Dr Rupy: Most probiotics on the market don't actually do anything.
Dr Megan Rossi: True.
Dr Rupy: Spicy. I should take probiotics after taking antibiotics.
Dr Megan Rossi: False. It's during, to protect your gut.
Dr Rupy: Okay, I'm going to get into that. If I eat fermented foods like kimchi, sauerkraut, I don't need to take probiotic supplements.
Dr Megan Rossi: Conditions apply. They're different things.
Dr Rupy: Okay. Are fermented foods better than probiotic supplements?
Dr Megan Rossi: Again, different things, different indications.
Dr Rupy: Does freezing or cooking probiotic foods destroy some of those benefits?
Dr Megan Rossi: Freezing generally not, cooking generally yes.
Dr Rupy: Okay. And should we be avoiding additives and emulsifiers in our food as much as possible?
Dr Megan Rossi: We should become, I think, emulsifier aware. We don't need to go crazy on it.
Dr Rupy: I love that. Emulsifier aware. That could be on a t-shirt.
Dr Rupy: Let's unpack the world of probiotics, what they are, how they work, and who might actually benefit from taking them. Today you're going to learn about the science behind probiotic strains, and you'll learn a lot about what we mean by strains. We'll explore whether fermented foods like kefir and kimchi are enough, and discuss when probiotics may help people with issues like IBS or those who are looking to support their immune health or even prevent antibiotic-related side effects. And to help us with this super complicated topic, we've got Dr Megan Rossi on the show today. She's the founder of the Gut Health Doctor and is one of the most influential gut health specialists internationally and a leading research fellow at King's College London. She's a registered dietitian and nutritionist, but Dr Megan also has an award-winning PhD in probiotics. So she's the perfect person to be talking about probiotics with today. She's also the founder of the gut health food brand Bio&Me and she has launched a targeted range of clinically proven live bacteria supplements called Smart Strains. Dr Megan also shares how to navigate the supplement aisle with confidence, what to look for on the label such as genus, species and strain. Don't worry, you're going to know exactly what that means by the end of this podcast, and also how probiotics compare to foods with probiotic-like effects and other foundational gut health habits like fibre and plant diversity. If you've ever wondered whether probiotics are for you or which ones to trust, I think this is definitely the episode to tune into. I personally find this world utterly complicated, but hopefully, this is going to give you the confidence and the tools to navigate the marketing hype and choose the best products for your own needs. And just as a point I want to make here, there is no financial affiliation of any kind with Doctor's Kitchen and Dr Megan's brand of probiotics. If there ever is any financial affiliation with any one of my guests, their products, etc, we always make that super, super clear.
Dr Rupy: Megan, we're going to get into probiotics in a big way today. Let's start off by defining exactly what we mean by probiotics, because you've alluded to the differences between different products, and I don't think people understand the nuance of those distinctions.
Dr Megan Rossi: Yeah, no, it's it's such an important one, right? Because everyone's always like, "Oh, just have fermented foods or I'll just have a probiotic supplement." and like, they are very different things. So in terms of the definition of a probiotic, right? So it's these live microbes which when given in adequate amounts confer a health benefit. That's kind of the scientific definition. Now, the thing about fermented foods is if I was to make kefir at my house, you were to make it at your house, they would contain different strains of bacteria, so different types of bacteria. And therefore, it can't or it doesn't fit the definition of a probiotic because you need to know the exact strain. And I say strain, it's just like the type of bacteria. It's the scientific name for an individual type of bacteria. And so it would contain different ones and therefore we wouldn't know whether your strains had the benefit because we didn't know which ones are in it, right? So that's why I kind of make that really different, that distinguish between the two because they are different. There's different evidence in different areas.
Dr Rupy: Okay. So when people are buying a probiotic, let's assuming it's a good quality one, not like the majority of them on the market, but when they're buying one, they are getting a guaranteed strain of a microbe, whereas if you're growing it, in a kefir or a kimchi that you've made at home, you just don't know what you're getting, hence it's not considered to be a probiotic.
Dr Megan Rossi: Absolutely. 100% spot on. Yep.
Dr Rupy: Okay, great. So when we talk about probiotics specifically, if I'm in the the the health food store and I'm looking through this vast library of probiotics, what are the things that I'm looking for on the back of a packet in terms of the names? You've alluded to strains, but some of the things higher up the order.
Dr Megan Rossi: Yeah, look, I think it's a really important point that people need to start thinking about, "Well, why do you want to take a probiotic?" Right? I think before they go to the health food store and go to this section, because it can be so overwhelming. But there is no clinical evidence, there's never been a clinical trial that's shown that taking any type of probiotic, any type of strain, is going to improve your general gut health, like your microbial diversity. Right? So if you want general gut health improvements, that's where fermented foods comes in. There's this great study from Stanford University, they showed having a high fermented food diet actually increased the different types of microbes you've got in your gut, and actually also there was some reduction in markers of inflammation.
Dr Rupy: Okay.
Dr Megan Rossi: So I think that is one of the biggest myths that we should be busting that for general gut health, don't go down the probiotic supplement path, right? Have the fermented foods and all the plant diversity and those sorts of things.
Dr Rupy: So you answered one of my big questions already. So whether a daily probiotic supplement is actually something that could potentially have benefits for people that don't have a specific condition or a symptom or anything like that, it's not going to confer any benefits, or at least there's no evidence currently to suggest that there is any benefit.
Dr Megan Rossi: Exactly. So there's currently no evidence. And what I would say is there's a little bit of evidence, it was a one small clinical trial, but it showed that if you just went and took a random probiotic off the shelf after a course of antibiotics, your microbiome actually seemed to take longer to re-establish to your baseline compared to those who didn't take one. So actually, that's kind of, again, a small study, but for me, highlighting that these are live microorganisms. We shouldn't just be taking them as an insurance policy, the way they're being sold to us, right? Um, and I did my PhD in probiotics and you know, I've seen how powerful they can be in the clinical setting, and we, I'm sure we'll go into some of the clinical data where in certain indications, they can be really beneficial and powerful. But it's just this whole way that society has approached them. And it's not individuals' fault. I think it's the way the marketing claims have kind of led us to believe that if we want good gut health, we should take a probiotic when it's just not scientific at all.
Dr Rupy: Yeah, and I remember having those conversations with families and patients when I was working in the NHS that taking a probiotic after you've had your antibiotic course seems like a sensible thing to do. I mean, what's the harm in taking a probiotic? But to your point, when that study came out, I remember thinking, "Oh god, I've got to change my approach on this," because we are dealing with a, it's a supplement, but it's essentially having pharmaceutical-like effects, it's having medicinal effects. So we have to be careful about who's taking them, after which antibiotic, at what point during or after antibiotics? And you alluded to maybe during the antibiotic course might be the best course of action. But we have to be sensible about these and and and evidence-based.
Dr Megan Rossi: 100%. I think the other thing to think about is we should probably move away from this concept of take a probiotic or not take a probiotic, right? Because there's thousands of different strains. So, you were kind of alluding to before in terms of there's all the different types. We've people have heard of the Bifidobacterium genus. So that's just a family, right? But there's several hundreds of them. Go to the underneath layer, then you've got the species and that an example of that is lactis, right? So Bifidobacterium lactis. But again, there's many different types. So you need to go underneath of that and that's where you get the strain, like BB12. Right? So you need to really get to that strain level. And the way I describe it in clinic to people is if you have iron deficiency, I'm not going to go and give you a vitamin D supplement. I would give you the iron supplement, right? That's the exact same way we need to think about probiotics.
Dr Rupy: That's a really good way of thinking about it. I've got a deficiency in a mineral, ergo I'm going to take a micronutrient supplement, whereas what you're saying is, "No, you need to take the specific micronutrient supplement, not just a micronutrient supplement more broadly."
Dr Megan Rossi: Absolutely. Yeah, yeah. Or even if you go to the medication level, right? You know, you're not going to take blood pressure medication for your type 2 diabetes. Like you need to get specific if you want the therapeutic benefit that we've had these randomized control trials showing. Um, and with that, obviously, comes a whole lot of complexity, right? I appreciate not everyone's done a PhD in in probiotics or has studied this space. Um, and therefore it can be super confusing to be like, okay, which strain do I take? When do I take it? Why? What dose? What format? Because I think that's another thing that I see often is where, um, this like one format, i.e., liquid is way better than capsule or way better than powder has been pushed, right? But actually that, again, is not science-backed where it depends on what you're trying to manage and what the clinical trials have used. So there's, um, kind of these these gut models that a lot of the marketing teams have really pushed and be like, "Oh, look, it looks like this liquid has survived more than a capsule or a powder." And you're like, but I love gut models for hypothesis generating, right? Great. But we've got the human clinical trials where we see what happens in an actual human. Why don't we use that? So it's kind of a case, I think of, yeah, a lot of smokey mirrors around different things. And what I always says come back to, has there been a randomized control trial? What format did they use? And for things like upper respiratory tract infections, like colds and flu, actually, they've shown that in powder format, because you want it to activate in that upper respiratory region, right? Um, and if you're giving it as a capsule, then perhaps it's not going to be as effective. And one of the studies gave the exact same strain. It was preventing pneumonia, um, and those given it as a, you know, in the powder format, another one had as a nasogastric tube because these people were in hospital. So it bypassed the kind of upper respiratory region. And only that given as a powder format had a clinical result, a positive outcome in that study. So again, it's kind of this proof of mechanism. So it always for me comes down to we need to get specific. And I know it's so hard for people who aren't in this space to to get there. But we've had to do it with micronutrients, we've had to do it with medication. So it's just going to be this next generation of where we move to with probiotics.
Dr Rupy: Totally. So, um, if we just circle back to what we're looking for on a probiotic packet, right? So we're looking for the genus, the species, and the strain. If I'm looking at a probiotic and I can only sort of see the the genus, it's got lactobacilli in or um, maybe it says rhamnosus as the as the um species, is that like a bit of a red flag that it's just not good enough and they're not actually using the specific strain?
Dr Megan Rossi: Yeah, so it's a red flag. Um, that yeah, they haven't identified the strain. So I would never be taking something at a species level. And again, just to really hit home that point. It's, you know, an exaggerated one, but you know, E. coli species, right? Um, so a lot of people are like, "Oh, that's terrible." But actually at the strain level, you can have a lot of differences. So E. coli Nissle, I think it's like 1917 is the strain name. They're always really weird. So that one actually is one of the oldest probiotics on the market. It's got efficacy in ulcerative colitis. Okay. Whereas most of the other E. coli strains, you know, some of them can actually be deadly, right? And that's at the strain level. So if you're just focusing on the species level, they can have completely different effects. So I think it just feeds into, you know, this whole understanding of the gut microbiome, there's trillions of microbes in our gut. You know, each different one has a different skill set, does different things, and that's why people with more different types of microbes in them, you know, are healthier because they've got more skills and all of those sorts of assets. Um, so we just need to think of that and then think, "Okay, same goes with probiotics. Each individual strain will have a different functionality, different mechanism, will have a different role."
Dr Rupy: Got you. Um, I promise we're going to get to the specific use cases of when to use specific probiotics, but I want to get through the, you know, definitions of probiotics and exactly what we're talking about. So, um, let's talk a bit about form factor. So you've alluded to the fact that powdered is depending on the context, sometimes better than liquid or capsule. Um, is the only way to approach form factor, really thinking about, "Okay, what you're using it for?" So there's no such thing as a hierarchy of liquid is better than powdered, which is better than supplement or tablet form. Is that is that the right way of thinking?
Dr Megan Rossi: Yeah, so it's always because remember each strain will have different functionalities. So a lot of the strains like, um, Lactobacillus rhamnosus GG, so LGG, that's actually got the most scientific published papers on that strain in the entire world, right? So it's the most well-known, well-characterized one. That one actually is very much acid and bile acid resistant. Right? So actually that's quite good at being in a powder format. Whereas other ones actually maybe it does need to be protected from more of that acid, um, or needs to be given at a higher dose. So there's so much kind of complexity around that. So the way that I would always say to someone is just use the format that was used in the clinical trial showing the benefit that you're after because that's the best way to know. Um, you know, how it's going to work.
Dr Rupy: So for someone who's using it perhaps for IBS or IBD, um, you want something that's going to survive that acid bath when you go past the stomach and then the bile that that you're going to find in the small intestine and then making its way all the way to the large intestine, rather than something that you want to be working on a bit more locally or higher up the digestive tract.
Dr Megan Rossi: Exactly. But again, the only way you'll know that is just using the clinical data because again, a lot of the strains coming through, the probiotic strains actually are resistant, so you don't need to worry like, "Oh my gosh, you know, it's in the powder or it's in the liquid. It's not enterically coated capsule." Right? So it's always coming back down to the human clinical trials. And because we've got them, let's use them, right? So like, I think, you know, a lot of research areas where it's so so new, where we've only got animal studies or you know, gut models and that sometimes you have to go off mechanisms and then rely on that. But we don't. So I'm like, "Why go a step backwards?" Right? Let's just use the best results, the gold standard that we've got.
Dr Rupy: Totally. You mentioned a a complicated word there, enterically coated. What does that mean for me?
Dr Megan Rossi: So essentially that is just when it's um, kind of acid-resistant type of capsule. Um, and yeah, it's kind of, I think most of the strains to date with good evidence don't require that. Um, but some of the really sensitive ones might, yeah.
Dr Rupy: Okay, okay, great. Um, all right, so we've talked about form factor, we've talked about the making sure you're getting the right strain because it's the equivalent of taking a vitamin D tablet when you actually need an iron tablet. Uh, what about dose? So it seems in the world of probiotics, more is better. At least that's, you know, the way things are marketed. Is that strictly true?
Dr Megan Rossi: Not strictly true. I would say, I mean, there was one IBS study which a lot of people reference where the slightly lower dose had greater efficacy than a higher dose. Um, but that was kind of one of the only studies that showed that. So I think it's true to say that you need a certain dose to ensure it's in adequate amounts, right? Um, if it's a little bit higher, I wouldn't freak out, but ideally you're trying to match it to the dose. I wouldn't go under the dose shown in clinical trials to have a benefit. Um, and then on the on the point about the strains which we we didn't necessarily cover, but I think is an important one because I'm starting to see a lot with companies where, frustratingly, they just pull individual strains that on their own, the strain may have shown a benefit, but they just add it with other strains and then like, "Oh my god, we've got an amazing one with like 14 clinically-backed strains." And they've never tested it together. Right. And what we know about bacteria is they can compete, right? Yeah. So again, it comes down to this like, you need to have proven that that formulation is going to lead to the benefits that you want. You can't just think they're all going to be additive. Yeah. Because they are very competitive animals.
Dr Rupy: Well, it's using your analogy about pharmaceuticals, it's like me pairing an anti, an antihypertensive drug with a painkiller with a cholesterol-lowering drug with an antibiotic and saying, "Well, all of these individual drugs have done great stuff in their individual trials, so we're going to lump them all together and just give them to you in one handy pill."
Dr Megan Rossi: I love that analogy. It's it's exactly what's going on. And everyone's like, "Yeah, the more the better. The more the merrier." Like in that story, you're just like, "That is wild. That's a new concoction that will kill someone." Right?
Dr Rupy: Yeah, yeah, totally. Okay, great. So that's a really good point. So, like looking at multiple strains as a combo is not necessarily better in the same way a higher dose is not necessarily better as well.
Dr Megan Rossi: Okay, great. In terms of form factor, dose, um, survivability, all that kind of stuff. Are there any other things that people need to know about? Like is freeze drying better or is there certain preparation methods? Are those better in terms of
Dr Megan Rossi: No, again, it comes down to the individual strain will react in different way. So it's yeah, I think we've touched on the main ones in terms of getting that right strain, getting that right formulation, getting the right dose and the right format.
Dr Rupy: Okay. Let's talk about use cases. Um, so where do we have actual evidence that it could be beneficial and a useful adjunct to other therapies that somebody might be having?
Dr Megan Rossi: Yeah, so when I've kind of done a deep dive in this space, um, I believe there are four areas where I hand on heart say, you know, "I would recommend this to everyone." And actually a lot of people don't realize that the World Gastro Organization has guidelines on probiotics, which is very helpful, right? But again, clinicians that aren't specializing in this space just aren't aware of them. Um, so one of the areas where the World Gastro Organization has given level one evidence, the top level evidence, is for taking a specific strain of bacteria during antibiotics. So that is the LGG strain of bacteria during antibiotics at a dose of 10 billion CFUs, colony forming units, how we measure them, just think 10 billion bacteria, twice a day. And that's lactobacillus rhamnosus or GG. Yeah. LGG, yeah. Um, now they've been like this nomenclature update of Lactobacillus. They've kind of now split them to different names, but I think let's not go down that like as if it's not more complicated. So the current consensus is we'd let's just keep it with Lactobacillus for the the public thing, but just if any scientists are watching, they'll be aware of that. Um, so yes, and then in terms of I guess the clinical trials, so the randomized control trials, um, and placebo control, which I think if we've got the data again, it's like music to my ears because we know the placebo effect affects around 30% of people, right? And it's just if you believe you're doing something good, you start to slightly change how you're eating and all these other things which then overall has a different impact. So randomized, um, again, there's for the LGG that um in antibiotics has been shown in adults and in um children. So in children, all kids on antibiotics, half of them got the LGG strain, other half got placebo, obviously blinded, um, and those who had the LGG strain, um, had a it was about a 70% reduction in incidence of diarrhea during their antibiotics, um, compared to the the placebo group. And then in adults, again that same strain LGG reduced, um, their antibiotic-associated diarrhea again by around 70, maybe it's like 72% compared to placebo. Also reduced bloating and taste disturbances by I think it was like between 50 and 60% as well compared to placebo. So it's kind of it's got, you know, strong evidence. Placebo-controlled trials, which is why obviously Gastro, the World Gastro Organization gave a level one evidence.
Dr Rupy: That's great. So level one evidence, if anyone's looking this up on the websites, that's the highest level of evidence that we should be looking out for.
Dr Megan Rossi: Yeah. Yeah, yeah, yeah. So, I mean, we'll link to these World Gastro guidelines because I think it's quite important that they're disseminated and people are aware of them. Um, because they do a good job obviously in terms of looking at like the systematic reviews and the whole kind of body of evidence. Um, another one, um, that both the World Gastro and the leading pediatric guidelines, so ESPGHAN, um, recommend is for colicky babies. Um, so one of the strains is BB12 given at 1 billion CFU. Um, and again, I think the one of the clinical trials, there was two of them using that formulation. I think it was in close to 200 babies, the largest colicky probiotic study, and it significantly reduced fussing and crying in those who had the probiotic. I think it was like 150% times compared to placebo, increased sleeping duration by an extra 60 minutes per day compared to baseline, and then parents' quality of life also skyrocketed and again they were blinded though. So, it's like there is really convincing. And you know what it's, I mean, I don't know, did your little one have colic?
Dr Rupy: I mean, he didn't have colic, but you know, he he was definitely, obviously, he, you know, he regressed his sleeping and all the rest of it, but we were touch wood quite lucky with sleeping. But I've heard horror stories obviously being a clinician for many years and also my colleagues and everything. So anything that could have that drastic an improvement would be welcome. And I'm guessing that the side effect profile of probiotics is pretty low if if not nonexistent.
Dr Megan Rossi: Again, if it's the right strain. Right? So I, um, would be very cautious of the strain. So for example, the LGG strain actually has got really good efficacy, I think there's a meta-analysis in like like 10,000 babies, um, for preventing necrotizing enterocolitis in preterm infants. So it's like one of the safest. Yeah, yeah. So I wouldn't want to go and give a preterm infant BB12 unless there was, you know, convincing evidence of safety profile. Um, and just for the listener, that's a very severe um inflammatory condition of the bowel that is seen in in preterm infants. Yeah. Yeah, yeah. Um, so and then BB12 is the most um, published probiotic strain, probiotic Bifidobacterium strain. Okay. So again, really good safety data in in kids so from from birth, you know, it's like that safe data.
Dr Rupy: Got you. And just circling back to the antibiotics, sorry, I know we're jumping around a little bit here, but um, for the antibiotics, uh, the reduction in diarrhea symptoms, was it when folks were on a specific type of antibiotic or is it just different antibiotic courses for different reasons?
Dr Megan Rossi: Yeah, so the adult one, so in terms of the World Gastro Organization, their guidelines is just all antibiotics. They don't yeah. They don't um kind of specify according to the type of antibiotic. I don't I'm not aware of any specific studies that have gone into "Is it more efficacious if you have this type of antibiotic versus this type of antibiotic?" Um, in the
Dr Rupy: or like whether someone's got a UTI or an upper respiratory tract infection.
Dr Megan Rossi: Yeah. Um, and with the one of the papers I quoted in terms of the adults, um, who were all on antibiotics, that was for um H. pylori eradication, so it was triple therapy with um proton pump inhibitor. Whereas I think the children study was in children with all different types of antibiotics. I think they were all given, you know, whatever was called for. Um, and just for the listener, so H. pylori is something that we want to try and eradicate in people with gastritis that is thought to be due to Helicobacter pylori, which is something that we can treat with triple therapy, which is a PPI, antibiotic, and metronidazole.
Dr Rupy: Yeah. Is that it?
Dr Megan Rossi: I think it's two types of antibiotic.
Dr Rupy: Oh, sorry, two types of antibiotics and a PPI.
Dr Megan Rossi: Yeah. Yeah, yeah, yeah.
Dr Rupy: Cool. Um, okay, great. So that those are two big areas with lots of evidence. There were two others you said?
Dr Megan Rossi: Yeah, yeah. So another one is the, um, is based on a Cochrane review. Um, so the thing about the World Gastro Organization guidelines, love them, but very focused on gut-related things, right? So this is why it is such a confusing space. There's not like one place to go for all of the evidence because it's all different guidelines. Anyway. Um, so for, uh, Cochrane review for those who don't know, it's like an independent body where they pull together all the individual studies and assess it. And they've said that yes, specific strains of bacteria can help prevent and delay, um, or reduce the duration of cold and flu. Um, so in two of the clinical trials, placebo control one in kids, one in adults, they use the strains LGG and BB12 together. Um, and in the kids, it was an infants, which is why both of my kids are on it from birth. Um, so it was in the first year of life, they reduced the recurrence of upper respiratory tract infections, uh, by 50% compared to placebo. And in adults, it was, it was a reduction in the duration of the cold and flu by two days compared to placebo.
Dr Rupy: So this is when you're taking, so I've just started a cold, let's say, and I'm I'm like, oh, you know, doing my broth and I'm doing all that kind of stuff. This is when that starts and I start taking the probiotic?
Dr Megan Rossi: So the studies were prophylactic. So actually no, before, as a preventative. So they didn't have anything, then they took it, they were given it, that or the placebo, and looked over time the incidence of, um, upper respiratory tract infections.
Dr Rupy: How long did they follow them up for?
Dr Megan Rossi: So one of the clinical trials in adults, I think it was three months. The other one, I like to say six months in in children. Don't quote me on those exact. We'll link to the to the um, yeah, to the papers. Um, and yeah, and then in terms of I think the severity of symptoms in the adult one was like reduced by over 30%. Got you. Um, so so that indication, and then the last one, um, is bacterial vaginosis and thrush. So obviously, as a medic, you know how effective antifungals and, um, antibiotics are for those two, right? But the issue is relapse rate is huge.
Dr Rupy: And I wasn't aware that 75% of women will experience at least one episode of thrush in their lifetime.
Dr Rupy: Which is huge. Yeah, I mean, it kind of makes sense now, just thinking about like how many people we've seen with thrush. Yeah. And a lot of it, it comes down to previous antibiotic use and so I could probably, but it's still very high. It's still very high. Yeah.
Dr Megan Rossi: And then, yeah, the relapse, you know, between 40 to 60%, right? So yes, the medications are effective. And then so when people come and see me in clinic, they'd be like, "What can I do about this?" I'm like, "Sorry, it's like just the medical stuff." Like yes, obviously unperfumed soap and non-synthetic knickers and stuff like that. But like there is no evidence for the anti-candida diet, right? They'd all come to me like, "Oh, I want this diet." and I'm like, you know, cutting out fruit, like,
Dr Rupy: What is the anti-candida diet?
Dr Megan Rossi: So it's essentially, yeah, a diet that's not backed by any science, but essentially like reducing down things like fruit, high fruit, also some, um, cheeses and some grains and stuff with the concept that these are feeding the yeast. And therefore making you more susceptible to vaginal infections. Um, and, you know, they've they've done some studies, um, small studies, very historic, but they've given people like high doses of like actual sugar. Um, and shown that actually it doesn't link to an increase unless you've got diabetes, which obviously then you've got blood sugars are unregulated, all that sort of stuff. So the whole concept of the diet is just doesn't make sense. And there is a little bit of data suggesting that, um, like for bacterial vaginosis type of vaginal infection, um, having a high polyphenol, high plant diet can reduce your your risk. Um, it was an observational study, but still the concept is, well, then this anti-candida diet is cutting out some of these beneficial. Anyway. So my point of the story is like, "Sorry, I like this is, I would not recommend this." Anyway, so when I saw, um, some of the clinical data again, they used the specific combination of strains called, this is going to test my brain, LA14 and LHNOO1 with some lactoferrin, which is.
Dr Rupy: I was just going to say, you've got two kids. One is four, one is two, and the fact that you're just with no notes in front of you, you're just reeling out these strain levels is pretty amazing for me. So
Dr Megan Rossi: But then remember this is like this is my job. I work at Kings, you know. But um, yeah, but that's what, that's why I mean like how are we meant to, you know, the average person, you know, to do it. Anyway, hopefully we'll get there. Um, so yeah, so that's the kind of the formulation. So it was given to women, um, who had bacterial vaginosis diagnosed. So short-term antibiotics was given and then as an adjunct, additional therapy, either placebo or that formulation. Um, and by six months, um, those in the active, um, probiotic group had about I think it was like a 50% reduction in risk of relapse compared to the placebo group. And that same formulation has been given in those with vaginal thrush. Again, short-term course of antifungals, but as an adjunct therapy, additional therapy, uh, either the placebo or that formulation. And I think those who had that formulation had about a three-fold reduced risk of relapse of vaginal thrush. Wow. Um, so again, it's like, I mean, in the context of there's nothing else that we can actually offer. Yeah. That's that's actually super impressive.
Dr Megan Rossi: Yeah. And that's why I think, you know, where I really like when I've looked at all the literature, kind of my in my brain, the kind of criteria is has there been, um, is there a clinical guideline or has there been a systematic review showing that a probiotic can help in that area? If there has been, I went on to the next kind of criteria of like, well, is there a better therapy on the market? Because what's the point of having a probiotic that's going to improve something by 5% when actually this other therapy diet is hugely effective. And you see that with weight loss. Um, and and then the next level is, "Okay, well, if there has been, um, you know, there is this need that, has there been two randomized control trials using the same formulation showing the same kind of benefit?" So in my head, that's kind of the criteria I use to determine, "Is there good evidence to recommend one?" Um, and that last one, you're looking for replicability, so, you know, that gives a little bit more confidence that, you know, it's it's actually doing it.
Dr Megan Rossi: Exactly. And you're choosing the right strains. Because I feel like, you know, if there's 20 studies, we know like, you know, that's why the whole P value, when we talk about statistical analysis, right? You need to make sure that the P value is adequate is there's always going to be at least one where it's going to show the opposite effect just by chance. Yeah. So, um, yeah, that's kind of the criteria in my head. But then obviously, it is a really exciting space where there's always new studies coming out. Um, but I'm kind of unless I'm seeing someone one-on-one in clinic where they're like really want to try a probiotic, um, then that's my criteria. If they really want to try one and there has been a single randomized control trial, maybe no meta-analysis, then I might be like, "Okay, let's try and replicate that if you want to on a one-to-one basis." Um, but the chances of it actually working is I'm not overly convinced by, but if, you know, you're aware of that, let's go down that track.
Dr Rupy: Got you. And and so outside of those four indications, right, that you've looked at and the World Gastro Society, sorry, organization, um, have determined that there is evidence. Are you hopeful that there are other areas, but we just don't have the right studies or the right level of evidence for?
Dr Megan Rossi: Yeah, absolutely. So again, I'll link it. I've done quite a few healthcare professional webinars, but it's not overly high level. So if, you know, consumers uh want to watch it where I've broken down like tons of different um indications where I think, so I've got like good quality, so those four, then I've got the kind of emerging where I'm like, "Oh, this could be something." Um, but it didn't fit that criteria of like the two randomized control trials or there's no clinical guideline or systematic review. Um, and within that in that space there's things like psoriasis, um, non-alcoholic fatty liver disease, osteoarthritis, mental health where there's a bit of a murmur that it could be something coming. Um, but it's at a case where again, it's more of a one on one in clinic would I consider that versus publicly being like "worth taking a probiotic here," because I just think these are live microbes. They could be doing things that you don't want them to do. So I want to make sure I feel quite confident before I start being like, "Oh, just take it, you know." The whole kind of concept of insurance policy, I think can be dangerous here.
Dr Rupy: Yeah, yeah. I did um a little bit of uh uh searching around on PubMed. I just looked at the number of times probiotics in the title were looked at in papers between '95 and 2010. It was about 7,000. And between 2011 and 2025, it's like 50,000. So it's really exploded. And prior to that, there was like no mention of it pretty much. So it's really exploded recently. And I think the the sort of frustration of the general public is it seems like probiotics are already here and people are taking them and they're having these like wonderful stories online, etc. But when you speak to professionals, we're very cautious about it. And so there's this disconnect between marketing hype and evidence base. And this is where I think it's really important to have these discussions about specific areas that we know we can hang our hat on with some degree of confidence that probiotics may have an impact, and others like weight loss and dementia and mental health where there's promise, but you know what, probably would save your money for now.
Dr Megan Rossi: Oh, I would say just to clarify that weight loss and dementia, I would say currently not convincing evidence. Mental health is in the emerging. Just just to put that clarification in there because I don't want anyone to be like, "Oh, great, exciting."
Dr Rupy: Yeah, I know. When you said weight loss, my ears picked up. I'm like, "Okay, yeah, weight loss is probably going to be something."
Dr Megan Rossi: There's going to be huge. Is that being marketed at the moment? Have you seen that?
Dr Rupy: So I mean, you know, it it has been, right? Um, the systematic reviews are currently saying, "don't waste your money in that space." There's been a couple of little ones showing like small weight loss, but again, I think they're quite biased. And if you want to lose weight, you know, losing half a kilo off three months, it's pretty clinically non-significant. Right. Um, so I think for yeah, for now, unless there's some amazing strain. I mean, maybe it'll be fecal transplants where it's actually the whole microbiome seating versus specific strains. I think there's a lot more going on mechanistically with weight management, with appetite regulation and, um, all the different appetite hormones and stuff like that, you know, many of which are activated in the gut. So I think there's going to be a lot more that probably a probiotic wouldn't be able to help with weight management. Um,
Dr Rupy: Yeah. There's there's a lot of people doing fecal micro transplants themselves. We we won't go into that. Yeah, there's like, you know, YouTube videos and stuff about like, yeah, stool banking and all that kind of stuff.
Dr Megan Rossi: You know, there was a really cool just while we're talking about that because you know, I was in my early 20s, you know, doing it in the lab and it was just great times. Um, but actually, so obviously C. difficile, a really serious gut infection. We know that, you know, it's been approved and it's life-saving in those groups who don't respond to antibiotics. But actually more recently, there was a really convincing systematic review that came out for ulcerative colitis. And actually now, it's still obviously not mainstream medical therapy, but I think St Thomas's in London are now starting to consider it. The gastros for certain types of UC. Um, so anyone who's listening to this, you know, that might be something worth chatting to your gastro about.
Dr Rupy: That's super interesting. Yeah. As we're talking about mechanism, um, let's talk a little bit about the journey of a probiotic that you've chosen specifically for one of those four areas of of complaint. What is actually going on? So I'm taking this probiotic, whether it's a liquid or a capsule or whatever it might be, and it's going into my body and it's hopefully getting to the area where it needs to be in my digestive tract. Then what happens? What what's it doing?
Dr Megan Rossi: Yeah, so I mean, again, it will depend on the strain and how it acts. Like if you think of the the vaginal um evidence, right? So those, um, that formulation is taken orally, but it's been shown to arrive and survive in the vagina. And women are like, "Oh, how is that happening? Through the blood?" It is obviously not not through the blood for anyone, you know, not medical, that would just cause inflammation. It can't happen. Um, but it's through the wiping mechanism we we think is is the key, um, element. And that's why I think the lactoferrin helps with that kind of survival. So what happens is those microbes are thought to change the pH of the vagina and then prevent those things like candida, um, overgrowing because they only like to grow in certain types of environments, and also they eat all the food and prevent the other microbes from overgrowing. So that's the mechanism kind of in the vagina. Um, then when it's things like antibiotic-associated diarrhea, so during antibiotics, the LGG, like it is the most kind of characterized, I think there's many different mechanisms. It, um, I think it activates the immune system, obviously 70% of the immune system lives in the gut. So I think it kind of protects it a bit more or something like that. I think it also binds to sites that the bad microbes would have bound to and therefore kind of prevents it from doing that.
Dr Rupy: Okay, so just crowding them out or something?
Dr Megan Rossi: Yeah, kind of crowd them out. And then also certain types of microbes can produce, um, certain types of kind of toxins that will kill other microbes. Okay. So there's yeah, a whole lot of different mechanisms that we think is going on to explain the clinical results that we see.
Dr Rupy: Got you. Um, and a lot of people hear about these short-chain fatty acids that are being produced as byproducts of microbes in general, not just the probiotic strains that you'll be consuming, but also your natural ones. Is that something that's heightened by certain strains or is this
Dr Megan Rossi: It is a good question. I guess because you need obviously the the fibre, that's where the short-chain fatty acids are produced from that ferment. And I think most people probably have, you know, if you're having a decently high-fibre diet, you've probably got a decent amount of the short-chain fatty acid producing microbes in your gut. So I don't think the mechanism will really be around enhanced short-chain fatty acid production. Um, in fact, I'm not aware of any of the probiotic studies where they've showed increased levels of short-chain fatty acid. Whereas obviously like fibre studies and prebiotic studies, you do see an increase in a short-chain fatty acid production. So I think probably the, you know, obviously, yeah, again, there's some mechanistic studies that some people might not produce all the short-chain in the right amount. But again, yeah, I'm not aware of any. But again, you know, all the technicals, it it's quite difficult with short-chain fats. We at King's, um, College London, we measure short-chain fatty acids for a number of our clinical trials. And actually a lot of the short-chain acids get absorbed through the gut lining. And therefore, the amount that comes out in the store, if you're measuring in the store, it's not always a good indicator of how much is actually being produced. Okay. Um, so some of our studies actually we haven't really seen a difference even though like for a low fodmap diet where you would expect short-chain fa to reduce because you're cutting out some of the fibre. We don't see a huge difference. So it's kind of, yeah, it's a hard one to to measure because of the absorption. And I guess that's this 9-metre digestive tract, right? It's it's long and it's all different parts of doing different things and it's hard to, you know, obviously they're now looking at, um, you know, pills which can measure the pH at certain parts of the gut and get more insight mechanistically to what's happening.
Dr Rupy: Is that like an encapsulated endoscopy where they you literally swallow it and it sends messages via Bluetooth or something?
Dr Megan Rossi: Yeah, they call it a smart pill. We've used it in some of our clinical trials. Um, and it yeah, exactly that, you have to wear this, um, monitor and it senses it and it kind of gives a reporting of the motility, you can see how it's moving and also the pH and and stuff like that.
Dr Rupy: That's super cool.
Dr Megan Rossi: That's definitely going to be turned into a wearable one day.
Dr Rupy: 100%.
Dr Megan Rossi: And then in terms of objective measures. So we're talking about the probiotics and these specific strains, it sounds like the uh studies are looking at symptoms, like the livelihood of diarrhea in the case of antibiotic-associated diarrhea as an example. Are there any objective measures where we can actually measure the the biome by a stool and actually show, "Okay, when you've taken this probiotic, it's either harmonized or crowded out some of those pathogenic bacteria that you find in, um, in in in your in your guts?"
Dr Megan Rossi: So there are studies that show that the bacteria survive and increase in number, but they've specifically because they've been part of the probiotic study, shown that that strain, so that was their focus. They didn't really measure other microbes, I am aware of. Um, and obviously there's, you know, so many things we would love them to measure, but obviously it is, it's an expensive thing, right? To be like, "Okay, has that changed the diversity?" And I guess, you know, that's one of the things we don't typically see a probiotic changing is microbial diversity, which is why we don't recommend it for general gut health. Um, but it does specifically, you know, grow that. Most of the studies for most of the different types of strains, again, it will differ by strain, I suspect, by about 14 days, that strain usually dies off. So very few strains are thought to then get in there for life. And it depends on the individual as well. Like some individuals with really resistant microbiomes, unless you're dosing regularly, um, then then the other ones will fight it and then it'll die off. Whereas other ones might have a little niche and then those get in there. Okay. Um, so yeah, it's it's a really interesting space and I think there's this whole level of personalization that will come, but we're just so far away from that. So it does frustrate me when I see companies being like, "I'll test your microbiome and then give you the probiotics you need." I'm like, "I wish. I would be signing up for that."
Dr Rupy: Do you think we'll ever get to that point?
Dr Megan Rossi: I maybe in like 30 years.
Dr Rupy: 30 years? 30 years.
Dr Megan Rossi: I know, we'll we'll be in the nursing home being like, "God damn, I wish that one was going." Because it is just so complex. So just thinking about the microbiome, right? So we're always focused on the micro the bacterial component, right? Um, but there's also a virome, a virus component and there's a mycobiome, the fungal component. We've hardly touched the research and there's also the parasites. Um, some of which are thought to, you know, synergistically work together. So there is so much we don't know and then a lot of the bacteria we don't even know the name of, we haven't sequenced. They're living in us and doing stuff. Yeah. So if you put, you kind of take that into the picture, you're like, "Okay, yeah, it'll be probably 30 years." And also working in the research space, I see that like our, um, food emulsifier study, adapt, we, I think we got the grant seven years ago and we've only just published. And it was just at a conference. We haven't even finished publishing like the peer-reviewed final paper, seven years. So it's like things take time because it's you got to recruit, you got to do everything, get ethical approval. Um, so yeah, good research annoyingly is slow-moving, hey?
Dr Rupy: And and a silly question for me. So some of these gut tests, do we actually have, um, maybe not commercially available gut tests, but any gut tests in the research setting where we can map the virome and the mycobiome and and the parasite, do you call it the parasitome? Is that a thing?
Dr Megan Rossi: Yeah. I probably pronounce it wrong, but that's what I'm going with. Um, so different research groups, I think, will look at the at the different types. Like our research group that we work with, um, in Paris who's doing the adapt analysis, they don't look at the virome or the mycobiome. I think there's just a few research groups like who've got the technology to kind of look at that. Um, and also I think, you know, when we think about the microbiome test, it's also important to think about actually a lot of it will come down to not who's there, but what they're doing. So like you and I could have the same microbes in our gut, um, but if you eat a certain way or do certain things, your microbes could act different, produce different metabolites than mine. And we did a study at King's where we looked at trying to predict the response to a a low FODMAP diet, and we looked at the microbiome, and the microbiome didn't necessarily give us the answers, but the volatile organic compounds, so the the things the bacteria were doing, chemicals they were producing gave us a better predictor of who would respond and who didn't. Got you. Okay. So again, it just kind of highlights how complex this whole world is. And I think we will get there, but it just there's a lot to do and a lot we don't know yet.
Dr Rupy: So, yeah, if we're using like an analogy like a football team, like you can have one team that's got like a Portuguese striker that's incredible and like a goalie from Brazil, and that might look like a completely different team to another one, or maybe they look the same. Maybe you've got the same Portuguese striker, but from a different area of Portugal, and then that same, but then the results of those two teams when they play can be completely different. So you might be looking at a snapshot of a team that looks the same, but the outcome is completely different.
Dr Megan Rossi: Yeah. And that I love the football. I mean, I'm sure everyone listening will will love it if they're a male and into it. Um, sexist, I know. A lot of my females do like it, but I am not one of them and my husband loves it. So he will will uh enjoy that. Um, so yeah, I mean that's the whole concept of this personalization thing, but I I want people to not be overwhelmed by that and at the moment, appreciate that we're still very much at we just want to know what's good for most like, you know, the general person. Like generally speaking, you know, we see through all the clinical data that the Mediterranean diet, um, is the one that will help us live the longer, all the different plants and you know, fermented dairy, all that sort of stuff. Um, versus I think, you know, this whole space of quinoa is better for me than buckwheat. We just aren't there. I want us to be there, but like there's just so many nuances to that. So I think I don't want people to, you know, go, "Oh my god, this is all just too overwhelming. I don't even know what to eat." I'm like, actually all healthcare professionals agree, like Mediterranean diet, extra virgin olive oil, those sorts of things. That's what, you know, will lead to a longer life. And there might be small little nuances between the individuals. Um, and we will know more in like a decade, but like let's just temper that until we kind of have that convincing science.
Dr Rupy: Yeah. I mean, from my perspective, just from what you're talking about, and we're in the sort of hypothesis territory here, I'd admit, but um, I'm less interested in who's there and I'm more interested in what the outcome is. So this idea of metabolomics, so the these compounds that they're producing, the metabolites, like is that do you think where the money is going to be where the puck's going in the future? Where we should be more focused on?
Dr Megan Rossi: 100%. Because I think a lot of the bacteria probably can act very similar. Um, so it doesn't necessarily matter if you've, you know, got too much of this one or too much of that one. If they're doing the same functionality for your body, happy days. Yeah. Um, and you can, I assume, achieve very similar outcomes in terms of those metabolites with different diets. So like, you know, a Mediterranean-flavoured diet versus an Indian diet that's like more heavy on the lentils and and whole wheat and stuff and breads, but you're you're still like producing very healthy outcomes.
Dr Megan Rossi: 100%. And I think that's why, um, this is a lot of 100% coming from me. I'm feeling really alive. Um, but I think that, uh, yeah, I mean, it it definitely makes sense and why all the scientists are saying there is no one healthy microbiome. Do you know what I mean? Like, an individual will have their healthy microbiome with the most diverse and stuff, but we could both have like amazing microbiomes that look quite different because it's about the functionality, I think.
Dr Rupy: Okay. And in terms of like how you might approach someone who has a low-carb preference, let's say, like would you be super worried that they're restricting uh certain elements of their diet or do you think it is achievable to have the similar outcomes with a dietary preference that might be lower in in whole grains?
Dr Megan Rossi: Look, I think absolutely it's all about the individual. Right? I think it's so ridiculous to be like, "Everyone needs to have three serves of whole grains and stuff," like because no, even if we've got data to suggest that might be healthy for the individual, if they don't enjoy the taste or they don't want to do it, they're not going to do it. And therefore, if we're giving them strict advice, they'll just rebel and go crazy and gung-ho and stuff. What I would say is that we do see that each different type of species, um, plant species, particularly different groups, I call them the super six, everyone's called them different things. But you've got your whole grains, your nuts and seeds, your fruit, your veg, your legumes, so chickpeas, beans, and your herbs and your spices. And actually each different kind of category does contain slightly different polyphenols and foods like that. So, um, there was a great study from, I think, Bergen University or University of Bergen, um, and what they looked at was those kind of different super six and how much extra years they would add to your life. And they showed that legumes had the greatest impact in terms of, I think it was like two and a half years of additional healthy years to your life, um, and had a greater impact than like fruit, for example. Um, and again, that's not to say that the legume fibre is more protective, it's probably just because it's an easier win and most people aren't having legumes. So I guess my take home from that is that each different category and they looked at nuts and whole grains as well provides different things. And therefore, you don't need to go and have a whole load of whole grains and carbs if that's not what you want to do. But worth thinking about, "Okay, well if I'm not having any grains, what nutrients am I missing?" A lot of people miss things like fructans. And there's all different chains of fructans, like they're prebiotics for those who are who are unaware of that. Um, and there's all different chain lengths or all different types of the fructans. Um, so it's just thinking about what's the ramifications of that. And I guess it feeds into, you know, the demon of gluten, um, where they've shown that if people exclude gluten when they don't need to, i.e., they don't have celiac disease or non-celiac gluten sensitivity, then, um, they seem to have a a decreased in the microbial diversity. Not because gluten's some prebiotic and amazing thing, it's because they're cutting out barley, wheat, um, and rye, which contain those fructans and other things. So it's always often consequences, as I was going to say, of of cutting things out.
Dr Rupy: This has been great. Thank you so much. I think we've covered a lot on probiotics, you know, how to determine whether you need them, what to look for, looking up those strains. It does feel, I think, even for me, like I need to have a PhD in probiotics to actually decipher uh which one might be appropriate. And I guess for for folks at home, you know, some of these websites that we've alluded to and some of those areas from the World Gastro Organization would would be would be useful. Are there any specific people who really should steer clear of probiotics? Is there any evidence to suggest that they could be doing untold harm?
Dr Megan Rossi: Yeah, I think it's a really good question. So I think anyone with a, um, a suppressed immune system needs to be cautious. But actually, again, it will come back to the strain. So there is some, um, clinical trials showing that the LGG strain of bacteria can help, um, prevent specific types of chemotherapy-induced diarrhea. So safety profile has been, you know, shown in that scenario. Again, I would, you know, as a healthcare professional, I put that forward to the team and be like, "Okay, well, what chemotherapy are they on?" All of that sort of stuff. But I would be always careful if your immune system's suppressed in any sort of way. I think if you've recently had a gut, um, gut surgery, bariatric surgery, something like that, I would just be again, just mechanistically, if the gut's like super permeable and healing, I probably would want to wait three months. And again, then be very specific about the strain and make sure it kind of aligned. So for me, that's and then obviously the preterm infants, like I said, but again using where there is evidence. Um, I would always want to make sure like if you are pregnant, um, then again, the the strains have been approved, um, you know, are safe during pregnancy. So, um, yeah, so for example, the Lactobacillus GG and BB12 both been approved as safe in pregnancy, that vaginal formulation safe in pregnancy, which is good obviously because things like thrush and BV are heightened during this period. So, um, yeah, you just need to check essentially.
Dr Rupy: That's brilliant. Um, quick hot take on GLP-1s. That's coming up from from a proper left field there. What's going on with the gut?
Dr Megan Rossi: Yeah. Well, I mean, we know that the microbes help stimulate the gut to produce GLP-1s and the short-chain fatty acids when we eat the fibre, that's one of the mechanisms of how fibre gives us that satiety effect, right? Yeah. Um, I mean, I think in terms of the drugs out there, one of the dangers, like I am, every individual can do what they want, right? I would say one of the dangers that we need to be careful of is people go on them and, you know, it works well obviously by just reducing down the appetite. So they're just having half a croissant, half a Mars bar, that sort of stuff. So actually they become really malnourished. So they can still be bigger in a size, but not getting any of the fibre because they're like, "My tummy won't fit that in anyway, and I don't want to be more full." They're not getting any of the micronutrients, polyphenols, all of that sort of stuff. So it can be done very dangerously, but it can be done really beneficial. I'm sure you've seen in clinic, you know, if you have a someone who's really struggling who's got, you know, really high BMI and they just need that little helping hand to be like, "You know what, I can do this," and then get that motivation to see some of the weight coming off. Then they're more likely to feel comfortable in the gym, you know, eating healthier food because they're motivated. But they need to be counselled through that, right? So I'm, I don't know if that's something that aligned with you, but yeah, so I can see it as both sides.
Dr Rupy: Yeah, I know, 100%. I definitely see that they're here to stay and they're getting better and better, I think. And I think the results are phenomenal from a from a weight point of view, but I think what I worry about is the abuse and the cycling and the fact that all the studies are done with healthy lifestyle intervention as well. And I think a lot of people forget that. And it's sort of been touted as a magic pill. In fact, um, Johann Hari was on the podcast last year who's been on Ozempic for a year, wrote his book, "The Magic Pill", and this is literally how people see it. And I think it really needs a reframing. So if you are going to take it, uh I would highly recommend getting lifestyle interventions, exercise, muscle, protecting your muscles, protecting your fibre and protein intake. These are all things that should be sort of caveats and and sort of sold with the the product as well. It should be an adjunct.
Dr Megan Rossi: So yeah, and I think a lot of reputable practices now are making that as part of it. So the medics and the dietitians are working together. Um, so I know the gut health clinic girls are now part of a medical pathway where they, if someone is going to go on it, they have to see the dietitian. which is not always easy because they're like, "I'm being forced to see you." But at least, you know, the pathway is there to be, you know, protecting. But obviously there's so much being sold online and stuff.
Dr Rupy: Yeah, yeah, totally. Thank you so much. This is great. I feel a lot more educated on probiotics and I I really hope my listeners are a lot clearer about what is a really complicated area. So I really appreciate your time.
Dr Megan Rossi: I've had a ball. Thanks for having me.
