The Role Of The Microbiome, Probiotics And FODMAPs

The Role Of The Microbiome, Probiotics And FODMAPs

The gut microbiome has been implicated in nearly all health and disease models in industrialized society, including IBS. But should this come as a surprise?

You have trillions of bacteria living in your digestive tract. That’s more than the number of human cells that make up your whole body, and even more microbes than there are stars in the milky way! The genes in your microbiome outnumber the genes in your genome 150:1, and it is thought that as much as 90% of diseases can be linked in some way back to the gut and the health of the microbiome.


Each individual has a unique gut microbiota, as personal as a fingerprint. It can be influenced by your genetics, diet, medications, ethnicity, and even your birth route. There is also a communication between your gut and brain, highly influenced by the microbes that reside.

And those who know me, know that the gut microbiome is one of my favourite subject areas. From my early academic career in immunology and microbiology, to my later trainings in nutrition and dietetics – I have come to appreciate the complexity of the gut microbiome in spanning multiple human biology disciplines. I believe that, despite significant progress, we are still in the early stages of understanding the microbiome.

Only recently has the research and medical community taken a closer look at the microbiome’s role in health and disease. Research publications have grown exponentially since the early 2000s, including exciting research on the characterization and management of IBS.

IBS and the Gut Microbiome

IBS is the most common functional digestive condition in the industrialized world. It is well accepted that your gut microbiome plays a central role in the symptoms that characterize IBS

Research has shown that specific bacteria have been associated with microbiomes of IBS patients. Interesting questions that remain include if these microbial “fingerprints” are a product or a cause of IBS.

Dysbiosis in IBS

Normally, gut bacteria contribute to your health in a mutually beneficial relationship. You provide them with nutrients such as prebiotic fibres. They provide many factors that regulate your body’s physiology. They also can act as a protective barrier to harmful bacteria. But the dynamic ecosystem that houses the gut microbiome has many interdependent relationships. The health of your immune system, your dietary patterns, medications, and even your stress levels can impact gut health. When disruptions occur, this can lead to something called dysbiosis.

Manage IBS

A systematic review and meta-analysis of case-controlled studies concluded that IBS can be characterized by gut microbial dysbiosis. Compared to non-IBS sufferers, we see differences in the amounts and types of certain bacteria, which contribute to a range of digestive symptoms including abdominal discomfort, bloating, constipation and/or diarrhea.

The Gut-Brain Axis and Stress

Current research has identified a strong communication link between the brain and the digestive system. This bi-directional communication has been shown to impact the health of your central nervous, gastrointestinal, and immune system. Interestingly, the health ofyour intestinal bacteria is linked to depression, mood, and anxiety. More research is needed but the practice of mindfulness is non-invasive and generally regarded as beneficial in health and disease.

In addition to foods that contribute to a healthy digestive system, I highly recommend a practicing mindfulness-based stress reduction (MBSR) to assist in managing symptoms. For example, you can include a mindful activity each day such as meditation, tai chi, qigong, mindful walking, or even doing daily chores mindfully. You can also try setting aside time to eat your meals in a relaxed, mindful manner. 

Interestingly, mindfulness originated from Buddhism practices, but it’s implementation and iterations in research, culture, and daily life have expanded greatly over the years.  I learned about MBSR during my training as a dietitian, and also about mindfulness and meditation through my training as a yoga teacher. I believe mindfulness is a practice unique to the individual, but I can certainly be a resource if you would like to learn more.

Probiotics and Supplements

Probiotics are live bacteria in supplement form that can be taken to assist in various aspects of health, including digestive health. In contrast, fermented foods also contain live (typically) beneficial bacteria). Probiotic therapy may be helpful in relieving symptoms of IBS.

Some examples of probiotics used in IBS treatment include: Gut-FX Formula, Align, Renew Life Ultimate Flora, VSL #3, and HMF Forte. Peppermint oil taken as a supplement has also been shown to provide some relief in IBS. A product I recommend to try would be IBgard.

FODMAPs and the Low FODMAP Diet

Many people with IBS are sensitive to small fermentable carbohydrates known as Fodmap’s (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols).

Fodmaps are simply categories of carbohydrate types that, in sensitive individuals, are poorly absorbed in the small intestine of the digestive tract. They then continue their journey to the large intestine, where they act as a food source to the bacteria that live there. The fermentation of one or more of the fodmaps by your gut bacteria can cause symptoms of IBS.


IBS sufferers may benefit from reducing fodmaps in their diet. However, there are six types of FODMAP’s and it is likely that the individual is not sensitive to all.

There is much misinformation on the web regarding the low fodmap diet, and even appropriate information can seem confusing without support. Additionally, the low fodmap diet is not meant to be long term, as it can also lead to some nutrient deficiency when there is long term restriction. For example, getting enough fibre on a low FODMAP diet can be challenging without proper guidance, which may also impact the health of your gut microbiome.

If you would like to try the low fodmap strategy, I highly recommend reviewing this approach together before starting. Its success is highly dependent on proper education, planning, and support.

Further FODMAP Resources

Monash University in Australia is where the original research on low FODMAP was done. The MONASH University FODMAP app is an excellent resource to help strategize a plan to reduce symptoms and identify food triggers.

Kate Scarlata RDN LDN is a leading expert in the field of IBS and low FODMAP living. Her website – katescarlata.com – is full of excellent resources.


The health of the microbiome is implicated in IBS, with several strategies available for treatment of symptoms. Examples include: probiotic therapy, mindful-based stress reduction, and low FODMAP strategy to identify food triggers. Food intolerance tests are not validated by science, and should be avoided. 

I am here to help and answer questions along the way, so please book an appointment or contact me if you have questions, concerns, require support or want ideas. I look forward to working with you.

Dan Neuman
Registered Dietitian 

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