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The Microbiome and Digestion_Final

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>> Hi there. In this lecture, we're going to explore specifically how bacteria fit into this whole mix of surviving, and thriving as a human, and how they impact digestion. At first glance, it may seem that the large intestine got the short into the stick when it comes to digestion. Most of the break down of food and absorption of nutrients is already taken care of by the stomach and the small intestine. So what's left for the large intestine other than being a wide tube for waste? As it turns out, the large intestine maybe home to one of the most important and overlooked functions. It houses the majority of your gut bacteria, as well as all the organisms that comprise your microbiome. Very few microbes hang out in your small intestines due to oxygen, antimicrobial peptides, and lower PH levels. Plus, the shorter transit time in the small intestine makes the environment less hospitable to various bacteria. In the large intestine, leftovers from food are basically just hanging out due to slower transit time and there are less antimicrobials, so the bacteria here can start to breakdown or excavate the leftovers for extra fuel. Their favorite food is non-digestible plant fibers called polysaccharides. Bacteria also like to hangout in the colon because it falls over itself creating a lot of surface area for bacteria to attach. Bacteria live in the lumen, the tube itself and they attach to the mucosal lining which also doubles its food source when you don't provide enough veggies for your bacteria to munch on. Okay, so you know what these bacteria like to eat, but what do they do and why do we have them? Your gut bacteria is the largest contributor to your metabolic process. It can regulate inflammation which as we know can lead to chronic disease, and it's essential for the development of your immune system, perhaps determining whether you develop allergies or an autoimmune disorder. They may even be behind your cravings, your mood, and your behaviors. Many practitioners joke when it comes to dietary changes, good luck with compliance. But what if part of your cravings were due to your microbes in your gut? It might be worth taking a look at how we can create microbial changes. Bacteria are everywhere. There are more bacteria in our gut than humans on the planet. In stool, it's 60% bacteria. The bacteria in your gut help you digest food, create vitamins, and modulate other functions in the body. Drugs and food are metabolized by gut bacteria if they make it down to the colon. The bacteria serve as gatekeepers for things that we want to enter and all that we want to keep out. When you eat a vegetable, your body breaks the carbs down to glucose, but you will have some leftovers which are called indigestible fiber. What's the point of this leftover fiber? It's not just useless mass, it turns out the digestive system is built in a really cool ways so that you can extract the most nutrients possible out of your food. All indigestible fiber is consumed by bacteria who acts like little vacuum cleaners feeding on the fibers you can't digest. And the bacteria in turn, create several molecules that provide nutritional value out of what you might have considered waste. You can imagine how in times when food wasn't so available, this was really important. The body found a way to this neat trick by populating the gut with trillions of bacteria that feed on indigestible fibers. When the bacteria feed on these fibers, they carry out a fermentation process in the gut, the same way sauerkraut or kombucha, or beer is made, except this happens on the inside, 40 to 50% of the energy in a carbohydrate is extracted by fermentation. This fermentation process creates molecules that can also help regulate body functions, such as immunity, hormones, and inflammation. Remember how we have hormones in neurotransmitters that send signals to our bodies to respond in this way or that. Well, the bacteria molecules send signals to our bodies, too. They create some that help us and some that don't, depending on what kind of bacteria they are and what they're eating. Let's go over some of the essential building blocks created by bacteria. Vitamins, like vitamin B12 and K. Vitamin K can only be produced by bacteria. Amino acids, such as, arginine and glutamine, and they can regulate the uptake of amino acids like tryptophan. Short chain fatty acids, these are not just the source of calories, short chain fatty acids play a role in down regulating inflammatory pathogens and even have antitumor properties, and they also help to build intestinal mucosa. Butyrate is an example of a short chain fatty acid which can also be found in foods like butter. This is why butter is included in many gut healing diets. The three main short chain fatty acids created by bacteria are acetate, butyrate, and propionate. Checkout the handout in this module called "Short Chain Fatty Acids" to learn more about these fatty acids. Continuing on, our bacteria create neurotransmitters just like the ones in the brain such as serotonin and GABA. And they also create enzymes that can help break down more food. Bacteria metabolize bile acids and compete for resources with other bacteria, the harmful ones. In doing so, it can starve the other guys out, so it's advantageous to keep the good guys strong. We're learning that the same bacteria species can create different byproducts in metabolites. This leads some to believe that the food we provide they might be more important than the type of bacteria themselves. Again, a supportive facts that what we eat matters. So who are these bacteria? The gut is filled with an entire ecosystem of bacteria. We're only beginning to understand which bacteria do what and since the entire paradigm is switching to looking at the ecosystem and how they operate as a whole, we can't look from the simplistic angle of one bacteria having one function. There are two main categories of bacteria, aerobic and anaerobic. Aerobic bacteria are those that survive with oxygen and anaerobic bacteria are those that survive without. Aerobic bacteria tend to be more often pathogenic meaning they cause disease. The main bacteria in the gut fall into these three categories, firmicutes, bacteroides, proteobacteria, a common group of bacteria in pregnant women. Only, now are we beginning to make connections between diet and the type of bacteria that seem to thrive on any given food source. It does seem that various groups tend to predominate depending on the food source. For example, firmicutes seem to thrive on a high fat diet and dwindle when we fast. And bacteroides love a low-fat diet with tons of fiber. When there is a high ratio of firmicutes to bacteroides, there seems to be a greater risk for obesity. Therefore, we can tell if someone is lean or obese just by looking at their microbiome. Good bacteria or a combination of bacteria in the wrong ratio can play a role in whether we are obese or skinny. In the latest experiments with mice which is how many experiments start, scientists took bacteria from an obese mouse, and placed it in a mouse that was free of bacteria. That mouse became obese, even when they were given the same amount of food and exercise. The reverse also happened. Your gut bacteria can influence how various foods affect your blood sugar. This is why one person eats a banana, it can influence their blood sugar and for another person, there is no effect. The key is in the microbiome. So it's really important for us to understand this community and how it can alter our responses. We're discovering that dysbiosis which just means an imbalance of your microbial community is present in many chronic conditions from Crohn's disease to autism. What we don't know is which is the chicken and which is the egg, but we do know is that the more diverse your bacteria, the healthier and more resistant your ecosystem. Not to be misleading because harmful pathogens will still exist in a gut with a diverse ecosystem. But in a balanced ecosystem, these pathogens seem to exist in small amounts without causing any harm. In the western world, we have about 1,000 to 1,200 different gut species which is a far cry from our ancestors. Why does diversity matter? Imagine that one species gets killed off or dies of starvation, the body or any ecosystem needs an alternative species that can step in and fill that gap. For example, say your client Jill has several types of carbohydrate digesting bacteria taking up residence in her gut, therefore, digestion of carbs is optimal for her. Even if one species gets wiped out, the job can still be completed by the other species. But the less diverse the species becomes, the more resilient the system. So let's say, due to poor diet and lifestyle much of Jill's diversity gets wiped out, including many carb eating bacteria species. She is now going to have a hard time digesting the sandwich she eats for lunch everyday, and she is probably wondering what in the world is going on with her GI tract these days. Chances are on her own, she is not thinking she needs to repopulate her gut bacteria. Instead, she may follow her sister's lead who has a gluten allergy and take her suggestion to cut out wheat. And she'll probably feel somewhat better because now she's swapped out that daily sandwich for a salad. But it's not easing her discomfort completely and it's not getting to the root of the problem because what Jill really needs is to rebalance her gut bacteria. We'll go into more detail throughout this course about what that looks like. For now, just know that this may include eating more fermented foods, getting out in nature, and cutting down on over-sanitizer, all things that reduce diversity. Over time as her gut heals, Jill will be able to reintroduce foods that used to trigger her. However, if she just avoids her triggers and doesn't repopulate her gut, she may have to keep narrowing her food choices rather than building more diversity. Our diverse gut bacteria easily switches between diets, vegetarian, carnivore, and omnivore which was an important ability during primitive life when people had to eat whatever it was available. This is also why different bacteria can create the same essential byproducts, all created for our survival. When it comes to chronic diseases, the microbiome may have insight to offer. When diversity is low, we're more susceptible to disturbances and diseases. This is troubling because the average person's gut diversity has been dramatically changed or been weeded out due to the western diet, antibiotics, and other reasons we'll cover. But the good news is this is reversible. Another benefit of paying attention to bacteria as a Health Coach is that bacteria change really fast. What we eat alters the demographic in the intestines and therefore, our metabolism end cravings. For instance, vegetarians have more veggie digesting bacteria. Alternately, some folks don't have the bacteria to breakdown carbs efficiently. However, when their diet changes, some of these bacteria seem to pop back up as if they'd already been there waiting. The high fat, high sugar, and reduced fiber typical of the SAD, the Standard American Diet seems to correlate to a decrease in diversity, less diversity maybe a reason for the rise in many chronic conditions. Dietary changes can alter gut bacteria for the short and long-term. Dietary changes may occur rapidly, but it can take years to increase overall diversity and ratios of gut bacteria in the microbiome. Another thing to be mindful of is that gut bacteria may determine whether a drug or supplement will work or how the body responds to it. For example, microbes in the gut can determine which painkillers are toxic to your liver. Companies are already exploring how to utilize this information. For example, the Gates Foundation is studying whether we can address malnutrition with peanut butter containing healthy microbes. It'll be really interesting to watch developments unfold as scientists put their new found knowledge of the microbiome to use. When it comes to food and drug safety, we've forgotten to look at bacteria. For example, emulsifiers, binding agents that are included in many processed foods have proven safe in humans, but we're now realizing they affect gut bacteria. Studies show that emulsifiers in our food can kill species of bacteria in the gut that help build mucus lining. This is very bad news because the mucus lining provides protection against other pathogens. When this is disrupted, our body responds with inflammation. We also know that NSAIDs and proton-pump inhibitors negatively affect the microbiome. So to recap, the bacteria in the gut performs several major functions, they help us extract more nutrients from our food while at the same time producing essential nutrients for us. They also send regulatory chemical signals that control functions, such as, hunger and motility. Lastly, they protect us against pathogens which we'll explore later in more detail. These guys are important to consider with any client as you explore dietary and lifestyle choices that affect digestion, and the changes you see in digestion overtime. The microbiome is often referred to as the Wild West. Scientists and experts are holding back from making definitive claims or promises about it because the more we know, the more it seems we don't know. If any information about the microbiome seems confusing, know that this area is rapidly evolving and changing. In the big picture, it still hasn't been determined whether the microbiome is an expression of disease or a potential cause. However, we are seeing that it does evolve and change with us and reflect our current state. As we suspected years ago, the gut still seems to be the center of health. And in an epidemic of chronic disease, we're also placing it at the center of our hopes. Thank you for exploring this new territory with me. Do you have any lingering questions about the microbiome or the role of bacteria in the digestive process? Bring these questions over to the Facebook group where we'll be able to answer your questions and support you, until next time.

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Duration: 15 minutes and 23 seconds
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Language: English
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Posted by: ninaz on Mar 21, 2018

The Microbiome and Digestion_Final

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