The Food Medic - S5 E9: IBS, Probiotics and Prebiotics

Episode Date: March 1, 2021

In this week's episode Hazel is joined by Dr Eirini Dimidi, a registered dietitian and Lecturer in Nutritional Sciences at KCL. Dr Dimidi is undertaking research on nutrition-based interventions, including fibre, plant foods, prebiotics, probiotics, and the low FODMAP diet, in gastrointestinal health. Topics include:* What is gut health?* How do we know if we have a healthy gut microbiota?* IBS: diagnosis, management, and dietary advice* The Low FODMAP diet * Probiotics and their role in IBS and in healthy individuals* Evidence for probiotic food and drink in gut healthn* IBS and a plant-based diet* Food and Mood: the gut-brain axis.If you loved this episode make sure to give it a review, rating (hopefully 5 stars) and share it with your friends and family. @thefoodmedic/www.thefoodmedic.co.uk Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

What's better than a well-marbled ribeye sizzling on the barbecue? A well-marbled ribeye sizzling on the barbecue that was carefully selected by an Instacart shopper and delivered to your door. A well-marbled ribeye you ordered without even leaving the kiddie pool. Whatever groceries your summer calls for, Instacart has you covered. Download the Instacart app and enjoy $0 delivery fees on your first three orders. Service fees, exclusions, and terms apply. Instacart. Grocer $0 delivery fees on your first three orders. Service fees, exclusions and terms apply. Instacart, groceries that over-deliver. Hey everyone and welcome back to the Food Medic Podcast. I'm your host as always, Dr. Hazel Wallace. On this episode, I'm joined by Dr. Irini Damidi, a registered dietitian and lecturer in nutritional sciences at King's College

London. In 2016, she was awarded a PhD from King's College London, where she investigated the symptomatic, physiological and microbiological impact of probiotics in constipation. Dr. Damidi is undertaking research on nutrition-based interventions, including fiber, plant-based foods, prebiotics, probiotics and the low FODMAP diet in gastrointestinal health. While we talk about gut health a lot on this podcast I wanted to dive a little deeper into the research and science on IBS, probiotics and prebiotics and I know this is a topic that many of you are interested in so I hope you enjoy it just as much as I enjoyed recording it. This podcast episode is sponsored by Carex. More than ever we need to be more conscious of our

hand hygiene practices both inside the home and out. The new antibacterial hand and surface sanitizer spray from Carex protects against 99.99% of bacteria and viruses on the go. This sanitizer has dual purpose, safe for both hands and for use on surfaces, which allows you to feel safe when commuting to work, out doing the groceries or picking up your coffee to go. Pop it in your bag or keep it in the car. The quick drying antibacterial spray formulation gives you peace of mind when you're out and about and don't have access to hand washing facilities. So first of all it's so wonderful to have you on the Food Medic podcast. I'm very pleased to be here today with you and talk about all things about gut health and IBS.

Absolutely so you joined us for the Future Food Conference, which was virtual this year, or last year, actually. And I loved your talk so much so that I was, you know, thinking to myself, I need to get this on a podcast. Well, thank you for that. I yeah, I'm very happy to be here. And hopefully people will find the information we'll talk about and share useful. Absolutely. So for people who are not familiar with your work, it would be great to just start out with a bit about your professional and academic background and what research you're currently doing. Sure. So I am a lecturer in nutrition and my work focuses a lot on advancing our understanding on how diet can be used to optimize our gut health but also help manage certain gut conditions. Now in terms of my

background, I am a nutritionist and a registered dietitian and a few years ago I completed my PhD which examined the effect of probiotics on symptoms, but also the gut microbiota of people that suffer with constipation. And nowadays, as part of my academic position, I'm doing a lot of clinical research on constipation and irritable bowel syndrome, and how several dietary interventions such as fiber or plant-based foods and probiotics can affect gut symptoms and how we can use diet in general to improve symptoms. Amazing. So let's just kind of bring it back to basics and start with the gut because we mentioned gut health and I think everyone's familiar with that term but what do

we actually mean when we talk about the gut because we're not just talking about our stomach or our intestines but there's lots of other things that are going on in there. Absolutely and first it's important to say that we don't have one specific definition for what exactly gut health is and some may say that it is the absence of any gut symptoms or the absence of any gut conditions. But as you mentioned, it is so much more than that. Gut health includes the effective digestion and absorption of nutrients, the normal function of our immune system and our endocrine system,

so our system that is primarily responsible for our hormones, the gut microbiota and its function and gut motility. So for example, all the contractions that our gut does to mix our food and therefore be digested and absorbed appropriately or to push the contents down the gut. And we know that most of these aspects that determine gut health are interrelated too. So for example, the gut microbiota can affect the immune system and vice versa. So there's many, many different factors that contribute to what we call gut health. Amazing. And the term microbiome or microbiota is very on topic at the moment. What do we mean about it? And how do we know if we've got a healthy gut environment?

They are very on topic indeed. Now, the microbiome and the microbiota are two slightly different terms. The microbiome refers to all the different genetic material, all the genes that microorganisms contain that live in our body or on our body. And we actually have 200 times more microbiome genes in our body than human genes. So we understand here we're talking about a huge, huge amount. The microbiota refers to the community of those microorganisms. So instead of looking at the genes, we're looking at the type of bacteria or the number of bacteria, fungi and viruses, for example, that live in or on our body. And for example, we have skin microbiota or mouth microbiota. And of course, we have the gut microbiota.

Now, we hear a lot about having that perfect healthy gut microbiota. But the reality is that there is not one single way a healthy gut microbiota looks like. Actually, we have a research study that was conducted in a little bit over 200 healthy people. And they tried to analyze their microbiota and figure out what that healthy microbiota looked like. And what they showed was a huge variability in the gut microbiota. There was not a single profile that everybody shared. But what we do know is that there are certain characteristics of the gut microbiota that may make it healthier. So for example, having more bacteria that we know provide us health benefits, and of course, less of those that don't do that or do the opposite.

And in terms of how we know if we have a healthy microbiota this is tricky you will see many many commercial companies claiming they provide tests that promise to give that answer for you however these are not validated tests and we do not recommend them so what you can do instead to aim for an as healthy gut microbiota as possible is by ensuring you follow a healthy diet rich in different types of fiber and plant-based foods and in general following as healthy lifestyle as possible so for example in terms of physical activity good sleep etc. Absolutely and we know even the last two things that you mentioned getting good sleep we know that there's a really strong link between our brain and our gut and what goes on inside our head

and how stressed we are that can have a huge impact on the function of our gut. Absolutely. And not just that, but we know that communication that happens between the gut and the brain is also mediated by the gut microbiota itself. So the gut microbiota can affect that communication quite a lot. Yeah. And one condition that's very tightly linked between the gut and the brain is Irritable Bowel Syndrome or IBS. And this has been a big focus of your research. And so first of all, let's talk about how it starts and what we know when it comes to what causes it.

Well unfortunately we don't know exactly what causes IBS. It's quite tricky understanding this at the moment. However we do have some indications of specific risk factors that may contribute to the development of IBS. We know, for example, that having a gut infection, for example, food poisoning, increases the risk of developing IBS because of the tremendous impact it can have on the gut. And other factors that may contribute are an altered function of the immune, the endocrine, or the the nervous system an altered gut microbiota our genetics as well and also psychological factors seem to play a very important role too such as stress and depression and comes back to that communication that we were talking about between the gut and the brain again

yeah and so because we don't know what causes it and the symptoms can overlap with lots of other conditions to do with our gut, how are we diagnosing it and how are we treating it? Now, IBS is diagnosed using symptom-based criteria and only after other possible cat diseases have been excluded as a diagnosis. So for example, all patients with suspected IBS in the UK must have a test to exclude the possibility of having celiac disease, exactly because as you said, symptoms can overlap. Now, once this investigation has been done and other suspected cat diseases have been excluded, We'll look at the symptoms that the patient suffers to determine if they have IBS or not.

And strictly speaking, the criteria for having IBS, for somebody to be diagnosed with IBS, they would need to have abdominal pain for at least one day per week in the last three months. And this pain relates to their bowel movements or the bowel movement frequency or consistency. So for example, they would have more frequent or looser stools when they experience that abdominal pain or the opposite, less frequent or harder stools. Now, in terms of how it is treated, firstline treatment always involves dietary and lifestyle changes.

And if these fail, then there's also several medications that can be used to manage symptoms such as antispasmodics. And of course, psychological interventions have also been shown to be effective, such as cognitive behavioral therapy. And so if we just talk a little bit about the first line dietary advice when it comes to IBS because I think a lot of people are aware of the FODMAP diet or have heard of it but before we get to that there are some things that we can change in our diet before thinking about possibly going down the route of a FODMAP diet. Absolutely, you're right. The low FODMAP diet shouldn't be the first thing that you try. There's definitely other dietary changes that you

could do to see if these would help improve your symptoms. So the first line advice involves reducing the intake of certain dietary substances that we know may irritate the gut and worsen the symptoms. So for example, alcohol, caffeine, foods that are very high in fat, and spicy foods. And for some people, adjusting the type of fiber they consume may also help. And also probiotics could also be trialed as part of the first line advice. So these are usually the strategies that are being recommended as part of the first line dietary advice in IBS. And is there anywhere that you can signpost people for advice on these kind of things? Because it's going to be dependent on the type of IBS they have as well.

So there's several sources online that you could look at for credible information in IBS. For example, the British Dietetic Association has a food fact leaflet available online on IBS and the different dietary management options that are available. I would say that if you do struggle with making any changes in your diet, I would suggest that you visit your GP and perhaps ask for a call to your dietician. But as a first go to a reading, I would at the moment target the BDA website. Okay, sounds good. And so if someone's tried all these things that they've looked at their diet, they've looked at their lifestyle, and they're really struggling, medication isn't helping. And they've heard about the FODMAP diet. First of all, let's

chat a little bit about this diet and how it works. So what's the mechanism? How does it improve the symptoms of IBS? So the low FODMAP diet is basically a diet that is low in what we call fermentable carbohydrates. So carbohydrates that are fermented by our gut microbiota, and it's also low in polyols. So what the low FODMAP diet does is that it restricts the intake of foods that are high in FODMAP. And as a result, what it aims to do is to reduce the gas production that takes place from our gut microbiota when those FODMAPs reach our colon, so the large part of the gut.

But the point is to also limit the water content that is found within our gut. And that is because we know that extra gas production and water in the gut can lead to symptoms of abdominal pain, bloating, wind, and also diarrhea and loose stools. So by restricting those high FODMAP foods, we're trying to limit these effects and hopefully see an improvement in symptoms. And indeed, clinical trials do show that the low FODMAP diet improves IBS symptoms in approximately 70% of patients. So it can work in some. However, what I do want to say is that there's a few things that we always need to emphasize when we talk about this diet. The very, very important point is that this diet consists of three stages, which the first stage is a restriction stage, where we do restrict those high FODMAP foods, or we reduce their intake before we gradually

reintroduce them. Now, this restriction stage is very important that it only lasts for a maximum of eight weeks. We know that the diet leads to some unfavorable changes in the gut microbiota. It may also lead to lower intakes of key nutrients that we need. So it's very important that we are not restricting high FODMAP foods in the long term. And because of the complexity of the diet, as well as the risks that I just mentioned, it's important that people don't try to do it on their own. And it is better that it's followed under the supervision and guidance of a dietitian. And that's actually the guidance that is included in the formal guidelines that are being followed in

the UK. And last but not least, we do say that it can be effective, low FODMAP diet and it does work for some people but it will not work for everyone so some people will need to either try again the first line advice if they haven't for some reason all right already or move on to medication or psychological interventions that are available to them so it doesn't work for everyone. Yeah, I think that's an important point. And moving on from IBS, we mentioned or you mentioned in the beginning probiotics. And again, this is a term that more so in recent years, people have been talking about a lot more, you know, from not just probiotic rich foods, but also probiotic supplements. And I think, first of all, it'd be really important to chat about what probiotics are versus prebiotics, which were also mentioned at the start. And what does the research say

in terms of the role in IBS? Are there specific probiotics you can take for IBS? So first, let's talk about the difference between probiotics and prebiotics. So probiotics are basically microorganisms that we consume. So for example, we actually consume bacterial fungi that can be found in yogurt, as an example, whereas prebiotics are the food that microorganisms in our gut consume so our gut microbiota consume and a very common type of prebiotic is fermentable fiber here so so that is the difference probiotics are microorganisms whereas prebiotics are the food that we feed the microorganisms when that food reaches the gut. When it comes to evidence in IBS, the research here is not very strong.

It's a little bit inconclusive at the moment. There are some probiotics that show some benefits, but other probiotics show no benefit at all. It seems to be really dependent on the type of probiotic, the type of IBS, so if it's constipation-predominant or diarrhea-predominant, and also the key symptoms that we're trying to address to different people. At the moment, we do not formally advise one specific probiotic because of the lack of high quality, stronger evidence.

Instead, what the formal guidelines recommend is that if a patient wants to try a prebiotic, they should try one product at a time for a minimum of four weeks and then monitor the effects and how they are getting on. Yeah. And so finding a suitable probiotic, because there's so many on the market, is there anywhere that you'd advise people to go to or is it just a discussion they should be having with their healthcare provider? Well, there's definitely available resources

from published reviews that summarize the evidence of different probiotic supplements on IBS that can be accessed by healthcare professionals. When it comes to patients, there is a probiotic guide that has been developed by the US that is accessed for free and people can access it, filter it through depending on different conditions, specifically now in IBS and see which different products have been tested and what the level of evidence is, which may help them make a decision. But ultimately, I would say it would be good

practice to have a discussion with a healthcare professional that is aware of all the different research and will be able to make recommendations based on their specific symptoms as well. And basically tell them if it is appropriate for their case as well. Okay, perfect. And so when it comes to probiotics, like we mentioned, they're available in loads of supermarkets, you can also get lots of probiotic enriched foods and things like that is there any benefit in someone who does not have any gut issues to start taking a probiotic supplement well it appears that the answer for this is no we know that from trials that probiotics do not impact the gut microbiota in healthy people And people who are already healthy, it seems it's very unlikely they will experience any meaningful benefits from taking probiotics. So to answer this with what we know

right now, it appears that there's no need to spend money to probiotic supplements if you are healthy. Consuming probiotic containing food, so for example, yogurt, or other foods that contain microorganisms, such as fermented foods, if this is something that people enjoy having as part of their diet, then definitely go for it. But it's unlikely supplements will have any additional benefits if you're already healthy. Absolutely. And so when it comes to probiotic rich foods, like you mentioned, like kefir, kombucha, live yogurts, do we have much evidence to say that they offer a benefit to our gut? We have been receiving this question in the last, I think, three years so often that my team and I decided to actually look at the evidence very thoroughly for that and identify any trials that have given us the answer.

And we found very little evidence available. For example, there's no good quality studies that have been done on kefir or kimchi or kombucha when it comes to IBS specifically or other disorders as well. There is one study when it comes to IBS that suggests sourdough bread may be better tolerated by people with IBS than normal bread because of the fermentation process reducing the FODMAP content. But this is just one trial that hasn't been replicated since. So actually, there's very, very little evidence available on fermented foods. But again, it's only been recently that there's been that surge in interest in fermented foods. So I do believe that there's going to be more available later on. Another thing that may be applicable for populations with IBS, because there is an

overlap with lactose intolerance, there is evidence from randomized control trials that kefir may be better tolerated than normal milk, again, because of the fermentation process reducing lactose content. So that's where we stand right now. There's not much more, but I am sure that in the future, we'll have more evidence to be able to give a better informed answer on that. Absolutely. I agree. And then thinking about prebiotics, I think, from a supplement point of view, they're probably less popular, but you can still find prebiotic supplements, but you can find them in loads of foods. So first of all, where can we find them? Which foods can we find them in? And is this something that IBS patients should be supplementing with? So prebiotics, as I mentioned earlier,

the most common type of prebiotic is fermentable fiber. They can be found in many foods such as certain fruits, certain vegetables, legumes, some nuts and seeds, and also starchy foods. So for example, bread and pasta. And as you mentioned, again, we can find it in supplements as well. Now, when it comes to IBS, we have evidence that prebiotics can indeed increase the concentration of some good bacteria in our gut, which is great. But what we have also seen is that they do not improve symptoms specifically. In some cases, they can worsen some. So for example, wind may be worse, which makes sense from a mechanistic point of view, because it may increase gas production. So taking a prebiotic supplement is not going to be

helpful symptom wise. However, we should still be aiming to consume a diet that is rich in prebiotic rich foods, because of the benefits for the gut microbiota and gut health overall but of course this should be done up to the tolerance levels that an individual may have but when it comes to supplements I definitely would invest in prebiotic supplements and just focus on having a healthy diet with high fiber foods. Absolutely. I think there's so many food options there that you can boost your prebiotic intake. And so prebiotics are found in plant-based foods. And a lot of people are choosing to go vegan right now. And naturally, that means more plants, more fiber. But for someone who has IBS, they may be more hypersensitive to high fiber foods.

So do you think it's possible for someone with IBS to follow a vegan diet without exacerbating their symptoms? Absolutely, it is possible. Now, as you said, following a vegan diet will mean that the diet is very high in foods, maybe very high in foods that can trigger symptoms. So specific types of fiber or food maps, which is why some people find that their symptoms exacerbate when they are on a vegan diet. However, it is definitely possible to be vegan and control your symptoms of IBS. It may require some changes in your diet, such as

swapping some foods, for example, going for a low FODMAP vegetable rather than a high FODMAP vegetable that may trigger your symptoms, at least for some period of time until symptoms improve. And then we can try to reintroduce them and increase the quantity consumed up to the tolerance level that someone may have. But yes, it is possible to be vegan and control your symptoms of IBS. I'm sure a lot of people will find that reassuring to hear. And then, so we mentioned the dietary interventions for IBS. And when it comes to medication medication there are a few options antispasmodics and peppermint oil and things like that but we also mentioned that there is

an option for psychological input and that's all based on the gut brain axis like we mentioned so when it comes to IBS what is the research saying in terms of the role of psychological interventions? So I find the gut-brain axis such an interesting area that we're learning more and more about. Again, that communication between the brain and the gut. And yes, it plays an important role in IBS. Actually, IBS is officially recognized as a disorder related to the gut-brain axis. So that's the formal term for that communication, which is not surprising given that we know that psychological factors such as stress, anxiety, and depression contribute to the

development of IBS symptoms. But we also know from research that certain interventions that target the brain, such as antidepressants, cognitive behavioral therapy, mindfulness, yoga exercise have been shown to improve symptoms. So yes, it does seem to play an important role and psychological interventions can be effective in IBS in some patients. Yeah, 100%. interventions can be effective in IBS in some patients. Yeah 100% and so I guess before you go it would be great to signpost people to if they want to find out more about you and the work that you're doing and read more about IBS and kind of the ongoing research that's happening sure so i um people could follow me on my social media i

on twitter it's at irini dimidi so my first name and last name and i do have an instagram but at the moment it's in my native language which is greek so if you have any great listeners here, the Instagram handle is at dr.irini.dmidi. And that's usually these are the two outlets where I communicate our research and our research findings and any other publications. Amazing. Well, thank you so much for joining us today. It was really interesting to hear the work that you're doing and also hear a bit more about IBS. Thank you for having me.

It's been a real pleasure. Okay, team, that was a whistle-stop tour through IBS and gut health. This was also episode nine of this season, which means we have our season finale next week. The topic will be on sleep, and I will be interviewing Dr. Sophie Bostock on all of the questions that you guys sent in on social media. That's all from me, speak to you again next time.