The primary “stomach” related symptoms can really depend on the individual and the location of the suspected bacterial overgrowth. For example; SIBO that is higher up in the small intestine (doudenum) may result more in upper digestive dysfunction, such as belching, nausea and heartburn. This is likely do to the bacteria impacting stomach emptying or gas production affecting the Vegus nerve, innervating the diaphragm. Although, it is thought that SIBO further down the intestines can also create similar symptoms by impacting the migratory motor complex of the small intestine and the liver.
SIBO that is more in the middle of the small intestine may result more in “stomach cramping”, bloating or constant stomach pain and distention. The jejunum is essentially in the middle of the small intestine and when motility is effected, the gas produced from bacteria gets trapped, which can slowly diffuse into the intestinal lining after causing a lot of “stomach” upset and distention. Mid-intestinal SIBO would also have some detrimental effects on nutrient uptake and result in many of the systemic effects that bacterial overgrowth can result in.
Some Systemic Symptoms and Signs of SIBO
|Learning Disorders (Autism and ADHD
Parkinson’s Disease and other neurological conditions
|Iron deficiency anemia
Vitamin B12 deficiency
Respiratory symptoms (asthma/COPD)
Steatorrhea (fatty stools)
Worsening or causes of chronic liver disease (cirrhosis)
SIBO that has resulted from chronic constipation or lack of motility of the large or small intestine results in the back up of large intestinal bacteria into the small intestine through the ileocecal value. The ileocecal valve can ideally keep bacteria out of the small intestine, but it is not a complete sphincter and sluggish lower bowels can cause this valve to become week and distended. Once bacteria are able to back up into the ileum of the small intestine not only will people feel the bloating and stomach distention that is so common but they may also experience nausea and flatulence that is relieved by bowel movements, as result of gas making its way through the large intestine.
The systemic effects of the microbiota are infinite. The impact of the bacteria in our digestive systems have been associated with hundreds of health conditions ranging from cancer to diabetes. Most of this stems from the effects that our microbes have on our immune systems, but also our liver, brain, kidneys, pancreas, and heart.