We talk about the gut a lot around here, but what do we mean when we refer to the “gut” and how does it work? Generally speaking, we are referring to the digestive system, which you also may hear called the gastrointestinal tract or GI tract. Although digestion begins as soon as food enters the mouth, most of the digestive process (breaking down of food) occurs in our stomach, while we absorb most of our nutrients in the small intestine. The stomach and small intestine are also the places for the most digestive distress symptoms associated with IBS, so let’s dive in and learn a little more!
The Gut Absorbs Nutrients
After food moves from the mouth, down the esophagus, it enters into the stomach. Here it is broken down by gastric juices (acids and enzymes) and churned by muscle contractions so that it can be more easily absorbed in the intestines during the next step.
The small intestine is the longest part of the gut. If fact, it’s about 30 feet long…that’s a lot of gut to pack into a small space! In the small intestine, food is broken down into its smallest components. In healthy digestion, these small components are then absorbed into the body and used for all the important processes that keep us alive!Poorly digested sugars found in high FODMAP foods are not broken down and/or absorbed well in the small intestine and are left undigested. Gas and bloating can be the result. Fats can also be difficult to digest for many people as well and it’s why we don’t recommend super high fat meals for those of you with IBS. For more information on fat digestion, read our article “Fat and Digestion“.
Once food has passed through the small intestine, it is stored in the large intestine where it is held until being excreted … yes as poo! This is where those undigested FODMAPs become a source of food for colonic bacteria (the bacteria that live in the colon, aka large intestine). As the bacteria feed on these undigested sugars, they ferment, causing uncomfortable digestive symptoms like gas, bloating and distension.
Although it seems those of us with IBS see fermentation in the gut as the cause of uncomfortable symptoms, this process is necessary for good things to happen in our bodies as well. Bacteria that ferment food waste in the large intestine also produce fatty acids and vitamin K that are reabsorbed by the body. The problem is these poorly digested FODMAPs that move through the body causing trouble!
The Gut is Full of Bacteria
Our gut is swimming with millions of different microbes which are tiny, microscopic organisms like bacteria. Until recently, the microbes that live in the human body and what they do were poorly understood. There is currently a growing body of research exploring more about the fascinating bacteria that live in our gut, and the different roles they have to play in determining our health. This area of research is so exciting! I hope that soon we will be able to learn more through this research how to further improve life with IBS.
Listen to this… It is estimated that the human body contains as many as 100 trillion microbial cells! Yes, I said trillion my friend. All of these different microbes form colonies collectively known as the microbiota (their genes are known as the microbiome).
The human gut microbiota begins developing at birth and continues over the first 3 years of life. A few things starting at birth can have an affect on the composition of the gut microbiota, such as method of delivery at birth and whether a baby is breast fed or formula fed. Breast milk contains many different bacteria from the mother that are beneficial to the baby, including the probiotics bifidobacteria and lactobacilli.
The Gut Microbiota Affects IBS
Along with their role in harvesting nutrients from our food and fermenting those pesky non-digestible carbohydrates (FODMAPS), gut microbes have already been connected to our immune system function. The health of the gut microbiota can be affected by many factors such as the use of antibiotics. The function of antibiotics is to kill bacteria… but because they don’t know the difference between the good and bad bacteria, they kill ALL kinds of bacteria which can affect the microbiota.
The disruption of the normal gut microbiota has been linked to the development of obesity, diabetes, Irritable Bowel Syndrome, autoimmune conditions like Rheumatoid Arthritis and allergies, as well as forms of Inflammatory Bowel Disease such as Crohn’s Disease and Ulcerative Colitis. This research is still in the development phase, so we don’t have loads of information on what we can do to prevent this connection.
Environment can also play a role in determining your gut microbiota, for example, close contact between people and their pets can make it easy to exchange different microbes that might alter the gut microbiota, but is it unknown whether these changes have a positive or negative affect on our health.
So next time you’re stuck worrying about the creepy crawly bacteria that might be lurking nearby, remember that bacteria are all around us (and inside us), both the good and bad. Gut health is all about how our bodies find a balance between protecting us against harmful bacteria and acting as hosts for the good bacteria that help us digest our food and strengthen our immune systems.
Be sure to check back with us next week for a post all about what current research is saying about the gut microbiota, probiotics, and the IBS connection.
Much love & good eating,
Stephanie and the Team