Further causes of SIBO, beyond the most established theory of post-infectious gastroenteritis, vary significantly. Clinically I have seen hundreds, if not thousands, of cases of dysbiosis and have correlated many associated causes which are supported by research. All of these associated causes have an effect on the “terrain” in the digestive system, which as discussed in my last article is critical in setting up the environment for SIBO.
Before getting into the details, I think a definition of Dysbiosis is important. Dysbiosis simply refers to a microbial imbalance inside the digestive tract, vaginal cavity, upper respiratory tract, mouth or even on the skin. And seeing as we have an estimated 100 trillion bacteria and yeast that make up the microbiome (which includes bacteria in all of these places) dysbiosis can be a big deal when it comes to our health.
With regards to SIBO, dysbiosis is occurring in the small intestine, which is a critical area of our bodies, as it houses most of the immune system and is where the majority of our essential nutrients are absorbed! I’ll talk more about this in a different article.
The psychological associations of SIBO are one area that can not be ignored because of the dramatic affect that our “big” brain (head) has on our “little” brain (gut). The problem is that this discussion can kind of become a “Which came first” argument. None-the-less here are the physiological effects that pyschology causes in guts!
Emotional or physical trauma can set us up for big problems in the digestive system because of the “survival” wiring we have in place from our evolution on this harsh planet. If you think back, even in modern history, we have survived a lot, from plagues to famines to wars. In fact one thing humans seem to do well is survive. The way we do this is through interactions between our brains and our adrenal glands, and on a fundamental level, digestion is just not essential to the survival process. Neither is immune function …. apparently.
Anxiety, depression and other mental health struggles, which all of us have experienced at one time or another, can be more genetically “hardwired” for some people. Just ask you mother or father! When anxiety or depression is acute, especially in early stages, a hallmark sign from the body is elevated cortisol. Elevated cortisol can persist for some time in people with chronic mental health concerns, but this is not always the case. What can persist after elevated cortisol is changes in the fear centre and a part of the rationalization centre of the brain, called the amygdala and hippocampus respectively. Study Study
What happens when the amygdala enlarges from acute and chronic stress, is the fear response will become enhanced and fear is thought to, in part, be associated with increased adrenaline and dopamine. When the hippocampus shrinks our emotional connections to memory, along with connections to higher rationalization areas of the brain (prefrontal cortex) are decreased. Essentially we become scared and irrational, with poor focus, attention and memory, along with poor digestion! This is also know as fight, flight or free but I simply refer to it as “survival mode”.
So what does all this psychobabble have to do with SIBO! Well, specifically, cortisol has been proven to suppress immune function, both our while blood cells and our antibodies, which are supposed to identify and remove infections from our bodies. This can include bacteria in areas of the body where they are not supposed to be, like the small intestine. Cortisol also has been proven to weekend the lining of our intestines (and digestive systems in general) which allows for a greater chance of “leaky gut” and “leaky skin” to occur. Interesting chronic mental health conditions are thought to result in low cortisol over time, which has been associated with functional gastrointestinal disorders as well. Study Study
Leaky gut, which will be discussed further in future blogs, is a phenomenon where the microbiome has a greater chance of invading our bodies with less detection from the immune system setting the stage for greater risk of autoimmune disease and other more serious health conditions. Study
Adrenaline has been shown to decrease blood flow to the intestines which further impairs the absorption of nutrients and impacts the repair mechanisms of the intestinal lining. Adrenaline also reduces a critical part of our immune function called secretory IgA. Immunoglobulin A is essentially secreted from the gut and helps our immune systems identify potential pathogens from normal bacteria. It also helps our immune systems distinguish between potential invading pathogenic proteins (like bacteria and yeast) from regular food proteins. This is what can set the stage for food reactions that frequently occur in SIBO, as well as other conditions like eczema, asthma, allergic rhinitis, acne, rosacea along with other systemic diseases.
From mechanisms, like reduction in gastric motility, smooth muscle contraction, and atrophic gastritis, high stress results in a dramatic reduction is digestive secretions like bile, pancreatic enzymes and most importantly, stomach acid. With out these digestive secretions the environment or “terrain” of the gut changes significantly. Stomach acid, for example, not only breaks down protein in our foods, it also sterilizes our food for us, so bacteria that cause food poisoning (acute gastroenteritis) in the first place should not be able to survive. If this isn’t enough to kill the bacteria in our food, try having a bath in bile! Bile is an extremely harsh “base”, similar to bleach. Essentially both stomach acid and bile should take care of SIBO, if they are being properly secreted! Check out these articles to help outline the effects that our brain has on our digestion and more about digestion in general. Study Study Study
Being a holistically minded functional medicine guy, I help people identify and correlate clients symptoms in an effort to find the root cause of disease. This includes all diseases that occur in the body. But for the reasons mentioned above …. the digestive system and stress are a great place to start looking. To learn more about digestion in general this is a good resource.