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Dr. Paul Mason – ‘From fibre to the microbiome: low carb gut health’

OK. Thanks for hosting me here again. In this talk, I'll take you on a tour of gut health and the low-carb diet. At the end of it, I hope I managed to convince you of a few things. First, fiber is not necessary for a healthy diet. Secondly, There are some low-carb foods that usually cause bloating and other symptoms. And we can define it, Improve bowel symptoms on a low-carb diet, Finally, I want to clarify that now, simply, There is not enough evidence that changing gut bacteria can lead to weight loss. So let's start with fiber.

This is known as the carbohydrate portion of plant foods. Which we cannot digest And remember that fiber only comes from plant foods. It can be divided into two types: We have soluble fiber and this can be fermented by the bacteria in the colon. And that produces gases and something called short chain fatty acids. And then we have the insoluble fiber Which has greater resistance to being broken down by bacteria in the intestine This is the type that increases stool volume. There are several benefits suggested by eating fiber. This includes preventing bowel cancer, preventing bowel obstruction, Help hemorrhoids, reduce blood sugar level, And definitely, treat constipation.

In fact, it is now a familiar wisdom Fiber is an essential component of a healthy diet. So.. Understandably, many of my patients are concerned about the potential effects of removal Cereals and breads with a higher carbohydrate content from their diet. In the Australian diet, these foods make up 45% of the fiber consumed by the average Australian. And when we take a look at the following government advice, They believe that fiber is the best treatment available for constipation and is not outdone. But this opinion does not bear scientific scrutiny. Now, on a widely agreed allegation you would think there is hard evidence to support it. Except that there is no. I was unable to find a single randomized control trial that explicitly investigated symptoms of constipation. Sure, there are experiments with volume and transfer rate and other things like that.

But when we look at the symptoms of constipation, There is no research there. So, I'd like to offer you the best experience I could have had, This was the case control study. In this study, 63 patients suffering from constipation volunteered, A high-fiber diet and a low-fiber diet were compared to those patients. It also included a fiber-free system that requires a complete stop For all kinds of vegetables, grains, fruits, whole grain baked goods and rice.

This graphic here shows the rates of participants in the study before the study They suffer from the symptoms shown on the right side. So you can see Before the study, everyone had constipation. And they opened their intestines with pressure, and a number of them felt bloated. Bleeding and pain. And when study participants followed a high-fiber diet, We can see that the proportion of symptoms and suffering increased. Especially puffiness. And then we have the low-fiber system, And what you see here is that the people on the low-fiber diet actually showed a modest reduction in symptoms. So, the question is what happened, For those, Of the majority in the study who followed a diet without fiber This is not a mistake. I haven't forgotten to add anything on that side. Now, not a single patient in the fiber-free diet has any symptoms. This is really amazing, These results were statistically significant. so far. It wasn't due to a random chance. Just out of interest, Everyone in the diet group is fiber free, He ended up getting one gut activity per day.

How does this compare with the high fiber group? One bowel activity 6.83 days. Do you still think that fiber is good for constipation? Therefore, to understand why fiber reduces constipation gives such striking results Let's take a look at the diagnostic criteria we use as clinicians to diagnose functional constipation, You will notice that each of these criteria relates to ease of passage of stool Via the anal sphincter, which really makes sense. Now fiber, especially insoluble fiber The type you find in wheat bran was long ago declared to have the ability to increase fecal matter. To make it bigger, But when you think about it logically, Is making something really bigger the solution, When are you trying to pass it through a small hatch? Filling the rectum with stool actually makes it difficult to expel the fecal matter. So using fiber to help with constipation is like adding more cars to fix a traffic jam.

But this is not the only argument. People will say, "Well, it makes the stools wet." Except that it doesn't. It's long been known It is well understood Stool moisture does not change, No matter how much fiber or how much water you consume. Fiber does not moisturize the stool, Although it is not a technically a diagnostic feature, constipation is, Bloating is a known problem Many people realize that it is related to excessive fiber consumption The reason for this is that it is not digested in the small intestine. Remember to define the fibers It cannot be digested So it moves to the large intestine, which has a large number of bacteria, Then these bacteria can ferment the fibers, Especially soluble fiber It produces something called short chain fatty acids, Which is known as one of the things that provide health benefits, But in the meantime, bacteria also produce gases.

Like hydrogen, given that the volume of the entire digestive system is only about one liter It only takes a relatively modest amount of gas production before you start to feel bloated. And it starts getting part of the abdominal pain, And anyone who lived during the 1980s, Is there someone who remembers the bran craze? Perhaps you can attest to that. Well what we have left is: when we look at the best evidence they have available, Fiber makes constipation worse It causes bloating and does nothing at all to moisturize our faeces.

So how does this relate to low-carb diets? Well, there are a lot of low-carb foods that are high in fiber. So even though 45% of the fiber in the average Australian diet comes from bread and grains, Many of the foods that we replace when we follow a low-carb diet are rich in fiber And some of the food we love Like broccoli and almond berries. They are in that group that is rich in fiber And if you understand that when it is metabolized in the colon by bacteria, They can produce gas and bloating, You can understand why if you had a bag full of nuts, You may feel a degree of discomfort there. So, some of you may be looking at this trend: "You know what? I had a big bowl of mashed cauliflower yesterday, and it felt a little funny during the night. " Let's turn our attention to something called a short chain fatty acid. So you will remember That once the fibers have been fermented by bacteria, They produce these fatty acids, It is believed to offer some health benefits.

So these bacteria allow the body to save energy from an unusable source, It is provided in the form of fat, Estimates vary widely. But it's usually about 5% energy We actually get from our diet, when we are eating an average diet, It actually comes from this short chain fatty acid that is made from fiber. These short chain fatty acids are said to nourish the cells that line our colon They are called colonized cells, This is thought to help improve conditions such as inflammatory bowel disease (IBD).

Although it is correct, this is an illustration of some of the cells that line the colon. While these cells can use short chain fatty acids for energy, It just does that After converting to ketones first. If ketones are produced from short chain fatty acids This is useful, It makes no sense then for them to be ketones Present in the circulatory system in the case of nutritional ketosis, Or on the ketogenic diet, it could be beneficial for these cells for their ability to reach them In fact, ketones in your circulation may be more effective Because it can be delivered to every colony cell, And not just the ones they are in direct contact with, This is already being demonstrated in studies comparing enemas Which contain chain fatty acids, And ketones given in the circulation, Given ketones have been shown to be in the circulatory system More effective in treating IBD, Which may mean that short-chain fatty acids are not magic at all.

Even if it is, fiber is not the only source of short-chain fatty acids from gut bacteria. This is a graph and it shows the production of a short chain of fatty acids Between a vegetarian diet, with lots of fiber, and an animal-based diet, with lots of amino acids. Here in red, you can see that production of short chain fatty acids is actually higher in an animal-based diet Compared to a vegetarian diet. So it appears that nothing is uniquely useful From the production of short chain fatty acids from fiber at all. So let's turn our attention to one of the supposed benefits of fiber in the diet. Which enables you to control your blood sugar levels. And when you take it in isolation, it's actually true So this graph compares your blood sugar levels between Diet recommended by the American Diabetes Association, Yes, with all this high blood sugar, The Diabetes Association recommends a diet And under that, eat a diet rich in fiber.

So you can actually see that the diet is rich in fiber It actually reduces insulin spikes to some extent. But the point that needs to be clarified is That if you don't eat all of your carbs in the first place, You won't have to worry about controlling the sugars with fiber And even with fiber, if we convert it into units, the blood sugar level still exceeds 10, In addition, if the diet recommended for diabetics had such blood sugar control as that diet You may have started looking for another job Let's take a look at this graph.

This study was also published in the American Diabetes Association, And above, you can see a sugar control diet that has big spikes in blood sugar level. And below you can see that the height looks much better, And as you know, it's much better than the diet you just saw with extra fiber added to it. Now the diet at the bottom is called the low-sack diet. This means a bioavailable low-glucose diet. I guess he can't use the term "low-carb" in the Diabetes Journal, huh? Now for the final thought about whether fiber is an essential part of a healthy diet, Let's just look at the gut of a herbivore that has a really large ascending colon Where fiber fermentation occurs, and its comparison with a human intestine. So clearly, you can see that our digestive system It is not prepared to metabolize or process fibers the way herbivores do. So , I'd like to now move on to the next section of your presentation, And take a look at something else that can cause stomach problems on a low-carb diet. This is something called FODMAPs. So FODMAPs, which are again carbohydrates, are a group of short chain carbohydrates With some common features.

First, they are poorly absorbed in the intestine Because of that, they go down to the colon where they can Their fermentation by bacteria, which causes the gas again. The same way it happens with soluble fiber Also (problem with this) FODMAPs are: Carbohydrates that attract liquids due to a high level of osmotic activity Which can lead to watery stools, Each of these symptoms is seen in the condition we call irritable bowel syndrome (IBS). And also, (besides) it causes faeces FODMAPs can also cause constipation, another thing seen on IBS, And the way to do it is, when the bacteria metabolize them, They produce methane, and methane gas has already been shown to cause constipation And when people suffering from this Irritable Bowel Syndrome have repeated many different studies, When put on a diet low in these FODMAPs, About three-quarters of them are getting major improvements I would like to illustrate this point through a very interesting study published earlier this year.

There is a condition called non-celiac gluten sensitivity These patients develop gut symptoms when they eat foods containing gluten But when we test them for celiac disease, everything appears normal. Now the thing to understand is that foods containing gluten, It also contains something called fructans. This is one of the FODMAPs. This study was conducted in patients who did not suffer from digestive disorders but were allergic to gluten. And she gave them homemade pieces Some of them contained fructans, others contained gluten, and some did not And what you can see on the right Their symptoms were much worse when they were given fructans compared to gluten. So it appears that diagnosing a gluten sensitivity without celiac is actually an issue with FODMAPs. So how does this relate to a low-carb diet? Because we don't tend to eat a lot of wheat, do we? It is true, but FODMAPs are found in a number of other foods, some of which we find on a low-carb diet.

Unfortunately, this includes broccoli. Again, one of the nutrients we saw was high in fiber. So, if you've ever wondered why you feel bloated Or constipation after mashed cauliflower, You might find the answer. Now let's look at the P in FODMAPs This refers to polyols Which is the artificial sweetener called sugar alcohols. Because it mainly provides zero-calorie sweetness, Polyols are widely used in many low-carb bars and desserts. The problem is that it is poorly absorbed, attracts water, and produces gas It gives you light stools Many people on low-carb diets have experienced diarrhea as a result To eat one of Atkins' many bars. Now I'd like to dwell on what we call the microbiome.

Now this reflects the colonies of bacteria or microbes that are inside the human body. But we'll focus specifically on those in the colon, in the large intestine. It has often been said that we have ten times more bacteria than human cells. This is an exaggeration, when we actually look at science, They outnumber us by 1.3 to 1, but not exactly 10 times. So, we'll focus on the microbes below this arrow here The question I specifically want to ask is Do these bacteria make us obese? Because that's what we've heard a lot lately. Now we have over a thousand different types of bacteria Inside our gut, but 90% of it comes from One of two major groups: (firmicutes phyla) or (bacteroidetes) Phyla firmicutes have actually been linked in a number of studies with obesity. Whereas, bacteroidetes have been linked to weight loss And the chart here shows how when you lose weight, The bacteroidetes increase But the thing to understand about bacteria is that They have very specific conditions for their growth.

Some prefer oxygen, others do not. Some like fiber, some don't, etc. And bacteria, if they love the conditions that give them, If it likes the nutrition it provides, it will multiply. So simply by providing a different source of nutrition, We can alter bacterial colonies in our gut. These changes happen quickly. Within one day It has been documented that you can have significant changes in the bacteria inside your gut. But the big question is: Can we intentionally alter the balance of bacteria to lose weight? The main point here is that phyla bacteroidetes, which are associated with weight loss, It also happens to be associated with high-fat ketogenic diets.

This has been found in studies of children on this type of diet When they were being treated for epilepsy. So it has become the case of the chicken or the egg. Is it a change in the bacterial count? Or is it a change in diet that leads to weight loss? So in 2006, this famous paper that was published that showed the probiotic organisms associated with obesity It can make mice fat. They had some germ-free mice, And they gave these germ-free mice some bacteria from some obese mice And from some skinny mice, And they found, in fact, that the bacteria were from obese mice It made the germ-free mice obese Which is why this graph illustrates Production of short chain fatty acids By comparing the two groups And what you can see is that obesity bacteria increased your energy yield By producing more short-chain fatty acids.

But that doesn't mean you can simply grow bacteria in our colonies to lose weight. First, the bacteria were cultured in germ-free mice. There was no competition from other bacteria. It is very unlikely that if you cultured the bacteria in a gut with an existing colony, It will give you the same results Second, the extra energy is derived from fiber. So if you are on a low-fiber diet, There will be no results And the fact that there are short-chain fatty acids that are then converted into ketones, As we know it is an appetite suppressant And that actually means when we're not on a specific calorie diet When we're not just in a cage with a limited amount of food Our dietary intake becomes important. So the ketones that are produced are short chain fatty acids It likely has an appetite suppressant effect, It is expected that the mice will eat less. Therefore, it is not clear that we can simply alter our gut bacteria to lose weight. It seems even further Changing the diet allows weight loss, This is related to the change in gut bacteria, not the cause.

It is the ancient mystery. Is it causation or is it a relationship? So, as a final illustration that what we eat It affects the gut bacteria and is not always in a good way. Let's take a look at this study Trehalose is a sugar made of two glucose molecules. But it is fairly recent and is present in our food supply. It was only approved for use in Australia in 2003 This was after some Japanese scientists discovered a way to reproduce it in large quantities around the year 2000. And it wasn't very sweet But it is very effective in lowering the freezing point of food. Because of that it is used in a lot of things like ice cream. The problem now is That there is a harmful bacterium called Clostridium difficile very fond of tarthalose sugar. Increased consumption since the first decade of the second millennium is linked With a dangerous condition called pseudomembranous colitis Associated with this article So what we eat changes gut bacteria. In conclusion, I'd like to leave you with three key messages: Fiber is not a necessity for a healthy diet.

Second, even with a low-carb diet, some foods contain high levels of fiber Or FODMAPs that can cause stomach upset, And you must be aware of this; And finally, the whole concept of changing our microbiome for weight loss It is a bridge too far from the current understanding of science. Thank you.

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