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A Dietitian's Guide: Probiotics & Prebiotics in Irritable Bowel Syndrome

By Sascha McMeekin, Accredited Practising Dietitian, Owner and Principal Dietitian at Prosper Dietetics

If you are one of the 11% of the population living with the daily burden of irritable bowel syndrome (IBS) then you have probably heard of prebiotics and probiotics. You may have even tried taking them in the hope that they will be the answer to your perpetually bloated tummy, your stress about where the nearest toilet is, or the sluggishness after yet another day without a bowel movement. But before you reach for the supplements, it’s important to know the difference so you can make the right choice (or choices!) for you.

What are probiotics and prebiotics and how are they connected with IBS?

Probiotics are living micro-organisms that can have health benefits if taken in adequate quantities. You can take them in a capsule, or sachet, and they can be refrigerated or non-refrigerated. The quantity and strain of bacteria varies from brand to brand, as does the price. Dietary sources of probiotics include yoghurt, kefir and sauerkraut.

So, what matters when it comes to probiotics for IBS? A recent scientific review article concluded that probiotic supplements are beneficial for IBS symptoms if taken in the correct quantity for a suitable amount of time. In addition, research indicates that matching the strain of bacteria to your individual IBS-symptom profile may be of benefit.

Why do probiotic supplements help with IBS symptoms? There are many potential reasons for this. Primarily, it is believed one of the contributing factors to the development of IBS is having an ‘altered microbiome’ – when an individual’s gut bugs have significantly changed. Probiotics help to “restore the balance” to your gut flora and reverse IBS symptoms.

If I take probiotics for a while, will my IBS be cured?

If your IBS symptoms do improve on a particular probiotic unfortunately you will probably need to continue to take that probiotic in order to continue to experience the same symptom improvement. If your symptoms do not improve after trialing a probiotic for the recommended amount of time, it may be worth trialing a different type.


3 things to consider before your Accredited Practising Dietitian can decide the best probiotic for you:

1. Decide which IBS symptom is troubling you most.

2. Write a list of the probiotics you have tried previously (if any).

3. Consider, will you need a shelf-stable option, or could you take one that requires refrigeration?


If you don’t like the sound of taking a probiotic every day, I have good news. Did you know that you can grow your own good bacteria by eating prebiotic-rich foods?

Prebiotics are the precursors to probiotics. They act like a tree that probiotics grow on, or, if you prefer to be technical, ‘a substrate that is selectively utilized by host microorganisms conferring a health benefit’. Prebiotics are particular plant fibres that the healthy bacteria in your gut thrive on by way of a fermentation process and can be found in foods like chicory root, Jerusalem artichoke or powdered supplements.

Hang on, fermentation?! I know that an alarm bell is going off for the FODMAP savvy readers among you. Yes, prebiotics ferment in the intestines and fermentation produces gases, which can lead to the dreaded belly bloat and questions like, “When are you due?”

Luckily, not all prebiotics are linked with bloating. And it all comes down to the rate of fermentation as well as how much prebiotic-rich food you consume.

If a prebiotic is rapidly fermented, gases are produced too quickly, accumulating in your intestines before your body has a chance to move them along. This is a recipe for bloating, pain and a hot water bottle. Unless you have a small dose, that is. If a prebiotic is fermented slowly, gases are produced slowly and therefore have time to escape as long as the dose is not too big. So you get the health benefits without the bloat.

Can prebiotics improve my IBS symptoms?

Research to support the use of prebiotic supplements in treating IBS is limited at this stage. In the few studies that have been done, prebiotic supplements have failed to improve IBS symptoms. Theoretically, however, researchers remain hopeful. Prebiotics have the potential to improve IBS symptoms in a similar way to probiotics via restoration of a healthy gut microbiome (by helping to grow good bacteria) and by reducing the intestinal inflammatory response.

So if we put prebiotic supplements aside (for now) what about prebiotic-rich foods? Getting adequate prebiotics in your diet is a key component of a healthy gut. It can be especially tricky to get good sources of prebiotics if you are modifying the FODMAP content of your diet. But it can be done!


My top 5 non-bloating prebiotic foods (all ‘green’ low FODMAP serves):

1. Cooked, cooled, unpeeled potato

2. ½ cup rolled oats

3. ½ cob of sweet corn

4. ½ cup of chickpeas

5. 10 almonds



Ooi, S. L., Correa, D., & Pak, S. C. (2019). Probiotics, prebiotics, and low FODMAP diet for irritable bowel syndrome–What is the current evidence?. Complementary therapies in medicine, 43, 73-80.


Sascha is an Accredited Practising Dietitian and a Monash University certified FODMAP Dietitian. She has over 8 years of experience helping people manage IBS. Her career has included working in the research and hospital setting and has taken her across the world to leading the functional gut disorder outpatient clinics at London Bridge Hospital to being the Gastrointestinal and Colorectal Dietitian at St John of God Subiaco Hospital in Perth, Australia. Currently, alongside helping her clients in her Perth clinic and online, she is working with Nobel Laureate Professor Barry Marshall’s Noisy Guts research team at the University of Western Australia, which aims to develop a non-invasive diagnostic tool for gut disorders including IBS.

To book your free discovery call with Sascha click here

For more of the latest nutrition advice for IBS visit Sascha on Instagram @ibs.gut.dietitian

Note: Probiotics may not be suitable for the critically ill or immunocompromised individuals.


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