SIBO stands for small intestine bacterial overgrowth.

Our small intestine is designed to digest our food, to absorb the micronutrients from these foods, and then feed our bodies. There are many mechanisms in our gut protecting us from having too much bacteria in our small intestine. If you have bacteria in the small intestine (small bowel), that bacteria may be fermenting the foods you are eating resulting in symptoms.

Of the protection mechanisms we have in place against SIBO, the number one would be stomach acid which plays a huge role in our health. Stomach acid is extremely acidic and digests our food through this acid content. It also breaks down protein, provides absorption of minerals and vitamins such as B12, folic acid, and transforms iron into a more absorbable form. Low stomach acid, known as hypochlorhydria, is a condition where insufficient amounts of stomach acid is produced in the stomach.

When I perform a gastroscopy, I will biopsy the stomach lining to assess the health of the lining. If I see concerns like atrial fib gastritis or intestinal metaplasia, that tells me that there is a change in the stomach lining and possibly that the acid production is sub-optimal.

One of the main causes of low stomach acid is a bacteria called H. pylori. Low stomach acid affects between 4% and 10% of the population, and as we get older the condition worsens as our stomach acid production goes down. If your stomach acid fails to kill the bacteria or digest your food well, you could be at risk for SIBO.

Low stomach acid is very frequently seen online. you may have read about the burp tests where you drink a sodium bicarbonate solution and monitor how long it takes to burp.

In my opinion we do not test stomach acid enough. Unfortunately, there are not very many scientific studies looking at gastric acidity because we don’t measure gastric acidity that much. Measuring gastric acidity would mean lowering a probe into the stomach, collecting and aspirating the juices and measuring the amount. We should, I believe, try looking at other methods to evaluate this in order to truly correlate how much high stomach acid or low stomach acid exists because there is this ever growing population of information regarding low stomach acid to be found online, and I am not convinced how much that actually correlates to real life.

There is however, some testing that you can do for stomach acid. One of these is known as the Heidelberg test.

Another aspect that can support us in protecting our small intestine from developing SIBO would be intestinal motility, which is influenced by the actual environment inside the bowel. Motility is impacted by certain types of bacteria, medications and the vagus nerve (which is coming from a deep part in the brain). The ileocecal valve is also important as it should be unidirectional from the small bowel into the large bowel. If the ileocecal valve is not working properly, you are going to have a backflow of bacteria from the colon (which can be thought of as your body’s sewer), into the small intestine where we are supposed to be digesting our food.

Immunoglobulins, which are part of the immune system and are part of the intestinal secretions also help protect your small intestine from unwanted bacteria. We secrete immune proteins in our mucus in our intestine to protect us from these bacteria. Our pancreas and biliary secretions create an environment to reduce the amount of bacteria. People who have bile duct disorders and poor bile flow (possibly from liver congestion) also are at risk for developing SIBO.

When patients ask me, “Why do I have SIBO? And why is this happening to me? What’s happened?”, the reality is it is multifactorial:

  • It could be gastric acid secretion. Although I am not sure how much to actually put on that, there are a large number of patients suppressing their acid through proton pump inhibitor therapy.
  • Intestinal motility could be off.
  • Is your ileocecal valve working properly? Is it being affected by the biggest nerve because you’re stressed? Surgeries of the ileocecal valve certainly puts you at risk.
  • Are you low in immunoglobulins? Do you have poor intestinal secretions?
  • What about your pancreas and your bile duct?

There are so many factors at play and these are some of things that we could look at and explore in order to determine how we move forward and try to heal our guts!