Ep.10 How that dodgy takeaway years ago caused post infectious IBS
24 Jul, 2023

Episode Intro

Have you ever had food poisoning? Maybe you spent a night on holiday with a dodgy tummy and kept running to the bathroom with diarrhoea all week. Or maybe a bad local takeaway left you vomiting all night. And now, five years on, you've got regular IBS symptoms like abdominal pain, gas, bloating and erratic bowel habits. If this is you, you could have post infectious IBS. It might have led to an overgrowth of microbes in your small intestine called SIBO. Post infectious IBS is one of the most common causes of IBS, and we don't know exactly how it causes your symptoms, but in this episode of the Inside Knowledge podcast, I'll share everything that you need to know about post infectious IBS so you can start to tackle your gut symptoms.

Podcast transcript

Hello and welcome to episode 10 of the Inside Knowledge for People with IBS. I’m Anna Mapson.

Today, I would like to talk to you about post infectious IBS and how some of the symptoms that you’re getting can start after an incident of food poisoning or a gastro bug, like a tummy bug. It’s quite a common cause of IBS and it’s thought that between something like five and thirty percent of people who have IBS, this was their trigger.

How could food poisoning affect IBS?

It happens where your gut’s nervous system or the mucous lining becomes damaged as your body is trying to get rid of a pathogen. So it starts with us eating something bad and kicks off to these long lasting symptoms.

Some people that I work with have really clear memory of an episode of food poisoning that they know triggered their symptoms.

Other people might just think, “Oh, I did have that food poisoning once. Or, you know, there was an episode where I got stomach bug and had diarrhoea, vomiting, and then actually, yeah, my symptoms did start. after that.”

IBS can start from all kinds of causes and triggers, so it’s just one potential cause of your IBS.


The symptoms of post infectious IBS are very similar to other kinds of IBS, but typically people get a lot more abdominal pain, tends to be more diarrhoea rather than constipation predominant IBS. Lots of bloating and gas, like feelings of rushing to the toilet and maybe seeing mucus in the toilet.

Those kinds of things can be common to any kind of IBS, but specifically tend to be, um, really common with post infectious IBS as well.

How do you get post infectious IBS?

There’s different sort of research about who is most likely to get post infectious IBS. But some studies have shown that one in ten people will go on to develop IBS after getting a stomach bug of some kind.

It is about a four fold increased risk of getting IBS compared to people who have not had a stomach infection. The main pathogens that go on to be implicated in post infectious IBS include:

  • Campylobacto jejuni,
  • Salmonella,
  • Shigella, and E. coli,
  • Norovirus,
  • Giardia Lamblia.

These are all quite common, often food or waterborne pathogens that you can come across in a range of different places around the world. And also different types of food preparation errors that could lead you to eat something that was infected with these bugs.

Who gets post infectious IBS?

It tends to be

  • people who experience the worst kind of acute infection, who go on to get a more serious post infectious IBS.
  • Women are more likely to get post infectious IBS, but women are more likely to get IBS anyway.
  • The more serious psychological distress, interestingly, has been linked to your likelihood to get long lasting IBS. So the more distressed and upset you are by the acute infection. The more likely you are to potentially have IBS later. 

When does it start?

Why would an acute infection that your body resolves lead to implicated gut problems down the line? Because it might be that you recover and you’re fine for six months.

And only then does your IBS start. So it’s not that it would go on and on and on from the point of acute infection. It could be that you recover, you feel better for up to a year. And then even two years down the line, it’s been shown post infectious IBS symptoms can start and be triggered by that one episode.

1. Food poisoning could damage the migrating motor complex

So there is these two mechanisms by which we think that this could occur. First one is going back to the migrating motor complex.

I talked about this quite a lot in episode three (Listen to WHEN to eat with IBS) when I talked about when to eat.  I was talking about how to engage this little cleaning mechanism that goes through your small intestine. It moves through the small intestine when we haven’t eaten, keeps it clean, gets rid of old food, dead bacteria and just like debris that we need to get rid of.

The thing to remember is you can have a slow migrating motor complex, so a slow cleaning process, but have diarrhoea, or a fast transit of food through your colon. So just because you’ve got diarrhoea doesn’t mean you haven’t got slow migrating motor complex, and this is something that is really important.

Now, because a lot of people who have post infectious IBS to have diarrhoea predominant symptoms.

Slowing down the MMC

So the way that this works, is a little bit complicated. But basically you eat a food that is infected with a bacteria. This pathogen will release a toxin and the toxin damages your gut cells.

The type of toxin that is released is called cytolethal distending toxin. So it’s released into the gut by the pathogen. And because it’s damaging your cells, your immune system sweeps into action.

Now that cytolethal distending toxin, let’s just call it CDT.  Your immune system will release an antibody like an anti-C D T to minimize this damage. Your body’s trying to protect you from the damage to the pathogen. Now the problem is with this anti C D T antibody is that it can cross react with a protein that helps us with our migrating motor complex.

There is a protein called vinculin that is released to help connect our nerve cells in the gut. These cells, called the cells of Cajal, move the migrating motor complex along. If they do not have the vinculin protein, then they can become a bit damaged and that process can slow down.

The problem is that this anti CDT, the anti-toxin antibody, can cross react with vinculin and create Anti-vinculin antibodies. So your body is stopping the process. It’s almost like an autoimmune condition where your body is doing something to attack itself. Something that we don’t really want it to do.

We need our migrating motor complex to clean!

If your migrating motor complex doesn’t work properly, if it is slowed down and stopped, you can end up with more bacteria in your small intestine. That interferes with your digestive processes. It can cause all the symptoms like IBS, like bloating, gas, pain, diarrhea.

And other systemic problems like brain fog, aching joints, and bladder pain can be very much associated with, this overgrowth of bacteria because they’re interfering with your body’s natural digestive processes.

2. A stomach bug could cause low level chronic inflammation

The other way that an infection could change your digestion long term is that it can alter your immune function in the gut. So, as I mentioned, your body is kickstarting this inflammatory cascade to try and remove the pathogen. So it’s drawing water in to cause you diarrhea to wash it away.

It’s causing you to vomit, and this is really turning your immune system on. You can often feel achy, shivery, a bit fluey when you have a real acute infection. It could be that your immune system doesn’t quite switch off. So you’ve got low grade chronic inflammation in the digestive tract. That is causing you to maldigest your food on a longer term basis.

We don’t really know a lot about this. But there are sort of signs that some people with IBS have got increased inflammation markers, at a low, low level. So not at the level that would be considered to be inflammatory bowel disease.

3. Food poisoning could change the gut microbiome

The third reason why an infection could cause longer lasting IBS symptoms would be a longer lasting change in your gut microbes.

So potentially this infection has altered the bacteria in your small and large intestine to the extent that your body really struggles to recover it.

And it could be reliant on diet, you know, how much fiber you’re eating. How many plants you’re eating. This can impact on your ability to regain a healthy gut microbiome after an infection.

And the very last thing I’ll mention, just before we get into what to actually do about it. Is just to say some people never really recovered after Covid. And felt like their gut was never the same. They kind of ended up with a type of IBS after getting Covid a few years ago. So just an additional relevant recent development in terms of post infectious IBS.

Treatment for post infectious IBS

The treatment for IBS after an infection is pretty similar to any other type of IBS. It depends a little bit on the types of symptoms that you’re getting, the types of reactions that you’re getting to food and things that you do, to see what is going to work for you.

But I think I would break it down into:

  1. food and dietary triggers
  2. managing your nervous system and the migrating motor complex
  3. trying to rebuild your gut microbiome
  4. your general health and well being.

So let’s get into each of those

Post infectious IBS diet

Dietary wise, we’re really talking about symptom management. So how to reduce the effect of food on your digestion. Rather than looking to, you know, cure IBS or remove this post infectious IBS from your life. It’s more about how to manage your symptoms.

Key diets that you can try would be to trial the low FODMAP diet, and this is a way of identifying which particular types of starches or carbohydrates may be an issue for you.

Is it more to do with fructose? Is it lactose? Is it the fructans, which includes wheat, onion and garlic? Going through this very rigorous process with the low FODMAP diet can help you identify which particular foods are more of an issue for you. But it’s not going to necessarily resolve your symptoms.

It’s going to help you better manage it. So that is one approach.

There are other elimination diets and sometimes people find reducing their fiber intake can be helpful. For other people. It’s increasing your fiber intake. So there’s definitely not one rule that works for everybody who has IBS, or specifically for this type of IBS.

Developing the gut microbiome for post infectious IBS

Now, the reason reducing your fibre long term doesn’t work is that you are then going to be reducing the amount of good gut bacteria in your gut microbiome.

This is one of the things that we need to maintain if we want good gut health longer term. And one of those four areas that I think we can work on is getting good colonic, large intestine. Gut microbes that are basically reliant on you eating a good high fibre diet.

If you don’t have fibre in your diet you won’t have a good range of gut microbes. Because they feed off fibre from your food. So that’s one of the things you can do to try and start changing your gut microbes.

Could probiotics work?

The other thing is to try taking probiotics to put some live bacteria in you. This can be a bit problematic because for some people it can cause more bloating.

So you have to choose the type of probiotic very carefully and you have to think about, how to take them in order to try to minimize your symptoms.

Improving your migrating motor complex

Now, the other two things that I think are really important is trying to get better control over this. migrating motor complex.

So I mentioned about the beginning, the nervous system impulse that sort of moves through your gut and helps it clean. We want to try and reconnect this process.

Now, in post infectious IBS, this can be a little bit tricky because you might have damaged some of the cells. If you remember and go back to episode three, if you need a little bit more help with this. Things that you can do to help support your migrating motor complex is to eat at regular times every day, eat your breakfast, your lunch and your dinner at the same time, if possible, every day.

Creating a meal routine

Now, I’m not talking about a regular strict routine, but just a normal habit, like a general guideline that around 7 30, you have your breakfast around 12 o’clock, you have lunch, whatever it is, it doesn’t matter. What matters is that you keep to a regular routine. It’s not a rule. It’s like a guideline. an overnight fast can also be very, very helpful. And this is encouraging the migrating motor complex to work.

So if your problem is in the small intestine, we want to get this migrating motor complex working again, we need to give it time to do its thing.

It only helps it do its work when you haven’t eaten for about an hour and a half. And it takes about an hour and a half for it to do its process. So we need to give it an overnight fast, ideally of 12 hours, or if you can manage 13 or 14 hours.

So finishing your dinner at six and not eating again until eight the next day. That’s 14 hours.

Most of that time you’re asleep, but you need to not eat in between in order to let it do its work. That is going to help to keep your small intestine clean from old debris and help it to clean itself.

Prokinetics for the migrating motor complex

The other thing is you might consider a prokinetic. These can be either medication or herbs that help to kickstart this process.

One of the ones I use the majority of time with my clients is ginger. You can get some prokinetic, combination products. But often they will include a whole range of different herbs and things that could potentially cause problems for people. So I try to use single product at the beginning until we know that they’re going to be okay. Which is why ginger is helpful.

Take it overnight. You can take supplements during this overnight fast, and it encourages your migrating motor complex to work better. Other things that can help is taking 5-HTP, but you shouldn’t take it when you take antidepressants. You shouldn’t take it in a whole range of other conditions, so I wouldn’t suggest it’s suitable for everyone and I don’t use it that often.

So those two things you can do, so it’s creating an overnight fast, eat at regular times and potentially consider a prokinetic to try and kickstart your migrating motor complex. Those are helpful.

Rebuilding your wellbeing 

The fourth area that I want to really stress as well is just general lifestyle support. It’s all the basics about general well being that can be really helpful. Making sure you are finding time to relax. 

That could be doing things that you find fun. It could just be switching off and watching Netflix for an hour. But making sure you have some time where you sit down and you switch off.

Now for some people, you do find it relaxing scrolling through your phone. For other people, it’s not real relaxation. You’re not actually switching off. And you kind of come out of those scrolling half hours feeling quite wired and stressed. It’s not actually relaxing. But often that is one of the first things we do as we reach for our phone.

So, managing your stress levels in a healthy way can be very helpful.

Building in rest to recover

Also, making sure you have enough sleep.

Allowing yourself eight hours to get a proper sleep. Some people going to bed and they’re only giving themselves six hours before they need to get up again. There’s going to be no way you’re going to get eight hours sleep. Now, not everyone needs eight hours sleep to be fair. But roughly, that is a good amount of time to try and aim for at least getting rest in your day.

Also, gentle exercise, daily movement, really important. And I cannot stress this enough in terms of making sure that you feel well again. It’s not just about taking a pill or changing your diet. You’ve got to engage in these things around getting better sleep, helping you feel some joy again.

Trying to make time in your life for things that you enjoy. And that can be really hard when you’ve been living with a chronic health condition for so long.

Being in nature helps you relax

One of the best ways to do that is spending some time outside, spending some time in nature. And it can be really relaxing. There’s been research showing that just like looking at trees and looking at the sea is actually very calming for us as humans.

And so we spend a lot of time inside and trying to get outside. Trying to get a bit of daylight as well, which also helps regulate your sleep.

Has it led to SIBO?

If your post infectious IBS has led you to get SIBO, and I’m going to do another whole episode on that next week. Really diving much more into this small intestine bacterial overgrowth.

There are varying types of medication that you can take in order to kill off some of the microbes that could be living in your small intestine. Try and get rid of them and reduce down the amount of fermentation, gas, bloating. And that kind of thing that could be interfering with your digestive processes and making you feel really poorly.

In summary

To summarize a couple of things that you can focus on if you think you’ve got post infectious IBS.

Firstly would be to identify your food triggers. I suggest doing that via either the low FODMAP diet or another clear elimination diet. With very clear rules and you understand what you’re getting out of it. That will help you identify whether certain foods are making things worse.

Sometimes just taking them all out of your diet, letting your body recover for a little bit, letting your immune system calm down can be enough. To bring them back in again and eat a normal diet. Generally, though, once you’ve identified your food triggers outside of those triggers, you want to be eating as wide a variety as possible.

Eating a really good range of different plants and proteins and making sure that you are getting a broad and balanced diet. And part of that is about feeding the good gut bacteria and making sure you’ve got really good colonies of beneficial gut microbes in your large intestine. So firstly, find out if there’s food triggers.

Apart from the food triggers, eat almost everything else that you can and try and eat lots of fiber, lots of protein.

And that will help you potentially to increase your gut microbes. You might want to expediate that, speed it up a bit, by taking a probiotic supplement.

That can be really helpful for some people who have IBS, and people can find quite good improvements, but it depends a lot on the type of probiotic that you take.

Then thirdly, you want to make sure that your lifestyle factors are all in check, so you’re getting enough sleep, you’re managing your stress, you’re trying to find time to exercise. Try and find a little bit of calm in your day by practicing deep breathing, that sort of thing. Because they sound really basic, but they are really helpful factors in overcoming IBS.

Work with an IBS nutrition expert

And then I’m definitely going to recommend working with somebody who definitely understands IBS and understands SIBO. And if you think I can help you, all you need to do is get in touch with me, via my email address.

Let me know that you’d like to set up a discovery call. I just have a quick call with people I work with in order to check that we are a good fit to work together, check that you like me and I think I can help you and that we can work together well and then we can set up a time to get started on your three month gut reset.

And that is my program where I take you through diet and lifestyle factors in order to help you get your life back. Feeling that you’ve got control of your digestive system rather than letting IBS run your life.

Right, that’s it for this week. I will see you next week.

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