Changes in the gut microbiome composition are common among people dealing with Irritable Bowel Syndrome (IBS). Therapies that specifically target gut bacteria are a promising solution for relieving symptoms of the disease.

By Maria Arvaniti  Irritable Bowel Syndrome (IBS) is a complex and rather painful digestive disease. If you suffer from IBS, you‘re definitely not alone: 1 out of 9 people are currently diagnosed with this disease, which adds up to approximately 847 million people1! What is interesting though – and also a little frustrating – is that not everyone has the same experience with this condition. What triggers IBS seems to be very individual. However, researchers have discovered that changes in the composition of the gut microbiome may be the common ground.

What changes in IBS

Scientist got a hint of the involvement of gut microbes when they figured out that people who took systemic antibiotics were at 3 times higher risk of developing IBS. Looking into the composition of the gut microbiota, IBS patients seem to have significantly less Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii 2. All these are common beneficial bacteria found in the guts of healthy people.

IBS patients seem to have significantly less Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii 

So what happens when these beneficial bacteria are lacking from our guts? Research has shown that this could bring changes in the permeability and motility of our intestines. What’s more is that it can also affect how we process food. Unfortunately, these changes might turn our gut into a hypersensitive organ that reacts strongly to food that would otherwise be easily digested.

Microbiome-based therapies

Luckily, the involvement of gut bacteria in IBS gives scientists the opportunity to develop new treatment strategies3. Below, you can find a list with the most important, recent IBS therapies that target your gut microbiota:

– Rifaximin: This is an antibiotic used for the treatment of adults with IBS-D (IBS with diarrhea). It targets Gram-positive and Gram-negative bacteria and it has been shown to modulate the signals our gut sends to our immune system. In some patients, this antibiotic led to eradication of SIBO, which is also a common condition, often co-occurring with IBS4.

– Prebiotics: These are ingested compounds that are known to stimulate the beneficial gut microbiota. They are thought to have anti-inflammatory effects and they prevent “bad” bacteria from infecting our intestines.

– Probiotics: Here, we are talking about microorganisms, such as bacteria, that can be taken orally. They have beneficial effects on our health and, just like prebiotics, they protect us from pathogenic microorganisms, keep our intestines intact and boost the production of beneficial nutrients.

– Serum-derived bovine immunoglobulin (SBI): SBI is a US Food and Drug Administration-approved medical food, recommended to patients with IBS-D. There is very little evidence on its actions, but it is thought to help maintain a normal gut microbiota and decrease the permeability of our intestines.

– Dietary modification: A more natural way of managing your IBS is by changing your dietary habits. Importantly, it is highly recommended to avoid foods that you suspect might cause you irritation. Lately, the low FODMAP diet seems to be a good option for treating IBS. FODMAPs are short-chain, highly fermentable carbohydrates. They are not absorbed well by our gut, but rather they are rapidly fermented by gut bacteria. A downside is that they increase the amount of fluids in our gut, promoting the contraction of our intestines, and thus causing discomfort. Therefore, avoiding food high in FODMAPs might help ease your IBS symptoms.

Since IBS is very individual among people, what works for one might not work for others. So, a close look into your gut – mainly into what lives in there – as well as experimenting with different dietary interventions, can help you find out what solution works best for you and your gut!


  1. Lovell, R. M. & Ford, A. C. Global Prevalence of and Risk Factors for Irritable Bowel Syndrome: A Meta-analysis. Clin. Gastroenterol. Hepatol. 10, 712–721.e4 (2012).
  2. Liu, H.-N. et al. Altered molecular signature of intestinal microbiota in irritable bowel syndrome patients compared with healthy controls: A systematic review and meta-analysis. Dig. Liver Dis. 49, 331–337 (2017).
  3. Stern, E. K. & Brenner, D. M. Gut Microbiota-Based Therapies for Irritable Bowel Syndrome. Clin. Transl. Gastroenterol. 9, e134 (2018).
  4. Giamarellos-Bourboulis, E. J., Pyleris, E., Barbatzas, C., Pistiki, A. & Pimentel, M. Small intestinal bacterial overgrowth is associated with irritable bowel syndrome and is independent of proton pump inhibitor usage. BMC Gastroenterol. 16, 67 (2016).