containing only one probiotic strain compared to the other eight that used a multi-strain probiotic. In conclusion, the clinical benefits in IBS were seen in multi-species probiotics give over an eight-week period.

The two most common genus studied were Lactobacillus and Bifidobacterium. Previous studies have reported both increased or decreased amount of Lactobacillus and reduced amounts of Bifodobacterium in IBS patients.

A combination of botanicals, enzymes, fiber, and probiotics may be needed to optimize the gastrointestinal environment. Specific diets like the low-FODMAP diet should be considered. Certain diagnostic tests may also be beneficial, including stool testing as well as food antibody testing, as certain diets and probiotics can be personalized based on an individual's gut microbial profile.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Dale HF, Rasmussen SH, et al. Probiotics in Irritable Bowel Syndrome: An Up-to-Date Systematic Review. Sept 2, 2019. Nutrients 2019, 11(9), 2048.