SIBO stands for small intestine bacterial overgrowth, basically bacteria growing in the small intestine, where they shouldn't. You should have a healthy community of bacteria in the intestines, but they should be isolated to the large intestine, the colon, farther down the digestive tract. When these bacteria end up in the small intestine all sorts of problems ensue.
Why are there bacteria in the intestines at all?
Well, like we said they should be in the large intestine, where they play an essential role in good health. As long as it is the right type of bacteria, in the right place, they do a lot of good:
Patients with SIBO Often Experience:
Bacteria Digest Your Food Before you Do
When you consume food, especially starchy foods, the bacteria in your small intestine will digest that food. Unfortunately, when bacteria break down food they generate gas. That gas builds up in the intestines and results in bloating and pain. That's the same reason that people with lactose intolerance get pain. When they consume lactose and can’t break it down, bacteria do instead. Having SIBO is like being lactose intolerant, and gluten intolerant, and fruit fiber intolerant, and grain intolerant, etc, etc. The bacteria break down all these different foods before you can, and you end up with the gas and bloating.
Bacteria Impact your Intestinal Motility-Causing Diarrhea or Constipation
The gasses that these bacteria produce have impacts on your intestinal peristalsis. Peristalsis is the wave-like movement of the intestinal muscles that carry your food down your digestive tract towards your large intestine. There are different types of bacteria in the intestines, and depending on the type present you may get diarrhea (if they are producing hydrogen, which stimulates persitalsis). Or if you have a different type of organism (technically an Archaea rather than a bacteria) that produce methane, which paralyzes the intestinal wall and results in constipation.
The Small Intestine is an Immune System Headquarters
The immune system is extremely concentrated and active at the intestinal margin. As the contents of your meals are pass by, your immune cells are busily sampling and watching, trying to get the jump on any invaders and responding to any infections. With SIBO there is a constant presence of bacteria in the intestines, the immune system stays perpetually activated, and tires out. This results in a steady and constant low level of inflammation which is particularly problematic. Constant inflammation depletes the adrenals, affects hormonal balance, interrupts sleep, circles back and further disrupts digestion, taxes energy, and can disrupt immune function increasing risk of autoimmune conditions.
Bacteria Fragments are Inflammatory
When you get sick you get the usual, tell-tale symptoms of body aches, chills and fever. Those symptoms are your body reacting to highly inflammatory fragments of bacteria called lipopolysaccharides. (LPS for short) These LPS trigger your immune cells telling you that there is an infection present and to get into bed and let your immune cells get the job done. When you have SIBO the bacteria populating your small intestine are constantly reproducing and dying. As they die they break down and the LPS are absorbed into your body. Even though they are dead they still trigger the immune system and cause those same symptoms that come with getting sick. This usually leaves you feeling sore, achy, and tired but without any hope of a nap and some chicken noodle soup helping matters.
Bacteria Produce Compounds called Biogenic Amines
When proteins sit around bacteria break them down. That’s why they go bad. The amino acids (proteins) are broken down by bacteria. Well, when you have bacteria living in your gut they do the same thing with your last meal. Your food is aging as it is moving through your gut. This is obviously not a good thing. This is a little complicated to explain, but it really helps in understanding how some of the symptoms of SIBO come on so stay with me. Specifically, what is happening is the bacteria in your gut convert the amino acids in that protein to other forms of these molecules, forms called biogenic amines. One example of a biogenic amine is histamine. We all know how histamine feels: itchy eyes, swollen throat, sneezing, itchy skin, hives, etc. Histamine is a converted form (or a biogenic amine) of the amino acid histadine. As the amino acids in your food get exposed to the bacteria in your gut, they get converted into these irritating forms. This is a problem for your body. In fact there is a special enzyme in your intestinal wall called diamine oxidase that converts histamine back to histadine as it is absorbed. This enzyme works fine with the amount of histamine normally found in food, but it isn’t able to keep up with the increased histamine created by the bacteria in SIBO. The excess histamine is absorbed un-changed, causing a whole range of symptoms including itching, migraines, irritability, anxiety, and joint pain. Other examples of biogenic amines are tyramine from tyrosine, and trimethylamine from carnitine, and they can all be problematic in a variety of body systems.
SIBO Causes Leaky Gut
The most serious complication of SIBO is that it results in a breakdown of the intestinal lining. This lining is a sophisticated, "smart" membrane that allows the constituents of food through, but keeps out all the things we don’t want, things like chemicals, heavy metals, pesticides, and bacteria. When SIBO is present, bacteria build up at the intestinal wall and the immune system mounts a response against them. Because the SIBO usually can't be cleared without the use of additional supplements or medication, the immune response goes on and on. The prolonged immune response results in a breakdown of the intestinal lining, and permeability, or leaky gut ensues. The integrity of this lining is vital for all sorts of processes in the body, and most importantly, for proper immune regulation. When the gut becomes permeable, the immune system is constantly exposed to things that aren't necessarily invaders needing a reaction, but still cause an activation of the immune system. Among all the things absorbed, there are some proteins in our food that are, structurally, fairly similar to structures in our own body. (for example milk protein and pancreatic cells) The immune system sees these similar structures so much that, in time it begins reacting to tissues in our own bodies as well. This process of autoimmunity is called molecular mimicry, and the role intestinal permeability plays in it has become widely accepted among the world’s leading immunologists.
How Do I Know if I Have SIBO?
Most people are used to laboratory testing being an expensive and inconvenient experience. However, SIBO testing is both easy and affordable. SIBO is tested using a simple ingested solution and a breath test. It takes about an hour to complete and costs around $130. At our office we use the Metabolic Solutions test because it is easy for our patients, affordable, and tests for both hydrogen and methane producing organisms. We typically get results back within one week.
What is the treatment for SIBO?
There are two parts of treatment: Lifestyle and Supplementation. Lifestyle treatment involves dietary changes and lifestyle management (such as stress reduction, and sleep support). Supplements depend on the specific causes for your SIBO, but for the most part we follow the four Rs:
Thanks for reading.
I'm Kieran, clinician and founder at The Parani Clinic. I'm an acupuncturist, herbalist, and functional medicine practitioner for the past 10 years. I have a deep curiosity in health, biology, culture, medicine, history, and a healthy obsession with the pursuit of the perfect state of health.