Thursday, August 25, 2016

Probiotics and Irritable Bowel Syndrome

This past April, I presented my research with Dr. Suzanne Neubauer on Treatment of Irritable Bowel Syndrome with Probiotics at the Massachusetts Dietetic Association's Annual Nutrition Convention and Exposition. This research was a part of the Seminar in Clinical Nutrition course that I took in Framingham State University's Coordinated Program in Dietetics. Below is a summary of my findings.

Presenting Treatment of Irritable Bowel Syndrome with Probiotics at MDA's ANCE
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain or discomfort and abnormal bowel habits, with an estimated global prevalence of 11%. It has unclear causes and is diagnosed based on symptoms rather than structural abnormalities. Probiotic supplementation has been proposed to treat IBS, because the fecal microbiota composition of patients with IBS has been found to be significantly different compared to healthy patients. 

A review of 21 primary studies was performed to examine the efficacy of probiotic treatment on IBS symptoms in subjects over 16 years old. Most of the studies reviewed were double-blind, placebo-controlled, randomized controlled trials. While some trials examined multi-strain probiotics, others assessed the influence of individual probiotic strains.

The results suggest abdominal pain, bloating, stool frequency, stool consistency, adequate relief, and quality of life are not adequately addressed with multi-strain probiotics in patients with all types of IBS. Different dosages, compositions of probiotic mixtures, treatment lengths, and subtypes of IBS studied make trials on probiotics hard to compare. The results were also impacted by the placebo effect, which may be a common occurrence in IBS trials, because IBS has unclear etiologies and is diagnosed based on subjective report of symptoms. 

Meanwhile, impacts of single strains of Escherichia, Bifidobacterium, Saccharomyces, and Lactobacillus were limited and varied according to specific strains. Drawing general conclusions from the studies on single-strain probiotics is not straightforward, as outcomes were strain specific, and some results were only observed in one bacterial strain in one trial.

Due to the inadequate number of studies that demonstrate substantial benefits of probiotics, single- and multi-strain probiotic supplements are not recommended for IBS treatment. However, if patients with IBS are interested, taking up to 8 strains of probiotics and up to 9x10^11 CFU per day has been shown to be safe.

I was surprised to discover there was not enough evidence to support supplementing with probiotics to treat IBS. However, following a low-FODMAP diet may help to manage IBS symptoms. In addition, find out what else probiotics may be good for at the Boston Fermentation Festival this Sunday!

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