Do Probiotics Help With Irritable Bowel Syndrome?

Check out this answer from Consensus:

The current evidence suggests that probiotics can be effective in improving IBS symptoms, particularly when multi-strain supplements are used. Probiotics appear to be safe for most patients, although more research is needed to identify the most effective strains and combinations. Given the variability in individual responses, personalized approaches to probiotic therapy may be beneficial for IBS patients.

Irritable Bowel Syndrome (IBS) is a common functional gastrointestinal disorder characterized by symptoms such as abdominal pain, bloating, and altered bowel habits. The exact cause of IBS is not well understood, but alterations in the gut microbiota have been implicated. Probiotics, which are live microorganisms that confer health benefits to the host, have been proposed as a potential treatment for IBS. This article reviews the current evidence on the efficacy of probiotics in managing IBS symptoms.

Mechanisms of Probiotics in IBS

Probiotics are thought to improve IBS symptoms by modulating the gut microbiota, enhancing the gut barrier function, and exerting anti-inflammatory effects. However, the exact mechanisms remain unclear and may vary depending on the specific strains and combinations of probiotics used1 6.

Efficacy of Probiotics in IBS

Systematic Reviews and Meta-Analyses

Several systematic reviews and meta-analyses have evaluated the efficacy of probiotics in IBS. A systematic review of 35 randomized controlled trials (RCTs) found that probiotics significantly improved IBS symptoms compared to placebo, with multi-strain probiotics showing more distinct benefits1. Another meta-analysis involving 3,452 patients reported that probiotics reduced the persistence of IBS symptoms and improved global symptoms, abdominal pain, bloating, and flatulence scores3.

Specific Strains and Combinations

The effectiveness of probiotics may depend on the specific strains and combinations used. For instance, a study on Bifidobacterium longum NCC3001 found that it reduced depression scores and improved quality of life in IBS patients, although it did not significantly affect IBS symptoms2. Multi-strain probiotics have generally shown more consistent benefits compared to mono-strain supplements1 3.

Constipation-Predominant IBS

Probiotics have also been studied in patients with constipation-predominant IBS (IBS-C). A meta-analysis of 17 RCTs found that probiotics significantly increased stool frequency, improved stool consistency, and shortened gut transit time in IBS-C patients5. Another review confirmed these findings, highlighting the safety and potential benefits of probiotics in improving stool consistency and increasing beneficial gut bacteria10.

Safety of Probiotics

While probiotics are generally considered safe, some studies have reported a higher incidence of adverse events compared to placebo. However, these adverse events are typically mild and self-limiting3 10. More high-quality studies are needed to better understand the safety profile of different probiotic strains and combinations.

 

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Do probiotics help with Irritable Bowel Syndrome?

Emma Allen-Vercoe has answered Unlikely

An expert from University of Guelph in Microbiology, Microbiome

I have answered ‘unlikely’ because I don’t think that ‘probiotics’ can be lumped together as a group. Everyone has a different gut microbiome, and thus there is no one-size-fits-all probiotic treatment.

For IBS, repeated studies have failed to find any convincing differences in the gut microbiota compared to the healthy population, though many of these studies looked at composition (which microbes are there?) only. The jury is still out on functional difference (i.e. what are the microbes doing?).

The idea that there is ‘dysbiosis’ in IBS is problematic because there is no definition for dysbiosis as yet, because everyone has a different gut microbiome and it is still unclear what ‘normal’ looks like. Thus, until we can understand the cause of IBS, we are unlikely to be able to fix the problem.

Probiotic administration represents a low risk strategy that some people find helpful for managing symptoms, however the reported benefits are usually moderate and could potentially be a placebo effect. One has to be very wary, too, about the very many poorly produced probiotic preparations that are for sale. There are a few probiotic strains for which the data in support of a beneficial effect in IBS are very good, but the reason I voted ‘unlikely’ is that such valid probiotic preparations are a minority in this landscape.

In short, with very variable disease states in IBS (it is an umbrella term for a range of syndromes), the variable microbiomes of patients, the varied probiotic strains available and the variable manufacturing standards of these preparations (which are largely sold as food supplements and not drugs) , it is no wonder that the scientific waters around this topic remain murky.

What is needed is a more systematic approach to studying the function of the gut microbiota in IBS, and, in turn, the IBS needs to be stratified by type because it is a spectrum of disorders rather than a single disease.

 

Do probiotics help with Irritable Bowel Syndrome?

Tomislav Meštrović has answered Likely

An expert from University North in Microbiology, Public Health

There is at least a hypothetical benefit of using probiotics in irritable bowel syndrome (IBS), for example via reducing counts of Proteobacteria and agonistic LPS concentration, ameliorating in turn certain motility disturbances pertinent to this condition. However, the intricate interplay between microbial, genetic and environmental factors is presumably responsible for the phenotypic heterogeneity found in IBS, thus the successful treatment of different disease subsets may require specific and targeted microbial manipulations. In a nutshell, it is quite hard to provide specific recommendations for IBS management when probiotics are concerned; nonetheless, if we analyse various probiotic features such as single vs multi-strain trials and concentration (CFU/day), it may be possible to utilize current data to make some informed choices.

 

Do probiotics help with Irritable Bowel Syndrome?

Mahmoud Ghannoum has answered Likely

An expert from Case Western Reserve University in Microbiology, Medicine

An underlying reason contributing to IBD is an imbalance in the microbiome. Thus, approaches that can rebalance and maintain the microbiome in IBD patients represent potential ways to achieve this. Animal studies and limited human trials indicate that probiotics may have utility as adjunct therapy with anti-inflammatory agents such as mesalazine in the treatment of IBD(Source).

A number of underlying mechanisms have been suggested for how probiotics can help in IBD (e.g. reducing intestinal inflammation). The published literature also suggest that a single probiotic strain is unlikely to be equally effective in all patients. Although available data regarding the role of probiotics in the treatment of IBD are promising, more clinical studies are needed.

So my answer is ‘likely’, especially when using more than one strain to ensure effectiveness.

 

Do probiotics help with Irritable Bowel Syndrome?

Arthur C Ouwehand has answered Likely

An expert from DuPont Nutrition and Health in Microbiology

IBS is a diverse condition, with subjects experiencing constipation, diarrhoea or both. It may well be that these have different underlying aetiologies. Nevertheless, there does seem to be an overall benefit of probiotics although it often is rather modest. This is among others due to the substantial placebo effect commonly observed in IBS studies.

 

Do probiotics help with Irritable Bowel Syndrome?

Tom MacDonald has answered Unlikely

An expert from Queen Mary University of London in Immunology, Gastroenterology

This literature is a pile of garbage. IBS comes in 2 forms, constipation, diarrhoea and alternating constipation/diarrhoea. It has no reliable readouts apart from symptom scores and there is a huge placebo rate in trials.

To understand why this stuff gets published, it is because there is a bunch of gastroenterologists who make a living out of IBS and who review each others paper and invite each other to meetings. There is also a big problem that different studies use different probiotic bacteria or combinations so to do a meta-analysis you need to stick to the same probiotic, but frequently dosing is different between studies. The only thing that can be said is that if taking a probiotic helps folk with IBS, then carry on, it will do no harm. Meta-analysis shows either no effect or small positive effects.

 

Do probiotics help with Irritable Bowel Syndrome?

Donatella Verbanac has answered Uncertain

An expert from University of Zagreb in Biochemistry, Pharmaceutics, Medicine, Education

When probiotics (Bifidobacterium and Lactobacillus)  were taken in combination with digestive enzymes twice/three times daily, the symptoms of IBS were less severe (almost rare) in people suffering of IBS. However, this is based on personal experience that represents an uncontrolled observation for longer period of time (3-6 months) and cannot be used to draw any conclusive answer yet.

 

Do probiotics help with Irritable Bowel Syndrome?

Michael Schultz has answered Likely

An expert from University of Otago in Gastroenterology

In certain cases, for instance in post-infectious IBS or any other instance where dysbiosis is suspected, probiotics have a place. I also recommend probiotics prior to travelling to avoid travellers diarrhoea that can lead to post-infectious IBS.

 

Do probiotics help with Irritable Bowel Syndrome?

Raquel Abalo has answered Likely

An expert from King Juan Carlos University in Gastroenterology, Pharmacology, Nutrition

There are recent evidences in the scientific literature that probiotics may exert important roles to keep the gut in healthy conditions. It is generally believed that these microbes are helpful to keep pathogens at low numbers and traditional diets including fermented dairy (yoghurt, cheese) are acknowledged for their beneficial effects in the context of diarrhea. IBS has been associated to dysbiosis and therefore the use of probiotics may normalize microbiota and reduce IBS symptoms, particularly in case of diarrhea. But different types of IBS do exist and the possible effect of probiotics to alleviate (or prevent) IBS with constipation is less clear. Like in other scenarios, evidences from preclinical studies (in which conditions are more easily controlled) seem overwhelming to suggest that certain strains of bacteria (or their combinations) are actually useful to treat IBS. However, clinical studies do not offer such certainty in most cases; some times, the effects are only minor. We need more time, money and well-designed clinical trials to give a definite answer to the question.

 

Do probiotics help with Irritable Bowel Syndrome?

Tom Van de Wiele has answered Likely

An expert from Ghent University in Microbiology, Ecology, Biotechnology

several reports on randomized clinical trials available in literature. Yet , success is highly dependent on applied strain and significant interindividual variability is noted. Overall, encouraging data are available which could support the use of probiotics in IBS. Caution is however warranted in conditions where gut barrier integrity may be an issue.