Blog Post

Are Probiotics Helpful for IBS?

Probiotics and IBS

Probiotics are an option that can be utilised to help manage and improve the symptoms of irritable bowel syndrome (IBS).

There is evidence that they can help with improving symptoms of bloating, diarrhea, constipation, and other aspects of IBS.

Research is mixed on how effective they are. Sometimes they help, and sometimes they do not. There are a lot of different types of probiotics. And there are a lot of different types and causes of IBS.

This post will cover the research on this topic while also providing some practical recommendations.

How/Why Could Probiotics Help

Probiotics are defined as “live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host.”

To be classified as a probiotic something needs to have evidence it can confer a benefit. But that definition is often used loosely. And it also does not mean that each specific strain will help each form of IBS specifically.

Types of IBS Chart

In terms of how probiotics could help, the list is includes things such as:

  • Increasing bacteria in the large intestine that are associated with reduced symptoms.
  • Decreasing the number of pathogenic bacteria that can contribute to symptoms.
  • Influencing gut-motility.
  • Helping to manage Small intestinal bacterial overgrowth (SIBO). A lot of people with IBS also have SIBO.
  • Influencing the gut-brain axis.
  • Improving the barrier function of the endothelium.
  • Decreasing the hypersensitivity that is associated with pain from IBS.
  • Secreting short-chain fatty acids such as butyrate, which has other benefits.

There is a long list of potential benefits beyond that. I have intentionally left out the more complex mechanisms because:

  1. I want to keep this easy to read.
  2. We care more about outcomes than mechanisms. Most of the scientific reviews on this topic have concluded that they are not necessarily sure how probiotics are working. It is likely a combination of factors.

While knowing the mechanisms is great, it is only useful in situations where the probiotics improve symptoms.

What Does the Research Show?

A 2014 meta-analysis of over 30 studies found that probiotics improve symptoms of IBS on average.

Not all studies have positive findings though. A review in 2016 from the British Dietetic Association (BDA) demonstrated this well.

British Dietetic Association

Of the 29 studies they assessed, 14 of them showed a positive result. That means just under 50% had a benefit.

And within those studies, the positive results are not also consistent. One of the most promising ones involved L. Plantarum 299v and found that 78% of patients scored the probiotic as good or excellent for improving symptoms. This still means that 22% did not notice a difference.

Another example of effectiveness I wanted to share was a trial done on Bifidobacterium bifidum MIMBb75. It significantly improved IBS symptoms including abdominal pain, bloating and faecal urgency.

Adequate relief of symptoms was reported by 47% of patients in the intervention group and 11% in the placebo group. That is promising. But it also means 53% of people still had significant symptoms.

Noticeable improvements were found in 57% of people in the bifidobacteria group. So even quite a few people who did not get adequate relief still found improvements.

The most recent systematic review on the topic came out in 2022. It had similar findings but proposed that probiotics including a sufficient amount of Bacillus Coagulans had the highest probability of helping overall IBS symptoms.

What/How to Use?

Prior to diving into the research on probiotics many years ago, I wondered why it was rare to see professionals make specific recommendations. I understand it now though.

One explanation I have is that in addition to the research being relatively weak, it is also very broad.

For example, that BDA review from 2016 found that 14 of 29 studies had positive results. Of those 14 studies, 10 different probiotics were used.

Most probiotics that had positive outcomes only had one study on them showing these outcomes. That leaves a lot to be desired. It is hard to make definitive recommendations based on that.

Some basic things to look for are:

  1. Make sure that the colony forming units (CFU) count is at least 1 billion CFU per serving.
  2. Make sure it contains some of the strains mentioned so far, or other ones studied for IBS such as Lactobacillus plantarum, Lactobacillus acidophilus, and Bifidobacterium infantis.

Since it depends on what type of IBS it, I encourage checking out this great post from Healthline which covers the different types of probiotics to use for different cases.

Then use it daily. It can take 3-4 weeks to notice a difference in some cases.

The current consensus is to trial a product for 12 weeks. If it does not show benefits in that timeframe, discontinue it.

It also unfortunately appears as though the benefits from probiotics often are not long term. They might stop being beneficial within a few days of discontinuation. If you find one that works, you might want to stick with it for as long as is relevant.

Some Interesting Thoughts on the Microbiome

People with IBS typically have significantly lower levels of Lactobacillus and Bifidobacterium in their guts.

They also have higher levels of Streptococcus, Clostridium and E. Coli on average.

And while there is a range of estimates, it appears that ~30% of people with IBS have SIBO.

There is a strong association between Bifidobacterium and pain too. Those with IBS who experience pain typically have 5x fewer Bifidobacterium than those without pain.


Stats like that stand out to me. Because if you dug deep enough, you could find a LOT of those kinds of statistics for various forms and symptoms of IBS.

When you look at it from that perspective, it leads to a lot of simple questions. Does supplementing Bifidobacterium in that case help manage symptoms in those who experience pain?

This can be part of an explanation as to why probiotics featuring that species are often linked with improved symptoms.

At this stage though, that line of thinking raises a lot more questions than answers, since there is a lot more research to be done. But it does make this an exciting area since there is a lot of potential for breakthroughs in relation to more targeted therapies.

Probiotics and FODMAPs

Stages of the low FODMAP diet

One of the most common dietary approaches to manage IBS is the low-FODMAP diet.

It has a great track record of helping to improve symptoms. There are certain downsides associated with it though.

One of these proposed downsides is that on average, it leads to a reduction in Bifidobacterium. It could also increase bacteria associated with dysbiosis too. These things are already associated with IBS.

So even though the low-FODMAP diet improves symptoms, this is an area for concern.

A way around this issue that is being explored is to take probiotics alongside the diet.

Research from King’s College London found that this strategy can potentially offset these changes.

Practical Summary

While the research on probiotics looks confusing, the current consensus is simple.

Probiotics help manage IBS symptoms on average. The amount they help may not be large, and it may not be consistent.

The gold standard approach is to try a probiotic supplement for 12 weeks. If it helps, that is great, continue using it. If it does not help, either discontinue or try a different product.

Ideally, you use a product that has strains that have been linked with improved symptoms of IBS.

Since there are so many causes and types of IBS, this can be confusing. Instead of listing off all the different options, I would encourage checking out this post from Healthline. Then jump to each section that is relevant for you and look for what strains to look for in the products you are considering purchasing.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.