Anxiety, IBS and Microbiome Links

gut brain

Dakota Rhys-Jones - Research Dietitian, 29 January 2020

 IBS, quality of life & mental health 

As we know, irritable bowel syndrome can bring many unwanted symptoms for those one in seven that live with the condition. People with IBS experience diarrhoea, abdominal bloating, pain, wind etc. and this can bring anxiety and a significantly decreased quality of life. Those living with IBS report increased absenteeism from work, more days spent in bed, their relationships are affected, as well as activities such as dining out (1).

Increasingly, we are seeing a link between the gut and the brain; people often speak about the gut being a ‘second brain’ where they are referring to the gut-brain axis. This term defines the bi-directional flow of information that occurs between the brain and the gut, meaning that signals from the brain can have an impact on the gut and vice versa (2).  In short, individuals’ symptoms may increase their stress or anxiety, or, stressful situations may exacerbate their symptoms. It therefore makes sense that in the IBS population, psychological disorders such as anxiety and depression are more common (3).

 FODMAP diet & adjunct therapies to improve symptoms, quality of life & mental health

So where to for someone with stress or anxiety, as well as IBS? Do we control our stress or do we control our symptoms or can we combat both at once? We know that approximately ¾ of people who go on a low FODMAP diet will experience controlled symptoms, which in turn improves their stress levels and quality of life. As an adjunct to the low FODMAP diet, there is increasing evidence for gut-directed hypnotherapy to improve IBS symptoms. One of our studies looked at the low FODMAP diet, gut-directed hypnotherapy, and a combination of both on its effects on symptoms as well as psychological indices (4). All forms of treatment were beneficial; however, the combination diet and hypnotherapy led to greater improvements in the psychological areas. Here, we have a case for the use of both forms of treatment for some individuals with IBS.

Microbiome links 

How does the microbiota fit into all of this? Although research is still trying to define a ‘healthy microbiome’, (5) we are seeing more evidence supporting that the microbiome in people with IBS is different to otherwise healthy individuals (6). Similarly, gut dysfunction and ‘dysbiosis’ can be seen in animal models of stress, anxiety and depression (7). Again, we have a situation where it is like the ‘chicken or the egg’ between gut and brain, and researchers are working hard to explain where the microbiome fits into all of this. Fortunately, research and technology are evolving at such a rapid pace, that we may have some answers to these rather interesting and challenging concepts sooner, rather than later!



1.        Hungin AP, Whorwell PJ, Tack J, Mearin F. The prevalence, patterns and impact of irritable bowel syndrome: an international survey of 40,000 subjects. Aliment Pharmacol Ther. 2003;17(5):643-50.

2.        Mayer EA, Savidge T, Shulman RJ. Brain–Gut Microbiome Interactions and Functional Bowel Disorders. Gastroenterology. 2014;146(6):1500-12.

3.        Pinto-Sanchez IM, Ford CA, Avila AC, Verdu FE, Collins MS, Morgan MD, et al. Anxiety and Depression Increase in a Stepwise Manner in Parallel With Multiple FGIDs and Symptom Severity and Frequency. American Journal of Gastroenterology. 2015;110(7):1038-48.

4.        Peters SL, Yao CK, Philpott H, Yelland GW, Muir JG, Gibson PR. Randomised clinical trial: the efficacy of gut-directed hypnotherapy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome. Alimentary Pharmacology & Therapeutics. 2016;44(5):447-59.

5.        Clemente Jose C, Ursell Luke K, Parfrey Laura W, Knight R. The Impact of the Gut Microbiota on Human Health: An Integrative View. Cell. 2012;148(6):1258-70.

6.        Pittayanon R, Lau JT, Yuan Y, Leontiadis GI, Tse F, Surette M, et al. Gut Microbiota in Patients With Irritable Bowel Syndrome—A Systematic Review. Gastroenterology. 2019;157(1):97-108.

7.        De Palma G, Collins SM, Bercik P, Verdu EF. The microbiota–gut–brain axis in gastrointestinal disorders: stressed bugs, stressed brain or both? The Journal of Physiology. 2014;592(14):2989-97.

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