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Small intestinal bacterial overgrowth, better known as SIBO, remains one of the most poorly understood digestive diseases. It refers to excessive bacterial growth in the small intestine and causes multiple issues such as extreme bloating, gas, burping, diarrhea, and constipation.
SIBO is far more common than believed but is hugely under-diagnosed because most doctors are not familiar with it. This means that many people with SIBO are given an incorrect IBS (Irritable Bowel Syndrome) diagnosis.
Signs and Symptoms of SIBO
Although SIBO includes mostly digestive symptoms, anxiety and brain fog are also common. Here are some common signs and symptoms of SIBO:
- Bloating
- Abdominal pain after eating
- Nausea
- Gas (both burps and flatulence)
- Constipation
- Weight loss
- Malabsorption
- Fatigue
- Cramps
- Diarrhea
- Malnutrition
- Loss of appetite
- Anxiety
- Brain fog
Complications of SIBO
The majority of nutrient absorption happens in the small intestine, so we don't want bacteria there. When bacteria get into the small intestine, they interfere with digestion and nutrient absorption. In other words, the bacteria are eating our food. And when bacteria eat, they produce gases like hydrogen and methane. These cause burping, flatulence, and bloating.
It is also common in SIBO for the cell lining of the small intestine to get damaged, leading to the permeability of the intestinal barrier. This condition is known as leaky gut. Leaky gut can not only amplify SIBO symptoms, but it can also give rise to food allergies, autoimmune disease, inflammation, food sensitivities, and lowered immunity.
Why Do We Get SIBO?
The body generally has mechanics in place to prevent SIBO. For example, there is a little valve that periodically lets food from our small intestine into our large intestine. If this value gets stuck open, bacteria from our large intestine can travel back up into the small intestine.
The small intestine is also protected by a variety of fluids—acidic fluids from the stomach, anti-bacterial bile from the liver, and even immunoglobulin in intestinal secretions. However, if any of these systems are compromised, then the risk for SIBO goes up. A variety of environmental factors and individual lifestyle and dietary habits can affect these systems. For example, parasites and food poisoning are leading causes of SIBO.
Might SIBO Be Causing Your Anxiety?
An altered microbiome can be a cause of anxiety or depression. Some research even suggests that specific bacteria, inflammation in the gut, or dysbiosis in the gut can lead to increased anxiety. Studies suggest that probiotics may help, but this is not always the case with SIBO.
Other SIBO diet tricks to helping manage gut-related anxiety include consuming collagen, high fiber foods, and omega-3 fatty acids to improve digestion. So if your anxiety started around the same time as gut issues, your gut issues could be the cause.
References
Clapp, M., Aurora, N., Herrera, L., Bhatia, M., Wilen, E., & Wakefield, S. (2017). Gut microbiota’s effect on mental health: the gut-brain axis. Clinics and practice, 7(4), 131-136.
Pimentel, M., Saad, R. J., Long, M. D., & Rao, S. S. (2020). ACG clinical guideline: small intestinal bacterial overgrowth. American Journal of Gastroenterology, 115(2), 165-178.
Quigley, E. M., Murray, J. A., & Pimentel, M. (2020). AGA clinical practice update on small intestinal bacterial overgrowth: expert review. Gastroenterology, 159(4), 1526-1532.
Leite, G., Morales, W., Weitsman, S., Celly, S., Parodi, G., Mathur, R., ... & Pimentel, M. (2020). The duodenal microbiome is altered in small intestinal bacterial overgrowth. PloS one, 15(7), e0234906.
