IBS has many causes-including when it is a misdiagnosis for another condition. It can be triggered by diet, which is why some find the low FODMAP diet helpful or flare-up during stress. However, some people find that it is actually developed after a bout of food poisoning, and it’s now possible to pinpoint this to post-infectious IBS. I spoke to Marilia, from Gutfulness Nutrition who specialises in this area of IBS to learn more about this type of IBS.
What is post-infectious IBS?
Post-Infectious IBS is a type of IBS that is caused by food poisoning. Although not much is talked about, 1
in every 9 people who experience food poisoning happens to develop Post-Infectious IBS up to six months
after the initial bacterial infection. This may have similar symptoms to those with IBS but a different cause.
What causes post-infectious IBS?
The most common bacteria that cause food poisoning release a toxin called Cytolethal Distending Toxin B
(CdtB). When CdtB enters the body, the immune system fights back with an antibody called anti-CdtB.
Due to molecular similarities, CdtB can look similar to vinculin, a naturally occurring protein in the body
that is critical for proper gut function. Because of this similarity, the immune system gets confused and
thinks it needs to fight back against vinculin and starts to produce another antibody, called anti-vinculin.
The production of anti-vinculin antibodies leads to gut nerve damage and improper functioning of the
The interstitial cells of Cajal (ICC) and the Migrating Motor Complex (MMC), and both play a critical role in gut
motility. When gut motility is impaired, the gut microbiome is consequently disrupted leading to all sorts of
digestive symptoms such as bloating and alternated bowel movements.
Another consequence of a disrupted gut microbiome is increased visceral hypersensitivity – a hallmark of IBS symptoms – which alters the gut-brain axis communication and increases brain response to abdominal pain.
How do people know if they have post-infectious IBS?
There is a test that can be done. Firstly, post-infectious IBS almost always has a diarrhoeal component, a common symptom of traveller’s diarrhea and gastroenteritis; so it’s not common for IBS-C. but is if you have IBS-D or IBS-M. If you feel your symptoms started after picking up a bug, you could have post-infectious IBS and it could be a place to start.
Until recently IBS was a diagnosis of exclusion, meaning that GPs and specialists would rule out any
medical condition such as Inflammatory Bowel Disease, Coeliac Disease and most recently
Endometriosis, before concluding your digestive symptoms are caused by IBS. However, Post-infectious
IBS is the only form of IBS that has a valid diagnosis test called IBS Smart – a blood test developed in the
USA by world-leading IBS researcher Dr. Mark Pimentel that measures the levels of two validated IBS
biomarkers, anti-CdtB and anti-vinculin, providing a positive or negative result.
That of course does not mean you should not rule out other medical conditions and other potential triggers for your IBS symptoms but it can be a good way to pinpoint the cause of your IBS.
At the moment IBS Smart can only be ordered via a licensed practitioner; such as a dietician or nutritionist.
How can you treat post-infectious IBS?
Unfortunately, treating post-infectious IBS isn’t necessarily more straightforward than other types of IBS; but it can help narrow down treatments that are likely to be more helpful-for example, if you know you have post-infectious IBS, stress may be less of a trigger. One study concludes that no therapies are proven to be effective specifically for the management of PI-IBS but looking at IBS treatments can help.
According to IBS smart, typical treatments can also include the low FODMAP diet, as well as things like probiotics or even a faecal transplants (although these are rarely done in the UK).If you think you may have post-infectious IBS, an expert such as Marilla (@gutfulnessnutrition) or any qualified nutritionist or dietician may be able to support you.
Post-Infectious IBS is an important and often overlooked condition that can develop after food poisoning. Understanding its distinct cause, linked to immune response and gut motility disruption, can help those affected better manage their symptoms. It’s encouraging that diagnostic tests like IBS Smart are now available to pinpoint this specific type of IBS, offering a clearer path for treatment and management strategies tailored to post-infectious IBS.