Dr Rupy: Babies' gut microbes when they're exposed to these through milk oligosaccharides, it actually helps to shape their immune system, but it also can help shape their metabolic health as well. And what's really amazing about human milk oligosaccharides as opposed to animals is that there's such a huge diversity of human milk oligosaccharides. We have a diversity in humans that is unparalleled.
Dr Rupy: Welcome to the Doctor's Kitchen podcast. The show about food, lifestyle, medicine and how to improve your health today. I'm Dr Rupy, your host. I'm a medical doctor, I study nutrition and I'm a firm believer in the power of food and lifestyle as medicine. Join me and my expert guests where we discuss the multiple determinants of what allows you to lead your best life.
Dr Rupy: Allergy is on the rise. It affects one in five adults and the rise in children is astonishing. One in three will suffer asthma, one in six will suffer eczema and there has been a huge rise in food allergy now affecting one in 13 children, including a five times increase in peanut allergy. All this brings a huge amount of disruption to people's lives, fear and the rising wait times for allergy clinics is a well-known phenomena. And working as a GP and in A&E, I have seen thousands of children with issues and that's why I really wanted to talk about what things we can do to prevent food allergy using the research available today. So Dr Vincent Ho is my guest today who is a clinical academic gastroenterologist and senior lecturer at the School of Medicine, University of Western Sydney. He's also a practicing gastroenterologist and more recently he published The Healthy Baby Gut Guide. And when it came across my desk, I thought that this book was packed with sensible advice. Vincent has laid out the studies in a really easy to understand way and there's a dietitian approved nine-week infant meal plan to help you navigate the introduction of foods for your baby, which I think is essential reading for every parent and parent to be because I think having that structure is really, really useful. There's a lot to cover today, but by the end of this episode, you should be able to understand the concept of immune tolerance and the hypotheses behind why we see a rise in allergy in general, why early exposure to common allergenic foods is key and also the genetic and environmental links between allergy, including the uncomfortable topic of BPA and phthalates as well as other environmental pollutants. What the first thousand days refer to and why this is actually critical for supporting a normal immune system. We talk about how maternal diet impacts food allergy, the evidence for supplements such as fish oils, probiotics and vitamin D for mothers. We also talk about the benefits of breast milk, probiotics for children and a diverse diet for kids as well. How to introduce known allergens into your baby's diet from six months in a systematic and safe manner using an anti-allergy meal plan. I think this is perhaps one of the best practical take homes from the book as well. And we also talk about the future for allergy therapy. It's a fantastic episode and if you're looking to get pregnant or have a high risk for allergy, I think this is highly recommended listening and if you do know anyone, then I would highly recommend you share it as well and just spread the love and the message as well. This is going to be hopefully a wonderful resource for you guys. I'm doing a new thing every single week, which is our podcast recipe of the week. A recipe that reflects the topic of conversation on the podcast and this week it is the crispy black bean bowl. You can get it on the app right now and you'll also get it in this week's newsletter as well if you're a subscriber. You can just look it up at thedoctorskitchen.com. The reason why I'm adding this recipe is because a friend of ours is actually going through the weaning process and they're cooking for themselves, but they're also splitting up the ingredients that go into their meal into a simple mashed version for their child as well. And it's a lovely sight to see. I mean, obviously the recipes aren't made for weaning, but looking at the individual elements of this, bit of avocado, bit of black beans, bit of greens there as well, just loads of different elements that they can choose on a smorgasbord in front of them. So there's actually a picture. I'm hopefully going to show that on social media as well. So you'll see what I mean. But yeah, I thought I would share the crispy black bean bowl as the podcast recipe of the week. And don't forget, you can download the Doctor's Kitchen app for free to get access to all of our recipes with a seven-day free trial. We add recipes every single month and we've had some amazing feedback so far and new features being added all the time. You're going to hear about those on the podcast too. And do check out the newsletter where I share something for you to eat, read, listen to or watch every way. There's some mindfully curated media to help you have a healthier, happier week and you can go check that out there. Awesome. The links to everything are going to be on the show notes at thedoctorskitchen.com. But for now, here is my podcast with the wonderful Dr Vincent Ho.
Dr Rupy: Great. Vincent, so, so good to have you here. I'm so glad we got to do this. Unfortunately, we couldn't do it when I was in Sydney, obviously with COVID and everything going on, but I'm really glad that you've got some time to jump on the pod today.
Dr Vincent Ho: Hey, thanks Rupy, that's fantastic. Yeah, thank you for having me on and I'm really passionate about talking today. This is a topic really dear to my heart.
Dr Rupy: Yeah, absolutely. I I actually I I read at the end of the book actually whilst you're closing that this book was really the product of something that happened five years ago in your storyline with your your lovely daughter in a Chinese restaurant. I wonder if you could tell us a bit about that day and and and how that's led to to what you do now and ultimately this book as well.
Dr Vincent Ho: Yeah, Rupy, it was a day that is very memorable to me because it was a day that I felt I almost lost my my daughter. So Olivia is now six and this was about five years ago when she was six months of age. And we were in a Yum Cha restaurant and one of the things you eat at Yum Cha towards the end of it is an egg tart. So it's a delicacy that we have. I'm sure you've tried it Rupy, the the the beloved egg tart. And we fed her a bit of that egg tart. Now we hadn't given her egg before, we thought it would be safe. And then within a few minutes, she started getting a reaction. So she looked very distressed. She had a skin reaction. She looked like she was very uncomfortable. I felt she wasn't breathing very well. I was really concerned that she was going into anaphylaxis. And you know, Rupy, we are medical doctors and we have when we're managing patients, we have all the resources behind us. We've got emergency, we've got all the equipment behind us. But when you don't have that, when you're there with your family, you've got nothing, you actually feel helpless. You've got nothing. There's no, there's nothing. There's just no medical devices, there's no medications. You feel helpless. And I've never been that helpless in my life. Like I think I remember days when we'd seen patients coming in from trauma, stressful cases of anaphylaxis, other cases, but we would manage that in the confined setting of emergency. We're very planned, deal with it. But then and there, I I I, you know, I will admit that I freaked out. I I was very, very scared and I called out for an EpiPen, but of course, you know, you're in a restaurant, no one's got one. And so we decided to, because I was so afraid, I put her in the car, drove her to hospital. I didn't want to even call for the ambulance, got her straight there for emergency. And fortunately by the time that she got there, the reaction seemed to settle. So it was it was good. Then we got her reviewed later on by an immunologist and she was diagnosed as a formal allergy, an egg allergy. And so that led me to really that encounter led me to really investigate childhood allergies. And then I realized the connection between childhood allergies and the gut. And you know, I can tell you there's an amazing story to tell there.
Dr Rupy: Yeah, yeah, absolutely. Two things. A, I really respect the fact that you're authentic and vulnerable enough to say, you know, you freaked out because I've been in similar scenarios outside of clinical settings and you do, you know, there's not that nurse that you can call and and you know, you don't have hands on deck, there's no other doctors to help you with a an emerging situation. And also when it's your loved one as well, it it heightens your anxiety. It's a it's a very uncomfortable feeling and scenario. So that I mean, I I really respect you talking and sharing about that story. And then the other thing is this will resonate with so many people because so many people today, as you eloquently talk about in the book as well, have children with allergies or allergies themselves as well. And we're just we'll we've seen this huge rise over the last 15, 20 years. I wonder if you could speak to the numbers and maybe we could dive into some of the hypotheses as to why this is happening and and obviously as you've alluded to, it really does come down to a lot of gut health related theories too.
Dr Vincent Ho: Yeah, so allergies is a growing problem. It's actually becoming an epidemic. And I will say that if you look at the figures behind allergies, we know that about 30 to 40% of the world's population right now is affected by allergies. I mean that's just simply a staggering figure. And what's interesting about allergies is that the incidence of allergies has actually increased by about two to three fold in industrialized countries over the last three decades. And it's estimated that about four billion of the 9.7 billion people that will have by the year 2050 will have at least one allergy. So the scale is huge. And I can tell you that in Australia, children and allergies is a big issue. As an example, we know that about one in 10 children in Australia will have a food allergy and that's been shown in one study that was published out of Melbourne a few years ago. So it's a huge problem. Now, as to what we can do about that, we've got to realize that there are a number of forces at work here and certainly the environment does play a role. The hygiene hypothesis is a popular hypothesis that's been bandied around a lot. And in fact, this hypothesis actually comes from the United Kingdom. Yeah. It came about because a professor, David Strachan, who he's a London epidemiologist, and he published in the BMJ this survey, this was back in the late 1980s, of about 17,000 British children. And he wanted to find out why there was this increase in the incidence of hay fever in post-war Britain. Now, what he found was very interesting. So he found that the more older siblings a child had, the less likely he or she was to develop eczema by the age of one or hay fever by the age of 23. And so Professor Strachan recognized there was some protective effect that the older siblings were passing on to the younger children. Now, I mean, Rupy, you know, certainly listeners will recognize that especially if you've got children, they can be quite feral when they play, right? They can tear one another. And along the way, lots of microbes are being transmitted. So Professor Strachan felt that maybe this special protective effect was actually exposure to microbes. And it was thought that early exposure to particular microbes could protect against development of allergies by affecting the development of the immune system. And this is what the hygiene hypothesis is all about. So what an interesting hypothesis. He published it and it was interesting when he published it because the term hygiene was only in the title of the paper. It wasn't actually in the paper at all. It was in the title, but the media just loved it. You know, it was just this theory about, you know, this hypothesis about hygiene and and people felt that, you know, you had to be exposed to lots of bacteria and bugs and get dirty and that was what was needed to protect against allergies. And it's actually not strictly true, Rupy. I mean, you shouldn't basically disregard personal hygiene. You should actually do all the right things, clean your hands, of course, because that's not what the hygiene hypothesis is about. It's really about the fact that if you get exposure to these microbes, and these microbes that he's talking about and later on there's been other amendments to the hypothesis, these microbes have been around for a long time, what we call old friends. So these old friends microbes have been around for a long time and by getting exposure to these microbes early in life, it can actually help to change our immune system in such a way that it can help protect against allergies.
Dr Rupy: Yeah, yeah, absolutely. I I wonder, so you've nicely described there the two sort of dominant theories that I think most people have heard of, the the hygiene hypothesis. And it's very interesting to note that that was just in the title, yet the media just latched onto that as a term. And then the the old friends theory. I wonder if you give us a a basic immunology lesson in terms of how balancing of those T helper cells actually leads to allergy and and leads to protection as well and how they can how they communicate with each other.
Dr Vincent Ho: Yeah, so classically we're talking here about TH1 and TH2 imbalance. So just to explain, TH1 cytokines are really those, um, the best way to put it would be pro-inflammatory. So they're really in favour of inflammation and these are molecules that are designed to kill off bacteria that get inside our cells and they can kill off viruses, really important. But we know that if you've got too much inflammation, then that is going to cause a lot of tissue damage. You won't just cause damage to your bacteria and viruses, it's going to kill a lot of your cells. So the body has to have a way to counteract against it. And this is why you've got TH2 cytokines. So TH2 cytokines actually help to counteract the TH1 response. Um, what I will say is that they're particularly good at fighting off parasites such as worms that are located outside our cells. Now, a lot of these TH2 cytokines are anti-inflammatory, but the trade-off though with having a very vigorous TH2 response is that it can actually promote allergy. And this is where the TH1, TH2 cytokine, um, that that's a that's a mechanism that's been proposed to explain the hygiene hypothesis. So there are some factors that can really favour a TH1 response. So for example, presence of older siblings, we talked about, early exposure to daycare, um, if you have household pets, childhood infections, um, exposure to a farming environment. These are things that are going to favour TH1 response, moving away from TH2. On the other hand, things that favour a TH2 response include the widespread use of antibiotics and a more industrialized, like a more industrialized lifestyle. So TH1, TH2 is an important part of the explanation for the hygiene hypothesis. But I will say that's not the full story behind allergy. There's a bit more involved there. For example, you've got T regulatory cells that can help dampen down that allergic immune response. But I think it's a quite a good concept, the TH1, TH2 imbalance. It's a good concept that we can build upon.
Dr Rupy: Yeah, definitely. Not not to derail our conversation too much because I think we can go down a rabbit hole with this, but considering what's happened over the last couple of years and what we just mentioned about how early exposure and even going to daycare early can help develop immune responses and a more tolerant immune system, would you expect us to have worse allergies within kids considering we've pulled them out of nursery and daycare and that kind of stuff over the last couple of years because of the pandemic?
Dr Vincent Ho: Well, look, I think the answer is it's quite likely. Um, the reason for that, Rupy, and obviously we need more data on this, is that exposure and certainly for young children, contact with other young children, some of those microbes, um, is is actually important and protective, it favours the TH1 response. Now, if you've got an environment like with COVID and the social distancing that goes on, um, parents don't want their children to to to mingle with other children, they're keeping their children in a very sterile, sanitized environment. You can imagine that actually is going to lead to more allergies. And in fact, Rupy, I mean, I think we should watch this in the years to come, we'll see what the data shows. There could be an explosion of allergies as a result of all this social distancing that we're seeing with the with COVID-19.
Dr Rupy: Yeah, absolutely. Um, it would definitely be one to watch. I'll be I'll be fascinated to see what how we can counter that as well with with um, other sort of public health measures to to encourage immune tolerance. Um, obviously genes has an impact as well, you know, these allergies have a run in families. And then you also mentioned environmental pollutants that I wanted to touch on as well. Um, can can we speak to those? Do we do we know a lot about the genetic component now?
Dr Vincent Ho: Yeah, so the genetics is really, really quite important. And I think when we talk about genetics, we've got to find what actually is high risk because high risk for allergy has a very specific definition. So I think in in talking about high risk for allergy and certainly this is applicable when it comes to all the all the trials here, we're really talking about the big four allergies here. So the big four allergies are eczema, food allergy, asthma and hay fever, which is also known as allergic rhinitis or allergic conjunctivitis. So essentially, if you are a child that has a parent or sibling that has one of those big four allergic diseases, or if you as a child already got a history of one or more of these allergies, then you are at high risk. So as an example of that, because Olivia had an egg allergy, then her younger brother Brandon is at high risk of developing an allergy. Um, also, um, if you've had an allergy, let's say you've got eczema, then of course you'll be at a greater risk of developing other allergies like food allergy. And that's really important, Rupy, because um, researchers can look at at a population at risk. For example, they can look at children that are that are likely to develop other allergies because they've already have a pre-existing allergy and they can study them and look at look to see whether the interventions that they're testing can reduce the rate of developing those allergies. So I think that's really important in terms of defining high risk for allergy. And obviously, we know that there is a genetic tendency to develop allergies in many of these children and we call that atopy. So atopy is that genetic tendency to develop an allergy. And believe it or not, it actually has a lot to do with this TH2, TH1 response. And the reason I say that is we know that after birth, the TH2 reactivity, it actually dampens down in infants that go on to show no evidence of allergy. So those that are non-atopic, the TH2 reactivity goes down. Now, we know that um, in a lot of in a large proportion of infants, the TH2 reactivity can remain elevated, persist for a few years, but eventually dampens down. However, there is a group of children that are atopic that are going to have a persistent heightened TH2 reactivity for years and years and years. And those are the children that are at great risk for allergies. They're the children that have a very significant, profound allergic reaction, anaphylaxis. So there's there is a big linking the immune system to genetic risk.
Dr Rupy: Yeah, yeah, absolutely. And um, you talked a bit about environmental pollutants here. Now, this is a tough one to talk about because it's just so pervasive in society today to have BPA and non-BPA products that might still have issues, phthalates. And I think if we were talking about this maybe like five, 10 years ago, there would have been a lot of eye rolling. But now, I think it's becoming a lot more understood about what these impacts can have, certainly on metabolic health, but I was I was quite surprised to hear about this and its impact on allergy as well.
Dr Vincent Ho: Yes, Rupy. So we know that many of these pollutants that you mentioned, um, pesticides, solvents, they um, they they actually can modulate the immune system. So they tend to decrease the TH1 response, but they can also enhance the TH2 response. And as I mentioned before, you need that TH1, TH2 um, cytokine balance. So for example, cigarette smoke, um, you know, that decreases TH1 activity and it's linked not surprisingly to a higher risk of allergy in children and unsurprisingly asthma. So we know that. Children that are exposed to diesel exhaust particles, um, it tends to, interestingly enough, support, it supports more TH2 hormonal messaging cells. It tends to stimulate those cells and it supports a switch towards TH2 and a TH2 immune response. And we know, as you've mentioned before, that things like BPA, um, phthalates, of course, um, they play a role. I mean, phthalates themselves can induce TH2 activity. Um, and organic solvents, another big one too. So organic solvents, um, you get that of course in a lot of products. You get that in paints, you get that in cleaning products, you get that in um, glues. And we know that with children that are exposed to a lot of these solvents, they have found they've got an increased TH2 response and they tend to be more likely to respond to milk and egg whites. So that's been shown in studies. And finally, of course, herbicides, pesticides, well, you know, there's been a lot of good data about that too. There was one big study from California that actually studied school-aged children that were exposed to pesticides or herbicides and actually found that um, there was a uh, a noticeably elevated risk in the development of asthma and in fact, when it comes to herbicides, the risk of developing asthma was increased four and a half times. So fairly significant.
Dr Rupy: Yeah, yeah. This is really significant. And I I guess like, you know, your experience, you've you've had a child, you've had that horrific experience of a known allergy. When you hear about these things and obviously you're doing a deep dive into the research as well, how do you balance health anxiety with being pragmatic about, you know, what can lower the issues with your child? Because I think a lot of people listening to this will be like, I need to clean my entire house of all these products. I need to make sure I only eat organic. You know, there's got to be a balance with this stuff, right?
Dr Vincent Ho: Yeah, look, I agree. And we've got to be practical about that. So for example, um, you know, many water bottles now are BPA free, and so that's a good thing. Um, avoiding exposure early in life to some of those organic solvents, for example, paints is sensible. Um, I think that we've got to be reasonable about the advice that we give. So, you know, I think it's common sense to say that cigarette smoke, avoiding that, um, is going to be beneficial not just for allergies, but for a whole range of reasons, health reasons too. I think when it comes to pesticides and herbicides, um, it can be difficult, um, to give specific guidance about that because often we don't know whether the products that we're consuming have been exposed to pesticides or herbicides and um, and I know that there's been an industry now which has developed around organic, um, and pesticide free. I'm not necessarily saying that we should we should be um, going for foods, for example, that are that are totally pesticide free or herbicide free. I mean, I realize that at a practical level, um, people need their, you know, need their vegetables, they need their fruits. Um, so that's important. But I think that wherever possible, during at least during the first years of life, it's good for your very young children to avoid exposure to some of those environmental contaminants that are that are very obvious. So things like cigarette smoke, avoid exposure to paints, for example. Um, water bottles, if they're BPA free, that's that's ideal. Um, so some of those practical things, Rupy, are good. And don't forget, of course, there are things that we can do to help reduce their risk of of allergies as well. So even though there are things that are increasing their risk, there are things that we can do to reduce their risk.
Dr Rupy: Yeah, absolutely. I think that that leads on quite nicely to what I wanted to ask you about, which is the thousand days and perhaps you can introduce us into the 1,000 days concept when that starts at the moment of conception and why this is so important when it comes to allergy. And I think again, within the context of not giving people too much health anxiety, you've quite nicely talked about how there is a lot of external pressure as well as internal pressure from mothers in particular about what they should be eating, what they should be feeding their child post-partum as well. So I think that within the context, you know, we want to be sympathetic to people and I think I think you you tow that line very well in the book too.
Dr Vincent Ho: Yeah, Rupy. So, look, I think to to understand um, the first 1,000 days of life and why it's so important, I think we can go back to a hypothesis that has been talked around a lot. It's called the dual allergen hypothesis. And really that's the idea that if you um, uh, if you sensitize, for example, I'll I'll guess if we use food allergy for example, if you sensitize somebody to skin, so a low dose allergen to skin, it tends to to trigger off um, an allergy, whereas if you consume that that food protein very early on, it induces um, oral tolerance. So oral tolerance is developed very early on. And people wondered, why is that? Why is it that when you get exposed to to to skin, um, that you know, even at a low dose, that's getting an allergy, whereas when you consume it orally, um, early on in life, it's important you're getting tolerance. Well, it comes down to this exact point, the first 1,000 days of life, what actually happens in the gut. So the first 1,000 days of life begins at utero, so it begins at conception. Um, so if we look at conception, we say it's nine months, on average, Rupy, that's about 270 days. So that's the first 270 days of that 1,000 days. And then after that, you have the next 730 days, which basically puts it just after two years of age. So that's when it goes. The first 1,000 days ends just after the child turns two. What is happening during that period? Well, we know that what's happening is that there's a tremendous amount of development which is going on inside the gut, um, both structurally, the gut's developing, but also the microbes within the gut are also developing. So very early on, there's this development phase, the um, bacteria are colonizing the gut, the baby's gut. And then after a while, there's this um, stimulation, this growth phase which occurs. And finally, there's this uh, phase and it's towards the end of the two years where we get stability of the gut microbiota. So we know now how important the gut microbes are, but towards the end of the two years, um, that's the time when the gut microbes of that child is fairly set. So it's very similar to an adult's. So there's a lot happening between, especially in the first year of life, a lot is happening, but by the end of the two years, things stabilize quite a lot. And that means that if we want to address um, we want to make some changes that can affect the immune system, the the idea of making some changes in the first 1,000 days of life, particularly early on in that time is probably the key time. So interventions in the first 1,000 days of life have the ability to really shape your gut microbes for the future.
Dr Rupy: Yeah, yeah. This is I mean, this is fascinating stuff. And I think um, I remember reading uh, externally from your book as well as in the book as well about the trimester uh, transfer of maternal antibodies and how maternal diet can also shape uh, the microbiota of of uh, the child as well or in utero. Um, I wonder if we could talk a bit about those studies that have looked at specific elements of the diet and how that has impacted either positively or negatively uh, the likelihood of allergy uh, um, post that 270 days.
Dr Vincent Ho: Yeah, so, um, look, I think it's there are I guess the good news is there's a lot of studies. There's a lot of studies out there and it's really quite exciting because there have been studies which have been done on pregnant mothers and in fact, there's one study that I do want to talk about. It's a one that was done in Massachusetts. This was a study that had over 1,200 mother-child pairs. And what they did during this study was they found that um, they were recording the information about the mother's consumption of various foods. And what they found was that the mothers that consumed high levels of peanuts, milk and wheat during pregnancy, um, early pregnancy in particular, was associated with reduced reduced chance of childhood allergies, especially asthma. So the important thing was that the exposure to those allergenic foods happened early during pregnancy. And this is a concept that we're going to go back to again and again, Rupy, intervening early. So the researchers found the window of time in which women ate these risky foods was vitally important. In other words, the first trimester, they felt was a very key time for the development of the unborn baby's immune system and the creation of tolerance to that allergen. So tolerance is the concept that the um, immune system, the baby's immune system recognizes this foreign substance and adapts to it. It doesn't have a uh, an allergic response. It's not an inflammatory response. It recognizes it, um, and um, recognizes it as a um, a substance which it regards as quite safe. And so it's learned to learn to live with it. So that's what tolerance is all about. So the idea then is that if food allergens are exposed to mothers early during pregnancy, then that can potentially lead to tolerance rather than sensitizing them to allergies. So that was one really interesting study during pregnancy. Now, there was another big study and it's come out comes out of Europe. It was a great study here. This was the PASTEUR study, which was published in 2012. And this followed over 1,000 children that were born to farm and non-farm mothers. So what I mean by that is mothers that spent time on farms and ones that didn't. And they followed them for five years. Love the study. Yeah. Great, great study here. Um, and what was interesting about this study, Rupy, was that they found that if you were exposed to a farming environment during pregnancy, that was associated with a reduced risk of asthma in children. So it was a fascinating one here. And we know that farming environment, lots of bugs, microbes, um, and it was such an interesting study that that people to recognize there was something about the farm environment that was protective. What was that um, factor? Um, well, it turns out that one important factor is endotoxins. So it sounds like they're very bad for you because it's like toxins, but actually endotoxins aren't actually bad for you. They're actually found naturally in farms. Um, you find them a lot in farm stables where you find livestock and poultry. And the thing about these endotoxins is they actually help to switch your immune response to a TH1 pattern. Uh, and um, there was one other big study that was done called the PARSIFAL study, and that study was fascinating because that study studied again mothers that were that uh, were on a farm and they found what they they looked at what they did to reduce their risk of developing um, allergy, the risk of allergy in their children. And they found that the single most important protective factor for these mothers, um, was actually exposure to a a farm stable environment. So in other words, if they were exposed to farm stable work, and it sounds really crazy out here, but if they were exposed to that, then their children would have um, a significant reduced risk of allergy. That was the single most protective factor in that big PARSIFAL study. It's fascinating. Yeah.
Dr Rupy: Yeah, absolutely fascinating that. It sounds to me like, um, so over 10 years ago when I first became a doc, um, there was the pervasive belief that we should be avoiding allergic foods within the maternal diet. Uh, but now it seems like we've, you know, we've completely changed that and we're actually encouraging not just inclusion of those uh, uh, potential allergens, but early inclusion. So the timing of when we eat these foods sounds to be quite critical.
Dr Vincent Ho: Yes, that's absolutely right, Rupy. That's indeed been a paradigm shift, a significant paradigm shift when it comes to, as you've said, in pregnancy, it's no longer about avoiding allergenic foods, but it's rather getting exposed to those foods early on to develop tolerance. And we can talk about this later, but also when it comes to young infants too, about them also getting exposure to these foods, allergenic foods early in life. So everything's switching off to early. If there is one concept that I want to impart to your listeners, it's about getting exposure to these allergenic foods early.
Dr Rupy: Yeah, brilliant, brilliant. Um, and sticking on the maternal diet before we move over to uh, uh, baby. Um, supplements, fish oil, vitamin D and probiotics in during pregnancy. Uh, what are your thoughts on those and what does the research show?
Dr Vincent Ho: Yeah, so, um, look, I think that when it comes to, um, pregnancy, certainly vitamin D is very important. So if you're low in vitamin D, um, then you should get a vitamin D supplement. So it's always a good idea to do that. Um, now, omega-3 fatty acids, believe it or not, um, when consumed during pregnancy, they can reduce the risk of allergy in your in your baby. Um, that's been found in a number of studies. And we should be aiming for about uh, two servings of oily fish per week. Now, I'll make the caveat as well that when it comes to oily fish too, it does depend upon where in the world you're based. So some in some countries around the world, oily fish, there can be lots of mercury. So with that, there's a caveat about that. But certainly we would recommend around two serves of oily fish per week is is going to be good. Also probiotics. Um, this is a great one. So probiotics, yes, they are actually beneficial. So probiotics have been found to be helpful in reducing the risk of allergy when taken by a mother, um, during the last trimester. So certainly during the last trimester, during the last five weeks in particular, from 35 weeks onwards, it's been shown to reduce the risk of allergies. So there's a couple of important points I would emphasize. Um, probiotics, um, uh, certainly servings of oily fish, so you get your omega-3 fatty acids, vitamin D, and also don't restrict your diet during pregnancy and breastfeeding for that matter. It's important not to avoid, it's important to not to avoid these allergenic foods. Really important.
Dr Rupy: Yeah, that's super important. Um, do we know what specific probiotics? Because I'm always asked about what specific probiotics uh, they should be taking because as you know, and I'm sure it's the same in Australia, the plethora of different types of probiotics we have access to is is huge. Um, you know, and they all have varying concentrations and various claims about the number of colony forming units and live versus, you know, all that stuff. So do we do we know what specific probiotics um, that they've used?
Dr Vincent Ho: Look, I think, Rupy, that's where there is a lot of uh, I guess, um, dispute really because when it comes to probiotic studies, there's many different strains of probiotics. Um, so the we know that in general, these probiotics are very helpful. So there's some researchers from Imperial College who did this really large meta-analysis. This is about 28 trials and they found that, um, and these these trials covered over 6,000 pregnant women. They looked at a number of different probiotics. And that was important. I mean, most probiotics, as you know, will contain strains of lactobacillus or bifidobacterium. Um, but what they found is that it's not necessarily the type of probiotic, although, you know, I think there may be some differences between strains, but it's actually taking a probiotic, um, from about week 35 onwards that's found to be beneficial in reducing the risk of childhood allergies, particularly eczema. So it's eczema is the one that really is um, is where the benefit is. So I would suggest that rather than sort of looking at all the different studies, um, rather than, you know, crawling through lots of uh, of clinical research papers, I think just taking a probiotic, um, that's been recommended by their doctor, so by by their GP, starting from week 35 would be what I would would advocate for. I think we've got to be practical as well rather than delving into into intricacies. And we are actually finding, Rupy, that many of the probiotics are very similar, you know, in terms of effect. It's just minor differences in strains.
Dr Rupy: Yeah, yeah, yeah. It's it's I think it's definitely something that we have to refine in the research exactly, you know, and and like you said, in those meta-analyses, they use different formulations, different doses, different strains, and it's it's a wild wild west out there. Um, with breast milk and microbes, again, I want to be respectful for any listeners who can't uh, uh, produce breast milk or they can't breastfeed for for whatever reason. With what we know about breast milk and microbial transfer, as well as um, the prebiotics that are found naturally in breast milk, what do we know about how that impacts the post 270 days uh, in the thousand-day life cycle?
Dr Vincent Ho: Yeah, so a really good uh, question there. And you know, I will give a uh, I guess a personal um, account of this because my wife, Cindy, um, she couldn't produce much breast milk. Um, and this often happens during um, like after pregnancy that with the best of intentions, you just can't produce enough breast milk. So so you do require um, in some cases infant formula. And so that's just that's one thing that I guess we've got to acknowledge. But having said that, um, we know that breast milk really is considered the gold standard. So it's the gold standard because it is really what I would term personalized nutrition for the baby. So the baby wants nutrition and the breast milk interestingly adapts to it. Um, so it's dynamic, so it's constantly changing in response to the baby's needs. What's very interesting about uh, breast milk is that it contains um, lots of healthy proteins, of course, and contains um, lactose, but it also contains lots of healthy bacteria, so probiotics, and it contains interestingly enough, um, some special fibers called human milk oligosaccharides. So these special fibers, these human milk oligosaccharides, they're not actually food for the baby, but it's actually food for the baby's gut microbes. This is where it's so interesting. Um, the baby doesn't get nutrition directly from these special fibers called human milk oligosaccharides, but the baby's microbes do. Now, we know that when the baby's gut microbes, when they're exposed to these human milk oligosaccharides, it actually helps to shape their immune system, but it also can help shape their metabolic health as well. And what's really amazing, Rupy, about um, human milk oligosaccharides as opposed to animals is that there's such a huge diversity of human milk oligosaccharides. We have a diversity in humans that is unparalleled. So as an example, um, we will have a concentration of human milk oligosaccharides, um, in humans that will be 100 to in some case a thousand times more than what is found in cow milk, um, sheep milk and and pig milk. So that's an example of the concentration level. And also, there's a tremendous range of these human milk oligosaccharides, more than 200 of them have been discovered. So you can see that that breast milk has some very interesting properties that feed the baby, but also the baby's gut microbes.
Dr Rupy: Yeah, yeah. And I I I come I think this comes down to this question about, what do we know about how commensal gut bacteria affect food allergy response? So when I say commensal, I mean the the the natural microbes that you find in the in baby's gut and how that shapes uh, our our immune um, system.
Dr Vincent Ho: Yeah, so again, an excellent question, Rupy. So we know that the gut itself, um, I think it's important to recognize the gut itself is actually the largest immune system in the body. So about two-thirds of all the immune cells in the body actually lies within the gut. And so a key point to emphasize here, Rupy, is that there has to be this fine balance between tolerance to a foreign antigen, um, and an immune response that's generated in the gut. So bacteria play a really key role in initiating that balance. Now, we know that it's that resident or commensal bacteria, as you've said, that plays a very vital role in priming the immune system and helping it to mature. So we know that um, if you don't have immune tolerance, then the immune cells of the gut will just wipe out all of the commensal bacteria. Um, and there'll be no resident gut bacteria at all. So we know that we need to have these commensal bacteria, they're essential here, um, for good immune health. And we know that because of the research in germ-free animals. So these animals are actually bred in a germ-free environment. Um, they're actually extracted from cesarean sections and they grow in a chamber free of all bacteria. Um, so their gut is basically completely sterile. And what we know about um, these germ-free um, mice and and there's been a lot of work done on germ-free mice in particular, is that they have an underdeveloped immune system and they're much more susceptible to getting infections. So, I mean, as an example, um, we know that germ-free mice, um, they can get sick from just 10 salmonella cells in the gut, whilst conventional mice can withstand a million salmonella cells in the gut before becoming unwell. So it just shows you how important it is to have gut microbes.
Dr Rupy: Yeah, yeah, absolutely. And so I I don't want to again, I want to side step this this train of thought that we have here right now because I just want to zoom in on peanut specifically because I I was quite surprised to hear about the rise of peanut allergy specifically in Asia where peanuts appears to be pretty ubiquitous in the cuisine out there. What what do we know about why that's happening? Is it something again, something to do with the uh, reduction in the diversity of our microbial population as a result of Westernized food or there are other sort of, I mean, sure there are other elements at play, but what what is your opinion on that? I was really interested to hear about that specific bit.
Dr Vincent Ho: Yeah, so this is becoming a huge issue as you've said in Asia. So, um, there's been some research work done specifically in Singapore. Um, Singapore, um, has has looked at um, childhood allergies. And back in the 90s, um, we know that peanut allergy wasn't even on the radar, um, in Singapore. And then you move, you know, um, a decade and a half later and it's become a huge issue. So what is it that's increasing the risk of peanut allergy? Um, as you've said, I think that there is a combination of environmental forces at work. Um, I think that because we're living in a more sanitized environment, we're living in an environment which has more exposure to pollutants, which we talked about earlier, these are risk factors to predispose a child to allergy in general. Um, when it comes to peanut allergy, um, we know that yes, the the uh, incidence of peanut allergy seems to be increasing in those countries in particular that are industrialized. So moving towards a more industrialized um, society does increase the risk of peanuts. It's thought perhaps that's related to more exposure to peanut products in general. So for example, there may be more peanut exposure to peanut oil around, um, even peanut um, allergens that might be present around, um, in many many many products. So we know that that peanut allergens extracts can be found in many different foods. Um, and these days, as you know, Rupy, um, our our food is getting more diverse, which is a good thing, but it means that many foods will contain bits of peanuts. You know, I think there's definitely a trend now towards towards having diets that are um, yeah, more diverse, more tasty, more interesting. And you might find that there can be soups, there can be um, there can be uh, dips, for example, that may contain peanut. Um, so that could be part of the reason as well that we might be seeing more peanut in general with with foods.
Dr Rupy: Yeah, yeah, yeah. I mean it was interesting to go back to our earlier point about peanut uh, exposure early, the LEAP study and the, I think it was LEAP-On, which is a follow-up study on that. Um, that that was a, yeah, a mindset shift for a lot of people.
Dr Vincent Ho: Yeah, absolutely. So the LEAP study was actually, um, published in the United Kingdom. So it was a UK study, published in 2015 in a very prestigious journal. And what it found was that, yes, I mean, if you introduce peanuts early, I mean, early in life, and this is again comes back to, um, the concept that we're talking about here, if you expose babies to peanuts in the first 12 months of life, then that can actually help to reduce their risk of developing peanut allergies by creating this immune tolerance. And this is a fundamental paradigm shift to what was thought many like over a decade earlier. So it was thought that, you know, children that were at risk of peanut allergies should avoid peanuts until they had a more mature immune system. So maybe wait till age three before having it. But this strategy, which was adopted by many Western countries, um, just failed to to reduce peanut allergies. And it was actually other countries that uh, where they didn't do this, where children were exposed to peanuts early in life, that they found, yes, there was some protective effect in reducing the risk of of allergies. And so the LEAP study was a great study because it was found that, you know, with a food challenge at the age of five, there were a smaller proportion of children with that peanut allergy compared to those that were avoiding peanuts early in life.
Dr Rupy: Yeah, yeah. I it's amazing just how quickly things can change as well. And like, I've seen it on the in the course of my relatively short clinical career, how we've changed our thinking about these things. And I I want to because we've talked about, you know, the hypotheses around why we see more food allergy, the environmental impacts, maternal diet. And I think now listeners are probably thinking, okay, fine, I understand all this stuff. This is great. And this is where I think your your book has the most uh, practical impact because you've got this nine-week meal plan that's uh, loosely based, I believe on the EAT study, which is all about introducing uh, common allergenic foods in that weaning period to 12 months. Maybe we could talk a bit about the concepts behind why this is uh, useful and also how you've very nicely structured it in the book because I think it's it's and you did it with a registered dietitian as well. So I think it's just a a fantastically practical thing to do, particularly for those who have, you know, worries about allergy as we all do.
Dr Vincent Ho: So, look, I want to give some background to all this and the background behind this diet too. I guess, um, I mentioned before about the PASTEUR study. So the PASTEUR study was that important study, of course, where uh, they wanted to look for associations, um, see what could reduce the risk of um, childhood allergy. And what was interesting in that PASTEUR study was that they looked at diets and um, in in um, a cohort of uh, young infants, what they found was that high, a high diversity of foods was actually protective for allergies in the first year of life, particularly for asthma, um, and food allergies. So it was really good to have a very diverse, um, range of foods. Now, what was very interesting was that they found that the protective effect was particularly strong between six months to 12 months. So this is a really important concept, six months to 12 months. And therefore, if you eat a variety of food types, including allergens between the age of six and 12 months, that is thought to be the key then to protecting against development of later childhood allergies. So with that in mind, it builds us to the EAT study. So building on from the work that was done in LEAP, they found that, yes, if you expose children to peanuts in the first 12 months, that will be that will be a very good thing in terms of reducing allergy risk. But the EAT study was really good because again, this was from the United Kingdom, so great research from from the UK here. But they the researchers wanted to study whether if you introduced um, other allergenic foods in addition to peanuts, so there was peanuts, there's also egg and milk and sesame, um, white fish and wheat. If you introduce those other allergenic foods to infants, was it safe? And it turns out it was very safe. So there was zero anaphylaxis among the more than 1,300 babies that participated in this study. And the challenge, however, is to get parents to get their their babies to really adhere to all of those six foods every week. And this is where um, I've developed a meal plan that should be really helpful to parents. And really this is really to be introduced between that critical window of six months and 12 months. Because as you know, Rupy, um, until six months of age, it's recommended by many societies exclusive breastfeeding until around that time. So there's a lot of um, strong support for for that. But generally, you can introduce solids around anywhere from four to six months. But here we're looking at introducing food allergens around the six-month mark. And the aim here is to introduce these food allergens sequentially for the baby. So sequentially for the baby so that it helps to stimulate their immune system and lead to tolerance. So they're recognizing it, um, but to do it in a way, Rupy, that's actually very safe. So here we're talking about how we can do it in a very safe way so that when you introduce a little bit of allergen to a baby, what are the signs that you've got to look out for? Um, how do you do it? How do you increase the dosage of your allergen to the baby? And once they're once that baby is used to that allergen and is having no issues, how do you incorporate that into their meal meals ongoing? And so that's where the nine-week plan was developed.
Dr Rupy: Yeah, this this makes a lot of sense considering everything that we've uh, talked about thus far. And it's a very pragmatic approach because I think a lot of parents are confused about, you know, the old stuff that they've heard in the past, perhaps stuff that their uh, grandparents have told them as well. And so, you know, having that uh, let's say, that that exposure to use some technical terms, that exposure in a controlled manner for those specific uh, foods that we know have a high likelihood of creating an allergic response on a week by week and also giving them the confidence and the guidance as to look as to what to look out for. I think that's super reassuring and that this is a strategy that we should be really incorporating amongst a number of different uh, areas actually. So those specific allergenic foods, which ones are we talking about here? Which which are the common ones? We've already talked about a couple of them.
Dr Vincent Ho: Yeah, so, look, I think that we've we've talked about those ones in particular. And I guess like in in talking about them, um, I can actually talk about the different types of foods that we're introducing at a particular time point in the in in in the nine weeks. So obviously week one, um, so really around six months of age, we're introducing egg. Egg egg is the first one that's introduced into it. And then around week two, we're introducing dairy. So again, you know, um, you know, from egg to dairy, then week three, sesame. So here we talk about some sesame containing foods that parents can expose their children to. Week four is about fish. Um, then we start getting into the heavier stuff. So week five, we're talking about peanut, okay? And then week six, introducing wheat, week seven is shellfish, week eight is soy, so soy is a big one, and week nine is tree nut. So that shows the sequential order in terms of exposure to these different allergens. And a lot of it's based upon common sense as well in terms of, you know, what are the what are the sorts of allergens that most parents would feed their their children, um, very early on. So we're talking about a sequential order here. And we're making sure that we're not putting in um, similar types of allergens, for example, peanuts and tree nuts too close together.
Dr Rupy: Yeah. Yeah, that that makes a lot of sense because I think, you know, certainly when I work in pediatric emergency and we have, you know, kids coming in, it's very common, obviously, you know, general rash and stuff. Thankfully, we don't see too many anaphylaxis reactions, but certainly a lot of worrying symptoms that uh, die down, especially if we give them a bit of um, medication to to dampen that in terms of antihistamines. But a lot of like in a lot of cases, the the diet's quite mixed already. So you just don't know whether it's the egg or the dairy or whether it's, you know, from the day before and because all these different things have different timelines as well. So it's very, I mean, I can't remember what I had two days ago. So, you know, it's it's it's quite tough, isn't it? So this way it's it's a lot more strategic and we're being a lot more intentional about looking for these issues that we know are so common.
Dr Vincent Ho: Yeah, that's right, Rupy. And it's about also making sure that when you introduce the allergen, you're looking carefully for a reaction. So, I mean, as part of the plan, I recommend introducing an an allergen at a consistent time during the day so that you know, you're looking, you're actually looking for that response. Um, certainly when you when you're introducing new allergens, you've got to be very alert. Um, and hopefully by doing this, I think this could help to reassure parents and um, so that they won't need to be so concerned that they will necessarily park, you know, in front of a hospital emergency when trying out, you know, peanut butter for the first time. At least with this sort of plan, this could hopefully give parents um, some reassurance about a strategy that they can use, um, when starting allergens for the first time for their children.
Dr Rupy: Yeah, absolutely. And um, just on that note, we we talked about probiotics for in the maternal diet. What about probiotics for children specifically? Is there any evidence that we should be uh, including that uh, in in the in the first thousand days?
Dr Vincent Ho: Absolutely. So there was a very um, good study that was published in 2018 from New Zealand. And this looked at the long-term effects of early probiotic use on childhood allergy risk. So in this study here, pregnant women that were assigned um, at 35 weeks gestation to take one of two one of two probiotic strains or a placebo. And these women were asked to continue the capsules until six months after giving birth. And the children were also given the capsules until two years of age. Now, um, as we know that the two-year mark is around, is at the end of the first 1,000 days of life. So these researchers cleverly designed it. So for the first 1,000 days of life, and the researchers followed the children to 11 years of age and they monitored them for the risk of of allergies. So what they found was that if you gave the children these probiotics during early childhood, up to two years of age, it would result in a uh, more than 50% reduction in the risk of eczema and almost 30% reduction in the risk of hay fever, um, over that over that period. So it was huge in terms of of that benefit. And we know that, um, over 11 years because it was done as a long-term study, that exposure to that particular probiotic did reduce the what we call the sensitization to atopy. So that um, the the tendency to have an allergy, it reduced eczema, it reduced wheeze. So it was pretty striking because it tells you that probiotics early in life can make a meaningful difference in the longer term.
Dr Rupy: Yeah, brilliant. Okay, great. So I I I in my head and hopefully the listeners' head, I'm formulating a lovely strategy here. So we've talked about maternal diet, we've talked about the first thousand days in general. And what I'm getting this uh, picture in my head of, okay, diverse diet for the uh, for mother, uh, including lots of different types of foods, including early exposure to some of those allergens, as long as they don't have allergies to those uh, themselves. Uh, I'm I'm thinking about probiotics as well as the potential for for potential use. And then uh, for uh, post-partum, breastfeeding, weaning, including those foods in the sequential manner, potential for probiotics, as well as some other fun stuff, visiting a farm, getting a pet maybe, and removing environmental pollutants. Have I missed anything there? Is there anything else that you've got everything there. That's fantastic.
Dr Rupy: Okay, great. This is great. Okay. Well, I'm I'm glad because I think like people always ask me for tangible information. They want to know, okay, what things we should be looking out for with a little bit of flex as well, so they can have fun with food because I think at the end of the day, I'm a big fan of Yum Cha, for example. When we started talking about Yum Cha, I was just thinking about all the different things I really want to eat. But um, yeah, I I think, you know, this kind of structure is going to be really useful for people. And if we were to future scope for a bit, what do you see on the horizon in terms of treatments uh, and maybe even, you know, preventative measures as well that could be impacting food allergy? Because I mean, make no bones about it, it's definitely on the rise. It's very hard to like uh, flatten that curve at the moment with the current suite of tools that we have. But there must be some things that, particularly as you're involved in the research side of things, that you might be excited about that we might see over the horizon in the next 10 to 15 years, five to 10 years, hopefully.
Dr Vincent Ho: So, um, there's some really interesting things that are being investigated right now. So one of them actually, you might have heard about called vaginal seeding. Um, vaginal seeding is really interesting. And so that's the idea, well, we know that in women that are born, uh, women that have a cesarean section, their children have an increased risk of allergies, notably that of asthma. And so one of the strategies that's been looked at is the idea of vaginal seeding. So that's where newborns that are delivered by C-section are swabbed with their mother's vaginal fluids soon after birth. So they actually get swabbed um, around their skin. Um, and that has been looked at. It's been quite controversial because um, because obviously there are some risks involved in vaginal swabbing. Um, and one of the risks obviously is contracting um, infections. So a baby can contract infections, particularly from group B strep. So it's it's potentially uh, a new strategy that can potentially modulate the baby's gut microbes, um, to be more similar to that of a vaginally um, born infant. Um, but of course, I think that it should be done as part of a controlled trial. So I think it should be done done carefully. Um, it shouldn't be just just done, um, you know, as a sort of a backyard operation. So I think that's that's important. People have looked at immunotherapy and this is actually something which is really relevant to the peanut allergy world. And what immunotherapy is, very simply, it's a type of allergy vaccination where the body's exposed to small amounts of an allergen in gradually increasing doses so that eventually the body can build up immunity to that allergen. And that means that when you get exposed to that allergen in the future, there should be a reduced response to that allergen. In other words, the allergic response or anaphylaxis should be a lot less in response to that. Um, it's been studied a lot in peanuts. This is where it's very controversial because when it comes to peanuts, um, back in the 90s, they looked at injections, immunotherapy in in children and they found that that was actually unsafe. Um, so they switched to oral immunotherapy. And they've actually looked now at um, peanut flour as a type of immunotherapy and it's been certainly in the US, um, there's been a lot of uh, research around it, um, and people talked around it a lot. There are still some risks though, however, um, Rupy, with immunotherapy because a large um, studies, I should say, there's a very large meta-analysis, which is a I I looking at a collection of studies, it actually found that when for peanut immunotherapy, um, there there were certain risks involved with there. I mean, it did increase the risk of allergic and anaphylactic reactions compared with with placebo. So there's some risks there, um, with immunotherapy, but it is an it's a hot area. People are looking at this a lot. Um, another area which is a good one is fecal microbial transplants. So, you know, I mean, could we use, I mean, we we do that with adults, we do that for certain types of conditions like Clostridium difficile infection. Could we do that with babies? Um, certainly fecal microbial transplantation has been studied in young children as early as four months to my knowledge. So really early. Um, and um, there is a study underway at the moment, uh, looking at um, the use of fecal microbial transplantation for peanut allergy. So that's a study which is currently being run through Boston Children's Hospital right now, looking at fecal microbial transplantation. So again, a really interesting area to look at. Um, and finally, um, one really new area is looking at phage therapy. So what is phage therapy? It's a virus that can actually kill off bacteria. And so the aim here, I guess, is could these phages be um, developed to target certain types of more harmful bacteria because what we know from a lot of the research is that certain types of bacteria are linked to allergy, childhood allergy. So and peanut allergy being one of them. So maybe you could develop a virus that can target that bacteria. So really intriguing areas.
Dr Rupy: That's yeah, that's super interesting. We we had um, Professor Karen Naddu on the podcast from Stanford uh, last year, I think, talking about oral immunotherapy, which sounds exciting. Um, but those other areas are uh, yeah, I can totally see those uh, kicking off, particularly if we get over the ick factor of fecal microbial transplants as well. It's not very nice to think about, is it? The crapules and the that kind of stuff. Um, Vincent, this has been brilliant. Uh, I I highly recommend the book. I think uh, it's, you know, such a great resource and it's great to see people like yourself who are working in both academia and clinical frontline medicine as well as a gastroenterologist doing this kind of work and putting the content out in, you know, excuse the pun, digestible formats for people to to to really learn from and and put into practice. So this is great and I really do appreciate you coming on. And hopefully when I'm in Sydney, we can meet up in person for some Yum Cha.
Dr Vincent Ho: That'd be fantastic, Rupy. Thank you so much for having me on the show.
Dr Rupy: Thank you so much for listening to today's podcast episode. Hopefully you get an idea and a picture of what all the information looks like as we discussed in the podcast. It's a maternal diet that has exposure to known allergens as long as the mother does not have issues themselves. Uh, making sure that you're weaning using a systematic approach. There is a potential benefit for having certain supplements in the maternal diet as well as probiotics for children. And there's a whole bunch more information in The Healthy Baby Gut Guide that you can find on the website, thedoctorskitchen.com, on the show notes there, there'll be links there, and you can just Google it as well, Dr Vincent Ho. He's got some great stuff on YouTube. Please do go check it out. And I will see you here next time.
