Nourish your gut: Episode transcript

 

Acknowledgement [00:00:00]

Medibank acknowledges the traditional owners and custodians of the land on which we record this audio file, the Jagera people and the Turrbal people as the Traditional Custodians of Meanjin. We pay our respect to their Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander people listening today.

Dr Chris Robinson [00:00:20]

Did you know your gut is home to trillions of microbes? Yes, there's an entire universe inside you that's key to your gut health and overall health and wellbeing. Get ready to learn all about the gut and what you can do to keep yours happy and healthy. I'm Dr. Chris Robinson, Chief Medical Officer at Medibank, and with me is gastroenterologist, Associate Professor Jake Begun, and dietician, Dr. Abigail Marsh. In this episode, we'll discuss the link between the gut and your overall health and helpful tips that you can try to support your own gut health.

Assoc. Prof. Jake Begun [00:00:54]

That trifecta, sleep, low stress, and exercise I think can really help improve overall health but also gut health.

Dr. Chris Robinson  [00:01:03]

Please note the content in this recorded discussion is general in nature and is not intended to replace individual health professional care. For people who have been diagnosed with a condition of the digestive system or have any other pre-existing medical condition, please seek advice from a healthcare professional before making dietary changes. Abigail, Jake, welcome to today's podcast. Why don't we first start by you both telling me a little bit about yourselves and your background and what attracted you to gut health?

Assoc. Prof. Jake Begun [00:01:31]

Thanks, Chris. Currently, I am the Director of Gastroenterology at the Mater Hospital, where I oversee a busy gastroenterology unit. My own clinical interests are in the causes of inflammation in the gut, especially chronic inflammatory conditions of the gut, and what the drivers of that are. I also have a research laboratory at the University of Queensland where we investigate the interaction between microbes in the gut and the immune system. I think my interest first started back when I was in medical school, and I ended up actually doing a PhD that was looking at the toxins and other products that bacteria produce that can influence the intestine. And I actually did it in a model organism called C. elegans, which is a worm, where we could do genetic analyses of the responses in these critters. Then I went on to do my gastroenterology training, where I did a fellowship in inflammatory bowel disease, looking at the causes of Crohn's disease and ulcerative colitis.

Dr. Chris Robinson [00:02:22]

Fantastic, Jake. And Abigail?

Dr. Abigail Marsh [00:02:24]

My journey in gut health started when I did a student project looking at diet and inflammatory bowel disease, which sparked my interest in gut health. After graduating, I then went on to work as a clinical dietitian at the hospital before starting my PhD in anti-inflammatory diets and inflammatory bowel disease, which included looking at the gut microbiome. Currently, I'm working as a clinical dietitian at Queensland Health, a research development officer, and at Integrated Gut Health.

Dr. Chris Robinson [00:02:51]

Fantastic. Well, it's exciting to have you both here. Let's dive right in. I think we might start with a few of the basics. And I guess the big question is, what is the gut and why is it so important? Jake?

Assoc. Prof. Jake Begun [00:03:00]

Simply put, the gut is that tube that connects your mouth to your anus, and everything in there is the gut. We often divide it into the foregut, which is the oesophagus and the stomach, and the hind-gut would be the small intestine and the large intestine. I think that when people talk about the gut, they're usually talking about the intestine. And so that is the structure that is responsible for digestion of food, absorption of nutrients. But beyond that, we've now learned that it is an incredible organ that influences so many other parts of the body, including metabolism, mental health, and the immune system, which is something, of course, that I have a big interest in.

Dr. Chris Robinson [00:03:35]

Brilliant. Jake, now that we've talked a little bit about what our gut is, let's talk a little bit about the microbiome. Can you tell me a little bit more about that?

Assoc. Prof. Jake Begun [00:03:42]

So the microbiome of the gut consists of all the microorganisms that are in our gut. And it's quite amazing how much there is. So when you think about the human body, perhaps we have 10 to 50 trillion cells in our body, and we have just as many microbial cells in our body as well, one to one. If you think about the amount of microbial biomass in our gut, we have about two kilograms of microbial biomass in our gut, and that changes depending on where you're in the gut. So the highest concentration of microbes is in our colon, our large intestine. In the small intestine, there's a bit less, and then you move all the way up to the stomach, and there's actually very few microbes. So there's diversity depending on what part of the gut you're talking about. The gut represents an incredible amount of diversity, actually. If you look at the human genome, which we've been recently able to map, there's about 30,000 genes in the human genome. If you look at the number of genes that are represented in the microbiome, it's about 300,000. So our total DNA content is actually 90% microbial and 10% human. And so sometimes we talk about, instead of just Homo sapiens, that we're actually a Holobiont, and we take into account all of the content of our microbiome and us when we consider our genetic diversity.

Dr. Chris Robinson [00:04:47]

Jake, so you've told me a little bit about the healthy gut. What does that look like on an everyday basis with a patient when they're seeing you in your clinic?

Assoc. Prof. Jake Begun [00:04:54]

Yeah, Chris, it's interesting because I have some patients that come into me complaining of terrible symptoms that can be disabling. And I can do all the medical tests that I have. I can do a scope and look inside and it looks normal. I can do stool testing and I don't find anything out of the ordinary. I do blood testing. It all looks normal. But that patient, that person in front of me clearly has a gut that's not functioning well. And on the same side, I can have someone who complains of no symptoms whatsoever. And yet when I do my medical tests, it looks terrible. It looks inflamed. It looks horrendous. So I think that our medical knowledge of what makes a healthy gut is limited at this point. And we really need to work on expanding our knowledge and our understanding of what makes that healthy gut that works for that person in front of us. And so I think that's really a challenge that we have in medicine and in science, and that's where we really need to focus our efforts going forward.

Dr. Chris Robinson [00:05:37]

And I think that's such an important concept that can be applied anywhere in medicine. It's not just about looking at the lab test. It's about looking at the person at the end of the bed as well, and making sure you're joining the two together when you make your determinations.

Assoc. Prof. Jake Begun [00:05:47]

100% And I think that's why actually having people who do clinical medicine and science is so important to continue this. I can't even emphasise how much that is important for advancing our understanding of health and disease.

Dr. Chris Robinson [00:06:00]

Jake, you mentioned the concept of diversity of the microbiome. Can you tell me a little bit more about that?

Assoc. Prof. Jake Begun [00:06:05]

Yes, and I think this is a key concept in microbiome research. When microbiome research first started, I think we had a model in our head that it would be just like looking for a bacteria that causes disease. We'd say we have a disease A, and we can find a bacteria that matches to the disease, and there we have an answer. But it turns out, when we've done the research, that that is not the case. Occasionally we can find that kind of link, but more generally we find that there is what we've termed a dysbiosis of the microbiome. This is a hard term to define, and in fact scientists sometimes struggle with exactly what dysbiosis is. But what we've come together with is this idea that diversity is important for health, and that when you have a disease we often see a decrease in bacterial diversity. Bacterial diversity means that you have a range of species that you can detect. For example, if I looked at a stool sample from a healthy person, I might be able to find 300 to 500 different speciesof bacteria. It's like when you go into a forest and you see all different kinds of trees. Compare that to a plantation when you go in and you only see one species of trees and that's the whole forest; that's what we see is associated with disease. So, really having a broad variety of microbes in the gut seems to be associated with health, and in a disease state, we see that that diversity decreases.

Dr. Chris Robinson [00:07:14[

Applying it to the concept of like a forest or a plantation makes a huge amount of sense. You see, growing up on a farm, you would see if you take out multiple species from the ecosystem, weeds would then proliferate. And it sounds like similar things are happening with our microbiome.

Assoc. Prof. Jake Begun [00:07:26]

Yes. And if you, for example, from horticulture, if you look at bananas, for example, where we now only have one species of bananas, now they're very susceptible to getting disease and getting wiped out. And I think that that also means that in the gut, when you don't have that diversity, you lose some of the resilience that you have in a natural system.

Dr. Chris Robinson [00:07:43]

All righty. So now let's talk a little bit more about the gut microbiome. And what are some of the factors that can impact it throughout the life cycle of an individual?

Assoc. Prof. Jake Begun [00:07:50]

There are so many factors, Chris. But let's start off first just like with the life cycle of a person. We begin with birth. So beginning with birth, there is an important vertical transmission of microbiome that happens from mom to baby. And that can be influenced by a lot of things. It can be influenced by the mode of delivery. Then also we see going from breastfeeding to weaning. There's a big increase in diversity within the gut and new species come in to replicate, and we actually get the most diverse gut bacteria in the early childhood period, so sort of that toddler to early grade school kind of age. And then after that it kind of slowly declines over time until you get to adults or even elderly people where we see that now we're getting into the range where it doesn't look like it's a healthy diversity as it kind of narrows in its uh range. We also see effects during those early periods of life of interventions and environmental influences, so for example antibiotics that are taken within the first two years of life and especially within the first six months of life seem to have an impact on the microbiome that can take a long time to recover from and sometimes never recover. We also see that the types of foods that we have can have a big influence on our gut bacteria. So, if you look at someone growing up in sub-Saharan Africa on a traditional diet, they have a microbiome that is used to lots of fibre, very little meat, and that has a particular appearance to it when you sequence it. And compare that to something like the standard American diet, which we sometimes call the SAD diet. That microbiome is less diverse, it has more bacteria that are metabolising sugar and fats, and we often associate that with not as healthy state.

Dr. Chris Robinson [00:09:26]

That's so fascinating. You described the microbiome proliferating as we sort of progress through, I guess, our infancy and into being an adolescent, I guess. Is that because the exposures that an individual is getting in their life is increasing the foods they're eating, the external exposures they're having?

Assoc. Prof. Jake Begun [00:09:43]

I think there are two things that are happening. Certainly the effects of food and the environment are important in terms of how that microbiome first diversifies and then narrows. But we also have during that period of time an education of the immune system. And this co-evolution of the immune system and the microbiome mean that we're together, us and the microbiome are reaching a state we call homeostasis, which means that we have a balance between the pro-inflammatory and anti-inflammatory activities, between our immune system fighting off some bacteria and accepting others, being tolerant to them, and we find this new equilibrium. And over time, those things change, right? Our immune system changes, our diet changes, and also our gut changes over time as well.

Dr. Chris Robinson [00:10:23]

Now, Jake. You mentioned antibiotics previously and how they can be really actually bad for the gut health and for the microbiome. We know that antibiotics, when applied in the right circumstances, can be life-saving. We've heard all the great things that they can do for our health when we need them. Can you help me understand that sort of positioning there?

Assoc. Prof. Jake Begun [00:10:46]

So that's absolutely right, Chris. There are life-threatening infections that can happen that really do require antibiotics, and those have revolutionised medicine, of course, since their discovery by Fleming so long ago. But I do think that antibiotics in general are over-prescribed, and that's a combination of things. It can be, Doctor Who's very rushed has only a few minutes and it's so much easier to write a script for an antibiotic than talk about how we can potentially control sinusitis in other ways, for example. But it can also be driven by consumers or patients who just have been programmed that an antibiotic is what fixes them when they have a cough or they have an upset stomach and they're going in and that's their mission is to get an antibiotic to fix what ails them. So I think we have to spend a little more time, we have to talk about the risks and the benefits of antibiotics before jumping onto the bandwagon. And with respect to what happens in the gut, studies have shown that it can take up to six months to recover from a course of antibiotics to get back to a healthy microbiome that you had before the antibiotic course. And that also goes for the food supply. There's a lot of foods that we see that where antibiotics is put in the feed of some chickens, for example, this is very common in America as a growth promoter, and we see that that antibiotic resistance now is in the population, which is a bad thing, but also those antibiotics can affect our gut microbiome when we're eating meat that's been raised with antibiotics in their feed.

Dr. Chris Robinson [00:12:03]

Now, you touched on the instances where people really do need antibiotics, and we don't want to take away from that. If your health professional recommends that you have antibiotics, you should have them. But is there anything you can do to shorten that six-month window?

Assoc. Prof. Jake Begun [00:12:16]

That's a fantastic follow-up. We used to think, oh, probiotics make the perfect sense for someone who has antibiotics, right? You take an antibiotic, you kill a lot of bacteria in your gut, but then you can get it back with probiotics. But when we did the research, when we did the studies, that's not true. Taking probiotics after an antibiotic course can actually delay the restitution of a normal microbiome. So the best thing you can do after a course of antibiotics is to take prebiotics. It can bring back that microbiota, that healthy gut microbiome quicker.

Dr. Chris Robinson [00:12:42]

Okay, so prebiotics good, probiotics, the evidence isn't there. Really, really interesting. Can we talk a little bit about stress? Because we've talked about the microbiome and mental health and the connections there. But we're hearing a lot that as a society, we're increasingly stressed. We're seeing what's going on in the world. What impact does the stress have specifically on the microbiome?

Assoc. Prof. Jake Begun [00:13:03]

It seems to have quite a deal of impact, actually, when you look at stress levels in the microbiome. But stress itself is actually also a complex concept. So what is stress? I think that if you ask anybody, they'll tell you what stress is. I feel stressed. But what does that look like when you start looking at it? And it can mean a few different things. It can mean increased stress hormones. We often look at cortisol as a marker of stress hormones. And we know that hormones have a big impact on many aspects of health and disease. So, that's one thing. But also, when people get stressed, they eat differently. So, stress eating. And that can also have an effect on your microbiome. They sleep differently. We know that sleep-wake cycles have a big impact on the microbiome and overall health. And they take part in other activities, be it alcohol consumption, smoking, etc., all of these things that can have effects. So stress itself, I think, is very multifactorial. But when we turn it around, we also ask: Can the microbiome cause us stress? Well, I think it probably can, actually. And certainly when people get a flare of inflammation in the gut with inflammatory bowel disease, we see increased stress. When you have an infection, if you have Bali belly, which affects the gut very much, that can lead to stress. And when people are stressed, they say, oh, I have butterflies in my stomach, right? We have a lot of sensation in our guts that are related to stress. And this also has to do with that bidirectional communication between the brain and the gut, which is one of the, like I said, the biggest nerves in the body connects the gut and the brain.

Dr. Chris Robinson [00:14:19]

That's so interesting. So we talked a little about, the things that we can expose our body to and you know stress being one of them, antibiotics being another. What about the natural sort of stages that people progress through, in particular, say menopause and perimenopause? There's increasing focus on the importance of managing that for women. Tell me a little bit about the microbiome and menopause, is there a connection there at all?

Assoc. Prof. Jake Begun [00:14:41]

So we do see that the microbiome looks different in the perimenopause state and in the menopausal state. And again, this is probably somewhat multifactorial. We know that when hormonal levels change, motility in the gut changes. Motility means how fast things are moving through your gut, what those waves of contractions that are pushing food through the gut look like. And so the time that it takes for microbes to travel through the gut changes the microbiome. So that's one thing. The other thing is that As we mentioned before, bacteria are metabolising hormones and producing hormone analogues. So as the oestrogen, testosterone, and progesterone ratios change, those are the main sex hormones that change during menopause, we see that different bacteria respond differently to that and might be able to grow very well in that environment or they diminish. And they're also converting and activating as well as inactivating those hormones. So yes, there is a connection between those two things. It's complex. But I can say without a doubt that it changes during menopause.

Dr. Chris Robinson [00:15:33]

Abigail, now I want to turn to you and I want to talk a little bit bit about the role of diet when it comes to a healthy gut. Now can we really impact the health of our gut just by changing what we eat?

Dr. Abigail Marsh [00:15:43]

Yeah, definitely. So, what we eat can improve our gut health. So, diet plays a major role in shaping the microbes in the gut, affecting their diversity and function, as Jake mentioned. So, plant-based diets-those which are rich in fruits, vegetables, whole grains, nuts, seeds, legumes- all of those things we've been eating for um, forever are high in fibre, promote a healthy microbiome. So, the reason for this is fibre is cemented in the gut and it produces short-chain fatty acids. Short-chain fatty acids help shape the gut microbiome by creating an environment conducive to the growth of beneficial bacteria. These bacteria in turn produce more short-chain fatty acids, creating a positive feedback loop that supports gut health. Short-chain fatty acids, particularly butyrate, which you get from eating oats and rye products, help to maintain the integrity and the function of the gut lining as well. So super important. Conversely, diets high in red meat, processed meats, white products, refined carbohydrates, contain little fibre. So they don't have this effect on the short-chain fatty acid and also can produce pathobionts, which are species not beneficial for gut health.

Dr. Chris Robinson [00:16:55]

Okay, so in a nutshell, if you like, the more diverse the fibres and the healthy foods that we eat, it leads to a more diverse microbiome?

Dr. Abigail Marsh [00:17:03]

That's correct. So the more different plant foods you can get into your diet, the more diverse your gut microbiome is going to be, including things like fermented foods, so your sauerkraut, kimchi, fantastic, Greek yogurt, another food that's fantastic for gut health.

Dr. Chris Robinson [00:17:18]

Yeah, easy. And they're things that I think that you can find anywhere in the supermarket. They're quite tasty, but it's great to know that they're so good for your microbiome.

Dr. Abigail Marsh [00:17:25]

Yeah. And they're affordable too.

Dr. Chris Robinson [00:17:27]

Brilliant. Brilliant. Very important. So I guess like in a nutshell, fibre is our friend when it comes to our gut. And I guess just one more question on fibre, if that's okay. How much fibre should we be eating? Because is it a huge amount? Is it a handful? You know, what's the hot tip?

Dr. Abigail Marsh [00:17:43]

So the dietary guidelines recommend about 30 grams of fibre. So this is in line with the Australian Guide to Healthy Eating. So if you consumed you know, five serves of vegetables, two to three serves of fruit, five serves of whole grains, you'd be getting enough fibre. However, diversity of fibre is super important as well. So you don't just want to have the same two fruits every morning, the same five vegetables, your frozen peas, carrots, corn, and your Wheat-bix for morning and your white bread for lunch. That's not going to do it. It's really important to get a mixture in.

Dr. Chris Robinson [00:18:15]

Interesting. So just like a diverse microbiome is really important, a diverse range of fibres is also really important for the health of the microbiome.

Dr. Abigail Marsh [00:18:23]

Yeah, definitely. And including things like fermented foods have been shown to really benefit the gut microbiome and increase diversity. Research has also shown that growing your own fruit and vegetables can also be really beneficial on your gut microbiome because having that exposure with the soil, obviously washing it before you eat it, but the harvesting of the food is really beneficial as well.

Dr. Chris Robinson [00:18:48]

Yeah. Fascinating. So my grandmother was onto something when she told me I had to eat sauerkraut every day. Fantastic. Okay. So we hear a little bit about the concept of ultra processed foods. We hear a lot about food additives and sweeteners. I remember one of my lecturers at medical school said, if you can't pronounce the ingredient, it's probably not good for you. Let's talk a little bit about these concepts. Are they really as bad as we may think they are?

Dr. Abigail Marsh [00:19:13]

It's tricky. So there's a processed food and a processed food is any food that has been modified. So a whole grain bread can be considered a processed food, a tinned vegetable can be a processed food, so that's not necessarily too bad. The problem with ultra processing is that foods go through many industrial processes. So that's breaking down the foods, which is removing a lot of the fibre, adding those nasty chemicals and E numbers, flavours and preservatives. These foods are designed to be tastier and last longer. So it can be super attractive. So examples of these include soft drinks, packaged snacks, cakes, processed meats. But yeah, your lecturer was onto something. The best way to determine if a food is ultra-processed is to have a read of the ingredient. If there's something there that you don't recognise, chances are it's ultra-processed and best to stay away from.

Dr. Chris Robinson [00:20:05]

It's an easy tip that we can all probably apply to our diets, I think

Assoc. Prof. Jake Begun [00:20:09]

Do you talk about ultra-palatable foods with your patients ever out of curiosity?

Dr. Abigail Marsh [00:20:12]

Not so much ultra-palatable.

Assoc. Prof. Jake Begun [00:20:14]

These are fascinating, these foods. They're the ones that are the rich and the creamy, and the food industry has really evolved towards these things by adding in certain emulsifiers to get to that.

Dr. Abigail Marsh [00:20:24]

And that's a good point because we do know that some of the food additives are worse than others. And your emulsifiers, which keep those things creamy, are shown to be particularly harmful for the gut, as are artificial sweeteners, which are in everything. So going for that diet Coke is not actually the best option.

Dr. Chris Robinson [00:20:42]

Interesting. Interesting. So all these things that make the foods taste and look and feel so much more enjoyable to consume are actually the things that we should be worried about.

Dr. Abigail Marsh [00:20:52]

Yeah, and they tend to be low in fibre as well, so not having that effect on your gut microbiome.

Dr. Chris Robinson [00:20:57]

So back to the fruit and vegetable aisle it is for all of us, I think.

Dr. Abigail Marsh [00:21:00]

Sticking to the outside of the shops is what they recommend when you go through uni because it's the middle aisles where all those processed and packaged foods are.

Dr. Chris Robinson [00:21:10]

Very, very good tip. I like it. I've read recently that you need to consume 30 different plants per week. And we've touched a little bit around the fact that it has to be a diverse range of fibres. Is it really that many that we should be consuming for a healthy gut?

Dr. Abigail Marsh [00:21:27]

It's definitely something I would recommend. And we think it's true at this stage. The exact number for optimal gut health, we don't know. That 30 recommendation comes from the American Gut Project, where they sampled over 10,000 individuals, the majority of them from the US, but also a few from the UK and Australia. And they found that different, the number of plants you consumed, so those who consumed more than 30 plants, had a greater diversity of their gut microbiome than those who consumed less than 10 plants a day. And diversity had a bigger influence on the gut microbiome than different diet types, such as the vegan or the omnivore diet, which you've probably heard of.

Dr. Chris Robinson [00:22:13]

Yeah, excellent. So 30 is a lot. And we're hearing a lot, you know, cost of living crisis, all those types of things, food insecurity. It can be tricky to get that much healthy fruit and veg. What are some tips that people can take? Obviously, sticking to the outside of the supermarket is a fantastic idea, making sure that you can pronounce the ingredients that you're looking at. What other suggestions have I got?

Dr. Abigail Marsh [00:22:35]

So thinking about plant foods, they go beyond just fruit and vegetables. So thinking about whole grains. And whole grains are really not much more expensive than your white products. So if you're having rice, try and choose brown rice. If you're having pasta, try and choose wholemeal pasta. Or if you want to get more diversity, buckwheat pasta. Try and avoid white bread. White bread, very processed, typically contains no fibre. Going for a white bread alternative, and there's many, many available. So spelt bread, rye bread, wholemeal bread, multigrain bread, really, really beneficial. Adding legumes into sauces. So legumes, tinned legumes, fantastic, super cheap. So you can add a tin of lentils to your bolognese. Or if you're having Mexican, add a can of beans to it. And that's actually a lot cheaper than meat. So, meat at the supermarket is a lot more expensive than your tins of legumes. Get creative. Grate a carrot or a zucchini into your cooking. If you're baking, you can be creative that way as well. I'm sure everyone's seen on Instagram or TikTok, you know, you can make brownies out of beans. You can have carrot cake. You can have sweet potato brownies. There are so many creative ways you can add extra fibre into these foods.

Dr. Chris Robinson [00:23:52]

I love that suggestion of adding the beans to the Mexican or the lentils to the bolognese. And I think so many of us are looking for ways to extend the food that we cook to make sure that we're getting enough and that everyone in the family is getting enough food, but also the good things in the food. So there's some brilliant tips. Abigail? Tell me a little bit now about refined sugars and what are you telling your patients around that and what are some of the negative impacts that that can have on the gut?

Dr. Abigail Marsh [00:24:19]

Yeah, that's a good point. So the Australian diet or the sour diet, as we've mentioned before, is so high in sugar that we're adding refined sugar to everything. You know, people are adding sugar to their teas, to their coffees. Our tinned tomatoes have sugar added to it. And the trouble with refined sugar is it causes that glycemic spike really quickly and then the dip. And there's actually some evidence that that adversely affects those microbes in your gut as well.

Dr. Chris Robinson [00:24:47]

So not only does it make you sleepy, it's bad for your gut as well.

Dr. Abigail Marsh [00:24:50]

So it's sleepier. It gives you that post-lunch, you know, that post-lunch crash. It can detrimentally affect your gut health. It's not good for your teeth. And also, if we're getting our energy from sugar, we're not getting our energy from fibre. So it can also lead to weight management problems.

Dr. Chris Robinson [00:25:11]

So, that three o'clock donut in the afternoon, good idea or not a good idea?

Dr. Abigail Marsh [00:25:15]

What about we swap that three o'clock donut for some veggie sticks with hummus?

Dr. Chris Robinson [00:25:19]

That I could probably do. Fantastic. That's very helpful to understand. So I think it's really helpful, Abigail, to understand that there are some tips and tricks to keep your food really, really healthy, make sure we're getting that diversity of fibres, but also do so in an affordable way. We do hear a little bit of kind of good and bad sort of I guess, suggestions or guidance around frozen vegetables. Are they good for you or are they not as good as fresh?

Dr. Abigail Marsh [00:25:45]

Frozen vegetables are just as good as fresh, especially when you consider fresh vegetables that maybe have been sitting in the fridge for two weeks. They lose some of their nutrients, they wilt, and that wilting actually degrades some of the fibre. So it won't have such a beneficial effect on your gut microbiome. But frozen vegetables are snap frozen. So all those nutrients, that fibre is locked in. So they have just as good an effect on the gut microbiome as your fresh alternatives. Also, with your fruits and vegetables, thinking about affordability, buy what's in season as that really influences the cost. So I often recommend to my clients who are struggling maybe to buy affordable options is if you have a local farmer's market, that's a really good place to go. Get what's in season and they have really good deals there. Organic, you often go to those farmer's markets and see organic food. The research shows there's no benefit of organic food in terms of your gut microbiome. It's not going to do any difference.

Dr. Chris Robinson [00:26:57]

That's, I mean, extraordinarily fascinating, right? You've heard it here, frozen food, just as good as fresh and organic. Frozen vegetables and food. Frozen vegetables. I can't have a frozen pizza and say that that's good.

Dr. Abigail Marsh [00:27:09]

Frozen pizza with some pineapple on isn't going to quite cut it.

Dr. Chris Robinson [00:27:13]

Noted. I'll cross that off the list with the donuts. And the organic thing, I think that's really, really fascinating because you do hear the health benefits quoted around organic food quite frequently. And when it comes to the microbiome, it seems that the evidence doesn't quite stack up.

Dr. Abigail Marsh [00:27:26]

No, and they are so much more expensive. And there is a lot of marketing behind them, which is the term organic is actually not a certified term. So it's quite interesting.

Dr. Chris Robinson [00:27:37]

And I love the suggestion around the farmer's market as well. I love going to the local farmer's market. There's less of a range, but there's really great stuff there. And it kind of challenges you. It's like, what can I make with beetroots today or with kale or whatever it may be? And I think it makes you think outside of the square a little bit when it comes to what you're going to cook.

Dr. Abigail Marsh [00:27:52]

And I think AI is going to be super beneficial for that. So I've tried it. You can write the ingredients you've got. So you go to your farmer's market, you buy these foods. What can I cook? Putting in your dietary requirements, and it gives you some really interesting recipes. So that's a little credit. Top tip, as well yeah, I love it!

Dr. Chris Robinson [00:28:08]

Healthier, cheaper, and it's causing us to be a bit more creative, so you can't go wrong there. Now we've talked a little bit about how quick the microbiome can change when you change your diet, and how you know fibre is your friend. I know myself that sometimes when you do you know stack a lot of fibre into your diet though you can get a little bit bloated, a little bit sort of gassy. What's that all about? Should people, if they're feeling a bit gassy or bloated, should they stop or should they persevere for a little while?

Dr. Abigail Marsh [00:28:35]

Yeah, great question. It is really common to notice a bit more gas when you increase your fibre intake, especially certain fibres such as your cabbage. We've all heard of cabbage farts. Cauliflower or legumes. We all know baked beans make you fart. And that is okay as long as, obviously, it's not problematic or impacting your quality of life, but a little bit of gas, it's a good sign. It means your gut microbes are being fed. The reason you get some of that gas is, for example, when you eat legumes, they contain a type of sugar called, it's a bit of a mouthful, oligosaccharides that the human body can't fully digest. So the fermentation of this sugar produces the gas which can cause flatulence, so not not a bad thing and to reduce it takes simple strategies such as rinsing your legumes really well, the tin varieties, cooking them well but yeah Don't worry about a little bit of gas, a little bit of bloating. It's a sign of a well-fed gut microbiome. However, if the bloating is getting in the way of your quality of life, it's impacting your ability to sleep, to function, then I would recommend seeing a gut health dietitian and working with them to gradually increase the fibre in your diet because it's not helpful just to avoid all those foods because that's going to make the problem worse down the track.

Dr. Chris Robinson [00:29:59]

Yeah, that's so helpful to understand. So, you know, don't give up straight away. Persevere. It could get better. Or if it's not, speak to the right professional to make sure you get that extra advice.

Dr. Abigail Marsh [00:30:09]

Your gut takes time to adapt.

Dr. Chris Robinson [00:30:11]

Yeah, and I think that's such a perfect message. Now, I want to talk a little bit about the unhealthy gut because we've talked about what is the gut, what is a healthy gut, and what can contribute to our healthy gut when it comes to our diet. But when it's an unhealthy gut, what are some of the signs or symptoms that people might have noticed, they might have ignored, and when should they be worried?

Assoc. Prof. Jake Begun [00:30:33]

I think I'd like to just start off by saying what goes wrong sometime that makes an unhealthy gut. In my mind, there are a couple of things. One is if the motility of the gut is abnormal. So if it goes too slow or too fast, that generally is associated with an unhealthy gut. The other one is the immune and inflammation in the gut. So normally there's a balance between the bacteria and the immune system that has an anti-inflammatory, pro-inflammatory, we have just the right amount of inflammation. And if it goes either way, the wrong way, then that can make an unhealthy gut. Too much inflammation or not enough immunity can make an unhealthy gut. And the third thing that I think about is the gut barrier. So, the gut makes a lot of mucus and it has a very specialised, tight covering that prevents the bad stuff that might be in your gut from going across the gutting into your bloodstream. That's called barrier function and when we have an impaired barrier function and increased permeability, that's sometimes labeled as a leaky gut; and that can cause a variety of symptoms as those antigens and things that are in the gut that usually stay there come out into the bloodstream and can cause symptoms. Those three aspects are things that I think can lead to an unhealthy gut. How does that present in terms of symptoms? Well, in my practice, the most common symptoms that people come to me about are pains in the gut, bloating, when the bellies poke out from too much gas in the gut or it's too big, and either diarrhoea or constipation, altered gut motility. And when I try to assess those symptoms, I want to know how severe are the symptoms. Sometimes we all have mild symptoms if we eat the wrong food or too much of one thing or too little of another thing. How often is it happening? Is there something that happens every once in a while? And then finally, what impact is that having on your quality of life? Are these very mild symptoms that you can put up with and that's fine, or are they things that are really keeping you home, you're having sick days because of it, or you're not able to do the things that you really want to do, and so when they get to that level severe pain, frequent symptoms, or really impacting on quality of life, then that's when I think you need to see a health professional, dietitian, GP, maybe even a specialist, and try to get to the bottom of what's causing that.

Dr. Chris Robinson [00:32:30]

I think that's a really important take-home. And it's probably safe to say that every one of us at some stage in our life will experience some version of an upset gut. But that doesn't necessarily translate to having an unhealthy microbiome or an unhealthy gut. It's looking at the frequency and the impact on your life that's really important. But I imagine that, you know, if you're worried, speaking to your health professional is a better thing to do sooner rather than later.

Assoc. Prof. Jake Begun [00:32:52]

Absolutely. And I did just want to also highlight just some red flags that we have in our profession. So for example, if you have weight loss that you're not trying to lose weight, but you lose weight, then that's something that usually raises a red flag with your GP or health professional. If you're noticing blood in your stool, that should not be normal in any circumstance and needs to be investigated. There are benign causes of that, but there can also be more serious causes. So those are two red flags that I have in my book.

Dr. Chris Robinson [00:33:14]

Perfect. Really good to remember. I do want to talk specifically about a a particular type of testing. And so it's bowel screening because we do hear a lot about the bowel screening program. We've got the National Bowel Screening Program that many of us know about if anyone in our family is over the age of 50. But we're also hearing a little bit more about the increased prevalence, if you like, of bowel cancer in younger people. Can we touch on that for a moment?

Assoc. Prof. Jake Begun [00:33:40]

Yep. I think I'll speak first about what we're seeing, and then maybe I'd also ask Abigail to comment on some of the dietary drivers that might be this. So what we're seeing is that the incidence of colorectal cancer has been increasing over the past few decades. It's now the second most common cancer diagnosed in Australians. And as you pointed out, Chris, we're seeing more and more colorectal cancers diagnosed in young people. In fact increase in incidence in young people has been something like 50% in patients under the age of 40-increased rates in bowel cancer. So it's really quite striking. The test that you mentioned is the National Bowel Cancer Screening Program, which is given to all people at the age of 50, mailed out to you. And also, if you talk to your GP about it, it is also available down to the age of 45, which is the new recommended age to start bowel cancer screening. This test looks at microscopic traces of blood in the stool. And what we know is that cancers, or even large polyps, which are the precursor lesions to cancer, cause little bits of bleeding in the bowel, and that can be picked up with these ultra-sensitive tests. And we do basically three tests. More than one of them is positive; one or more of them is positive, then you are encouraged to see a gastroenterologist to get that investigated, usually with a colonoscopy. We know that the best improvement in survival that we see with colorectal cancer is early diagnosis, so catching these lesions early is super important. If we catch a polyp before it becomes a cancer, we can remove it and then that risk is gone; and if we catch a cancer early, it usually can be cured with surgery.

Dr. Chris Robinson [00:35:09]

It's early detection, hugely important in this space. I think what you touched on there, that finding these polyps or these cancers in the worst-case scenario early, it can be a really great outcome.

Assoc. Prof. Jake Begun [00:35:22]

Absolutely. But what's actually driving this is a little, well, it's multifactorial probably, but one of the biggest drivers is probably our diet because we see that the increase in cancer risk is happening mostly in the developed world, America, Europe, Australia, for example. Australia is one of the highest rates in the world. And I really think that is the diet that's driving that. I'd love to hear Abigail's opinion on that.

Dr. Chris Robinson [00:35:44]

Abigail, what are we eating that we shouldn't be?

Dr. Abigail Marsh [00:35:45]

Well, I agree with you, Jake. So, the International Agency for Research on Cancer, so a pretty legit organisation, have said that your red meat and processed meats may increase the risk of colorectal, colon, and renal cancer. So that's quite a significant association. And why do we think that is the case? So process meats contain compounds such as N-nitrous. So that's sort of responsible for that processing and the smoking of meats, which is a known carcinogen. Cooking red meat at high temperatures is also carcinogenic because it produces a byproduct called heterosilic aromatic amines. A little bit of a mouthful, and I'm not sure if I pronounced that right.

Dr. Chris Robinson [00:36:31]

We'll go with it. We'll go with it.

Dr. Abigail Marsh [00:36:35]

Yes, limiting your red meat. So my recommendation in practice is limiting your red meat to no more than three serves of meat. And shockingly, what is a serve of red meat? I may ask, what do you think?

Dr. Chris Robinson [00:36:47]

The size of your palm.

Dr. Abigail Marsh [00:36:48]

The size of your palm. It's about 80 to 100 grams. So, in Australia, if you go to the pub and you order a steak, it's going to be 250, 300 grams. So, sorry, that's your red meat intake done in one week. Processed meats, so your bacon, salami, ham, I just say avoid them. So they contain nitrates. There's some evidence that's emerging mainly in your animal models that they can increase the permeability of your gut wall, which can contribute to inflammation. Inflammatory bowel disease. So, I say try and avoid them and see them as a treat food if you do really crave your bacon and eggs in the morning. Have that once a year on your birthday.

Dr. Chris Robinson [00:37:27]

Bad news for those of us who love a charcuterie board. Yeah.

Dr. Abigail Marsh [00:37:31]

So also the cooking methods of your meat. So there's some evidence to show that marinating your red meat can reduce the carcinogenic potential of the food item. Trying not to cook it at high temperatures. So barbecuing is unfortunately not the best method of cooking, which is devastating for the average Australian.

Dr. Chris Robinson [00:37:54]

I think though, like whilst it's probably upsetting for some people to think that, you know, too much red meat is bad, that's probably not new news for anyone really, is it? And knowing that maybe smaller serves of good quality meat is not only going to be better for your gut health, but it's also going to save you money at the checkout. So in a time of cost of living crisis, any tips to save some money is probably always a good thing.

Dr. Abigail Marsh [00:38:15]

That's right. A steak is a lot more expensive than a thing of frozen veg; that's for sure.

Assoc. Prof. Jake Begun [00:38:21]

One other depressing bit of news on the Australian diet front is that the Surgeon General has recently stated that alcohol can also increase the risk of colorectal cancer. So another strike on the board for alcohol, in addition to impacting liver health, it can also increase the risk of colon cancer.

Dr. Chris Robinson [00:38:38]

And look, I think we always hear the concept of anything in moderation. And we're not telling people they can't enjoy their diets, but we should be conscious that what goes in our mouth will really impact our gut health and our health more broadly.

Dr. Abigail Marsh [00:38:50]

And just thinking about those foods from a young age as well. So I think the ham sandwich, it's one of the most common things we find in our kids' lunch boxes. We really should be thinking of something other than ham to give kids for lunch because gut health, like you said, starts at a young age.

Dr. Chris Robinson [00:39:04]

Yeah, I think that's a fantastic tip. Now, I do like to end these podcasts with a little bit of myth-busting because we do hear so much information. We hear a lot of bro science. We hear about the scientists on TikTok, some of which are great, some of which I'm not so sure about their qualifications. I want to throw out a few sort of concepts, and I'd love just to get your ‘are they good or are they bad?' kind of view. Is that all right? Let's start with juice cleansers.

Dr. Abigail Marsh [00:39:32]

I can go on this one? No. So juice cleansers are limited fibre, high in sugar. The two things we spoke about as being suboptimal for gut health.

Assoc. Prof. Jake Begun [00:39:41]

100% agree. I'd rather you had water than juice.

Dr. Abigail Marsh [00:39:44]

Correct.

Dr. Chris Robinson [00:39:44]

Fantastic. Someone did recommend that I went on juice cleanse once. I refused, so I'm glad that you can both back that up.

Dr. Abigail Marsh [00:39:49]

The only thing I've ever added juice is if you're suffering from terrible constipation, a bit of pear juice or prune juice can help things move along.

Dr. Chris Robinson [00:39:55]

I think the thing with juice, and not to dive too deep into it, it's a lot of that fructose-type sugar and there's no fibre in juice, so it's not good. Now, this one's a bit topical at the moment if anyone's been watching certain streaming services, Apple cider vinegar.

Dr. Abigail Marsh [00:40:07]

So apple cider vinegar increases the acidity of the gut; so that can cause reflux, diarrhoea, and teeth damage. So not necessarily the best for gut health. It does contain some probiotics, which can be beneficial for the gut microbiome, but the amount of probiotics in apple cider vinegar is very small. So it's not a significant source of your probiotics. And to my knowledge, there isn't any strong evidence to support the claims that apple cider vinegar improves gut health.

Dr. Chris Robinson [00:40:38]

Excellent, because I've tried it before. It was horrible. It most certainly gave me reflux, so I'm glad to hear about that. Now, bone broth.

Dr. Abigail Marsh [00:40:46]

Bone broth is my pet peeve, and this is mainly from working in oncology back as a clinical dietitian where people would have bone broth as they had Googled that that prevents cancer. And it was really heartbreaking as these patients were often malnourished, and bone broth doesn't contain any protein. It doesn't contain any energy. The benefits of bone broth have been attributed to the compounds like collagen, bone marrow amino acids, which are released from boiled bones. However, there is no evidence that these products benefit your gut health or your joints. Not to my knowledge, Jake.

Assoc. Prof. Jake Begun [00:41:26]

Nope. I don't see any scientific evidence to support bone broth.

Dr. Chris Robinson [00:41:33]

Excellent, because it's also devoid of joy. I've had bone broth as well, and I was like, what is the craze about? It wasn't for me. Now, this is one of my favourite types of food, fermented foods like miso.

Dr. Abigail Marsh [00:41:42]

Fermented foods are fantastic for the gut health. So miso, sauerkraut, kimchi, Greek yogurt, sourdough.

Assoc. Prof. Jake Begun [00:41:50]

Kombucha.

Dr. Abigail Marsh [00:41:51]

Kombucha, if it's made correctly. Kombucha that is kept on the shelf. It's not going to contain the probiotics because if a probiotic can sit on the shelf for about 12 years, no good. Kombucha you get from the markets or you make yourself, fantastic. And, yeah, there is good quality evidence that shows these foods increase the diversity and richness of your gut microbiome.

Dr. Chris Robinson [00:42:12]

Does the same go for sauerkrauts and kimchi? Should you make them then eat them or can they last a little bit longer?

Dr. Abigail Marsh [00:42:18]

So the pickling of them, they can last a lot longer. Okay.

Dr. Chris Robinson [00:42:22]

Good, good. Intermittent fasting?

Assoc. Prof. Jake Begun [00:42:28]

So intermittent fasting is an interesting one, Chris. It's been around for thousands of years, and it does have some interesting properties on the body. We evolved from hunter-gatherers that used to hunt food and have long periods of time where they weren't eating lots of food. And that's actually how our natural rhythms, our gut rhythms work. And so intermittent fasting, interestingly enough, we might have rediscovered it. And it does have some beneficial effects. It decreases inflammatory tone in the gut. It can increase sensitivity to insulin so you don't have these high surges of insulin that are occurring when you eat. And it generally reduces the incidents of hyperglycaemia when you have really high sugar levels in the blood. Intermittent fasting in my book is a plus.

Dr. Abigail Marsh [00:43:03]

I was just going to say most of the research we have is actually done in males. Interesting. 

Assoc. Prof. Jake Begun [00:43:06]

Oh, that's a good point. 

Dr. Abigail Marsh [00:43:12]

So for females, they can still do intermittent fasting, but they just need to do it with a bit more caution and guidance from a health practitioner because intermittent fasting can adversely affect hormones. So not the best for fertility and that sort of thing.

Dr. Chris Robinson [00:43:22]

Really important tip. Absolutely. One last diet to ask about, the keto diet.

Dr. Abigail Marsh [00:43:28]

Yeah, so the keto diet is characteristic of a high-fat, high-protein diet. So that's how it works. So we end up burning our fat stores, not our – glucose stores because we're not having any carbohydrates. So that doesn't produce glucose. However, if we're having no carbohydrate, we're having no fibre. So that is not a great diet for your gut microbiome. However, people do often see really good effects with a keto diet for weight loss. So, you know, some people may do a keto diet for a short amount of time, but it's really something that should not be recommended for the long term. And it does often have other adverse health effects too. Like if you're having a high-fat diet, you've got to be careful of your heart health, your cholesterol levels, all of those sort of things. So it's not something that I would recommend.

Dr. Chris Robinson [00:44:23]

Something to engage with caution by the sound of it, particularly given the conversation we've just had about red meat and the impact that can have on your health. Now, I want to dive into another question around the research in gut health. We've talked about the proliferation of research, if you like, over the last 20 years. What's coming next? What do we see coming down the pipeline from either of you?

Dr. Abigail Marsh [00:44:44]

I can start if you like. So I think we're going to see a lot more in the personalised nutrition space, which being a dietician, I'm super excited about. So we've kind of got that microbiome testing at a level where we can see what species are in the gut. We can see the diversity and we can see the richness. However, the research is not quite there. It's not quite there in terms of what we can specifically recommend to improve. Every single specific species in your garden, what pattern works best for people, it's definitely we have more evidence than we did 12 months ago, um but yeah, I'm really excited to see that body of evidence grow so we can really work on more personalised nutrition, looking at the person's microbiome and being able to recommend exactly what to eat.

Dr. Chris Robinson [00:45:26]

I love that. So it's precision dieting, if you like. Very, very cool. Jake, for you?

Assoc. Prof. Jake Begun [00:45:30]

I see two major advances I think are going to be coming. One is that we're going to be able to tell the difference between different microbes in the gut to greater accuracy. So right now we are often seeing things at the species level or sometimes even just at the genus level. And that would be like saying that, a dog in front of us, be it a schnauzer or a pit bull terrier or a poodle or a doberman are all the same. And that's clearly not true. So what we're talking about now are strains of bacteria. And each one of those strains might have different functions. So just because you have that one species, that might be doing a good thing. But if you had a different strain of that species, it might be doing something very different. So that's important. The second thing is we've been focused very much on who's there. So we're seeing what percentage of bacteria of A you have and what percentage of bacteria B you have. But what I think is more important is what they're doing there. And so we're moving now into the field of microbial products. What compounds are they producing and how is that interacting with your body? And I think that's where it's going to be happening because you can have one bacterial strain that produces a very good effect if it's given the right nutrition, for example, but if you feed it something else, you can have a very different effect. So it's going to be very important to know how those individual bacterial strains are actually producing the things they do to get the effects we see.

Dr. Chris Robinson [00:46:41]

There, we go. You heard it first here. It's all about personalised medicine when it comes to the gut health; I love it! Now a tricky question maybe, but I'm going to ask both of you anyway: If you could recommend one thing to our listeners today that would really help them support their gut health, what would it be?

Dr. Abigail Marsh [00:46:56]

So I think I've mentioned this a lot: aiming for your 30 different plant foods per week. So fruits, veggies, whole grains, nuts, seeds, get them into your diet. What I maybe haven't spoken as much about is your herbs and spices. These are fantastic for your gut health. I do say they only count as half a point for your 30 plant food checklist, but including them in your diet is really beneficial. And there's a little bit of an extra if you can grow them yourself. So if you have a little herb garden or a little fruit and veggie patch, and you don't necessarily need a big garden to do this. If you live in an apartment, I've seen beautiful planters that you can get for the balcony at local hardware stores. So that can be a really good thing to trial. And the exposure with the soil can also help with your gut microbiome. So that would be my little challenge and top tip.

Dr. Chris Robinson [00:47:46]

Jake? 

Assoc. Prof. Jake Begun [00:47:48]

I agree that healthy eating is so important for gut health, and I'll just add on that also healthy lifestyle is really important for good health. So, that includes getting regular exercise, getting good sleep habits, and as we talked about in the beginning, trying to keep your stress levels low. And that trifecta, sleep, low stress, and exercise, I think can really help improve overall health but also gut health.

Dr. Chris Robinson [00:48:09]

Something that could benefit all of us. You've heard it here. We've talked about sleep. We've talked about exercise. We've talked about diversity of the foods we eat. All of these are things that are really important to helping with our gut health. Now, it's been a pleasure to have this conversation today. I've learned so much. I'm most certainly going to diversify the fruit and vegetables that I have in my diet. And I think the people who listen are really going to benefit from it. So thank you both for your time today. It's been really insightful. Thanks for joining us today. We hope you learned more about the gut and what you can do to support your own gut health. Please note, the content in this recorded discussion is general in nature and is not intended to replace individual health professional care. For people who have been diagnosed with a condition of the digestive system or who have any other pre-existing medical condition, please seek advice from a healthcare professional before you make dietary changes. Please note the content in this recorded discussion is general in nature and is not intended to replace individual health professional care. For people who have been diagnosed with a condition of the digestive system or have any other pre-existing medical condition, please seek advice from a healthcare professional before making dietary changes.