The Science of Gut Health (& Why It Matters)

                                                            the science of gut health (&why it matters)

When you think about gut health, you might picture uncomfortable symptoms like bloating, gas, and going to the loo too often. But it turns out that your gut health doesn't just affect your digestive system, it also affects your physical health, like your immune system and, uh, your mental health, including how well you can concentrate and focus and your general productivity.

 This means that if we want to live healthier, happier lives, which is what we're all about here on this channel, then it might actually involve getting our guts into better shape. Now, as a doctor, I've learned a lot about the specific diseases and pathologies that can affect the gut. But in medical school, we learn a lot less about nutrition and the basics of how we can look after our gut day to day. So to learn more about this connection between the gut and the body, I interviewed one of the UK's leading experts on gut health.

 Sophie Medlin is a consultant dietitian specializing in gut health, chair of the British Dietetic Association, and a lecturer at King's College London. And, uh, she regularly features on TV here in the UK. So in this video, we're going to be summarizing a bunch of evidence into actionable recommendations for patients.

patients. And I hope that by applying these tips, you'll not only be pooing better, but you'll also be sleeping and focusing better as well. So let's start with the basics. What the hell is the gut? The gut, as you might know, is short for the gastrointestinal tract. And this is the long tube that starts at the mouth and ends at the anus where our poo comes out. And the primary function of the gut is to break down the food that we eat to absorb nutrients and get rid of waste. But it's actually a lot more than that. 

The gut is also home to trillions of microorganisms, collectively known as the gut's microbiome. And this includes all of the bacteria, fungi, and viruses that live in our, uh, digestive tracts. And these chaps help to break down the food that we eat, turning it into the nutrients that our body needs. And how that works is that when we eat various different foods so let's take plant fiber as an example. You eat some fruits and vegetables, they travel the bits of the bit that you can't digest, the bits we can't break down travel through to our colon, where they're fermented by different species of bacteria and yeasts and other types of microorganisms.

And in that fermentation process, they produce some gas and they produce other things, but they really importantly produce some metabolites, some things that interact with our bodies. So what does having a healthy gut actually mean? Basically, it means having a well-balanced and diverse range of microorganisms bacteria, viruses, fungi, and so on in our digestive tract. And so if a healthy gut is basically a healthy and balanced gut microbiome, then the next question is why should we care about this at all? And the most obvious reason why your gut health matters is that it affects digestive disorders. Like, when your gut microbiome is imbalanced, it can lead to digestive problems like bloating and constipation and diarrhea, and irritable bowel syndrome. 

Let's take them to Hagrid. But the story doesn't stop there. And in the last 30 years, scientists have discovered that the effects of our gut health go way beyond our, uh, digestive well-being because our gut has a massive impact on our mental health and on our physical health, on our risk of loads of different diseases and disorders. And actually, the more we look at gut health, the more we realize that it isn't m impacting every part of our body and every system in our body

. And the way scientists know all of this is that there's now a bunch of evidence that the microorganisms in our gut that are used for digesting food interact with other parts of our body. Let's first take a look at how our gut affects our mental health. You might have heard the gut being referred to as the quote, second brain. Or you've probably heard the phrase butterflies in the stomach, which kind of describes the feeling of being nervous. 

And there's actually a good reason for this. So there is a very strong line of communication between your gut and your brain, which we refer to as the gut-brain axis. And the chattiest organ between your brain and your gut is your gut. Your gut is constantly telling your brain all sorts of different things and throwing messages up that it's got to deal with. So how does this gut-brain access work? Well, it turns out that there are three connections between the gut and the brain that create this strong link. First, there is a chemical connection. The gut microbiome produces neurotransmitters like serotonin and dopamine, which are chemicals in our brains that make us happy and help regulate our moods and behavior. And actually, 95% of the body's serotonin, which is the happy hormone, is produced in the gut.

The scientists then change the composition of bacteria in these mice's intestinal tracts and see how their immune system responds. Yes, it is a little mean, but it's the findings from these studies that show a clear link between the gut microbiome and our ability to produce and develop immune cells and antibodies. So by now, we should know what gut health actually is and why it matters. So let's discuss how to actually get a healthier gut. Now, recently, social media has become a hub for all things related to health and nutrition.

 And while there's some helpful information out there, there's also a lot of fake news that can be misleading and potentially even harmful. And this is particularly true when it comes to gut health, where people are often surging for quick fixes and miracle cures. So, with all that, I asked Sophie a bunch of questions about some recent diet and nutrition trends, and she gave some solid advice about what to follow and what not to follow. 

So we're going to be going through five things that we can add, uh, and five things that we can remove from our diet to improve the balance and diversity of bacteria in our gut, which, as we all know by now, is what makes up a healthy gut tip. Number one, aim for 30 different plants per week. And the most important thing for your gut health is that you're eating 30 different plants a week. So trying to eat loads of variety of different types of plants.

 So eating many different types of plant food improves our gut health by encouraging the growth of different species of bacteria that live there, especially the healthy, good bacteria. Now, plants don't just mean green leaves. Plants include all fruits and vegetables. Legumes like peas and lentils and tofu and canned or dried beans, grains like rice and corn and barley and oats and wheat milk made from nuts or grains like oat milk and almond milk and nuts and seeds like cashews and pumpkin seeds and pine nuts.

Now, when I first heard this, I was thinking, like, how on Earth am I going to get 30 different plants into my diet every week? But Sophie's tip is to break this number down into days. So, uh, over seven days a week, that's about four or five different plants a day. And then that actually makes it feel a lot more manageable. For example, for breakfast, you can have a whole grain cereal or oatmeal topped with some seeds and nuts and then some dried fruit on top. 

And then you already have three, four, or five of those plants in there for the whole day. And if you have some fruit as a midmorning snack and just make sure you have some amount of veg with your lunch or your dinner, then you've covered your bases as far as that goes. Tip number two aims for variety of diet rather than consistency of diet so a lot of diet advice aims for consistency, especially if you're trying to lose weight or build muscle. 

It's a lot easier to just eat the same things every day. But if we want to optimize our gut health, what we should do instead is to aim for variety rather than consistency. And this is very much in line with the whole 30 plants per week tip. And if you have this variety in your diet, then that encourages more diversity and variety of the gut microbiome M, which as we've already discussed, is how we get a healthy gut. 

Tip number three aims for 30 grams of fiber every day most people in England eat less than half of what they actually need in terms of fiber every day. So fiber is a type of carbohydrate that we don't break down and instead of being digested and absorbed, it travels to the large intestine, the colon m. And when it's in the large intestine, it acts as a prebiotic. And prebiotic means basically food for the good bacteria in the body. Now, it's pretty hard to tell how much fiber you're getting in your diet unless you're a nutrition pro. 

So here are some tips. So firstly, as a rough guide, aiming for five servings of fruit and veg and having whole grains with two of your three meals per day and including things like seeds and nuts and dried fruits for snacks will get you most of the way there to get all of the fiber that you need. Secondly, you can find ways to swap out foods in your diet for high-fiber alternatives. So for example, whole grain rice is more high fiber than white rice. 

And thirdly, if you really want, you can actually calculate the amount of fiber in your diet and get to this 30 grams. And here are some options of different foods throughout the day that would add up to that 30 grams. Tip number four aims to take a probiotic. Now probiotics are foods or supplements that contain live microorganisms that are intended to maintain or improve the good bacteria in the gut.

Now this point is a little bit controversial because the evidence is not like wholeheartedly in favor of a probiotic. But there have been a bunch of studies showing that they have good effects. So there's some great research on probiotics and both the gut and brain axis. So how when we're stressed we have these gut symptoms and how probiotics can help to control those gut symptoms. So, one in particular, there are 55 healthy volunteers given a probiotic. Another group is given, uh, a placebo so we can measure the difference. 

The ones who have the probiotic have a significant reduction in psychological stress and a significant reduction in cortisol. So these, like, chemical parameters of stress and anxiety that we can measure. So it's not just how people say they're feeling, it's these objective measures. Now, when it comes to taking probiotics, there are a few different options out there. They either come in the form of tablets or in the form of bottles. 

But you've got to be aware of what the manufacturer and expiry date is, because if it's been sitting on the shelf for ages, then it might not be as effective as it was when you first bought it. And actually, conveniently, the company, Heights, has made a smart probiotic, which I take every day, and they are very kindly sponsoring this video. Now, I've been taking Heights, the brain care smart supplement, for over two years. 

And what I love about Heights, the company is that they're very, very evidence-based in what they do. And I like them so much that I've actually become friends with the founder of the company. And I've personally invested in the company because I was a customer. And then I thought, hey, this is actually some really good stuff, therefore I want to invest in the company, too. And a few months ago, they released their smart probiotic, which is live bacteria for your mind and your microbiome.

 And the idea is that you take a capsule every day, and it contains a few different strains of evidence-based bacteria that are sourced from really high-quality labs and anecdotally. I found that taking this myself for the last few months has meant that my poos are much more consistent than they once were. And you look on the Heights website, you'll find, like, a ton of blog posts and scientific papers and stuff summarizing the evidence behind them. And actually, Sophie was the one who helped formulate the Heights smart probiotic. 

So if you want to check this out, you can use the link in the video description, and if you use this code at checkout, then that will give you an extra 15% off the already discounted quarterly subscription. So thank you so much, Heights, for sponsoring this video. And let's move on. And tip number five is to aim for two portions of oily fish per week. Now, oily fish contains long-chain omega three fatty acids, and our gut loves Omega three.

 It helps to promote the population of good bacteria that helps control inflammation in the body. We need two portions of oily fish a week for our brain health. It's really, really important for controlling inflammation in the brain, the structure of your brain. If you don't eat oily fish, it's a bit like taking out 25% of the bricks of your house and replacing them with polystyrene.

25% of your brain wants to be made from oily fish. So salmon, mackerel, and sardines count as oily fish, but unfortunately, tuna and cod, and sea bass do not count as oily fish. And if you're vegetarian, then you can replace the fish with vegetarian sources of omega three. So, for example, flaxseed or flaxseed oil or canola oil or soybean oil, those sorts of things. Or you can just take a supplement for omega three and actually the Heights Brain Care Smart supplement, not this, but actually has omega three in it. So that's nice and easy as well. 

Okay, let's now move on to five things that we should avoid. And to be honest, for most of these things, it's going to be hard to completely eliminate these foods from our diet. So generally, aiming to reduce our intake of them is probably more realistic and more sustainable in the long run. Tip number one cut down on red meat. So if, like me, you're trying to get hench and build some muscle, then you've probably been told that red meat is a great source of protein. 

You might have also heard of people like Jordan Peterson claiming that the carnivore all-meat diet cured him of his various health problems. But this diet seems to have stopped all of that. I don't have psoriasis. All of the patches have gone. My incurable gum disease and I had multiple surgeries to deal with it is completely gone. But if we look at the scientific evidence behind this, it turns out that too much red meat is not, in fact, good for our gut health. 

And the main reason for this is that the metabolites, the breakdown products of generally red meats, those metabolites are associated with a higher risk of cardiovascular disease and other nasty things like cancer. So the World Cancer Research Fund says we should only have three portions of red meat per week, and that's 350 to 500 grams in total. Otherwise we're putting ourselves in total not every day, no 350 to 500 grams total a week.

 Otherwise, we're putting ourselves at higher risk of bowel cancer. Tip number two is to avoid processed food. Now, this is basically anything that comes in a packet, like sausages or bread or crisps, unfortunately. Peace. O. No, thank you. Um, and the reason why processed foods are generally bad is that they contain a lot of additives and preservatives, and these things make the food last longer. But the way they work is that they stop the natural bacteria inside the food from making the food go off.

And so when we eat these preservatives, we also stop the good bacteria from growing in our gut because the preservatives generally inhibit the bacteria. One example of this is emulsifiers, which are actually found in loads of processed foods, including plant milk emulsifiers that are in lots of processed foods and also in lots of foods that have, uh, got a bit of a health halo, like protein shakes and protein products, that kind of stuff. Emulsifiers, we think are disrupting the lining of people's bowels. So when we have too much of those kinds of things, the tight junctions between the cells in your bowel wall we think are being disrupted and opening up a little bit, allowing too much inflammation into the body and causing all kinds of different problems, but also disrupting that really important mucosal layer in the bowel that is the home for our good bacteria.

 Now, obviously, with inflation and the cost of living crisis and generally stuff getting a lot more expensive, a lot of people are relying on cheap, processed foods to get by. And if you're in that position, then obviously meeting your basic food requirements is going to be the first priority before refining the nutritional value of those food sources, which is kind of priority number two. Tip number three avoid artificial sugars. 

Now this one is kind of annoying because before I had the conversation with Sophie and we did all the evidence and stuff for this video, my go-to fizzy drink for everything was a Diet Coke. After all, I thought, hey, it's not normal sugar, which is bad, instead, like artificial sugar, which is good. But unfortunately, artificial sugars are not very good for our gut health. But what we do know is that when we have artificial sweeteners, our body is anticipating having sugar and things change to get ready to have that sugar. 

When it doesn't come, that has an impact. So there's data to suggest that it increases our insulin production, for example, which makes us ultimately a bit hungrier and can have an impact on our general health as well. So, uh, ideally, sweeteners need to go in the no, thank you bucket as well. Tip number four avoid Diet, fads, and Detoxes now, if you're on social media, then you'll know that there's constantly a new diet and detox trend that's supposed to work miracles and make you look like a supermodel or whatever. In fact, on TikTok, there is a thing called gut talk where people share tips for gut health. 

And Sophie generally recommends being very wary of this kind of trend because generally, they're not coming from qualified medical professionals. So if you do something like a juice cleanse, you're actually depriving your body of loads of really, really important nutrients, meaning it's got to work much, much harder. And in that process of your body working much harder, it's releasing more things that we might consider to be toxic, like oxidative stress and that kind of stuff. And another example is actually a gluten-free diet. 

Now, some people in the world are actually intolerant to gluten or have celiac disease, and for those people, adopting a gluten-free diet is super important for their health. But if you don't fall into that 1% of the population with the condition, then there are not that many health benefits to cutting out gluten from your diet. It's a bit of fat. And tip number five, avoid counting the calories. Now, uh, if you're trying to lose weight or get hunched, then the immediate thing that most people do is count their calories.

 But according to Sophie, it turns out it's not very effective when it comes to gut health in particular. And the reason for this is that calories don't really reflect the nutritional value of what you're consuming. For example, medium-sized McDonald's chips contain around 340 calories. And these other meal options contain approximately the same number of calories race. So, for example, this meal of chicken breast and roasted vegetables comes in at about the same calories. 

This turkey sandwich with fruit comes in at about the same calories. And this brown rice bowl with stir-fried veggies and tofu comes in at about the same calories. But clearly, they have very different nutritional values. On top of that, food labels with calorie information are often wrong. So food companies and the people creating these labels are allowed to be up to 20% wrong about their numbers. So if you're using any kind of tracking app to count your calories, then you're probably going to be at least 20% out. And even if the food labels are correct, then the calories that you end up consuming might not actually be the same as what's on the packet. 

So, for example, calories in cooked celery are different from calories in uncooked celery. And for example, nuts have a very high-calorie count if you look at them on the packet. But actually, your body doesn't absorb all of those calories because some of them are lost in the process of digestion. Now, this final tip is one that I'm personally choosing to somewhat ignore. Sorry, Sophie, because I'm actually counting my calories to try and get henge with macros and stuff.

 But I'm keeping in mind that calories are just one part of the story. They are not the whole story. Ultimately, if we could all go away from the calories and start thinking about whether are we physically hungry? That would be the best way to think about things. Anyway, if you enjoyed this and you want to check out the full podcast episode with Sophie where I ask tons more questions and it's packed with even more stuff around gut health and really trying to explain it from a layperson's perspective. Then you can check out this video over here, which is the full episode. And you can also find that on the Deep Dive Podcast, which is available on all podcast streams, and gaming platforms. So thank you so much for watching for reading this text.