The human gastrointestinal (GI) system is a complex network of organs and processes responsible for breaking down food and absorbing nutrients. A critical aspect of the functioning of the GI system is the presence of trace gases in the gut, which can significantly impact the digestive system’s health and functioning.
According to ACG Clinical Guidelines on Small Intestinal Bacterial Overgrowth (SIBO) and the North American Consensus on Breath Testing, the three validated and revalidated trace gases that can affect the GI system are hydrogen, methane, and carbon dioxide (CO2). These gases, produced by gut bacteria, can cause bloating, gas, discomfort, constipation, diarrhea, and symptoms shared with other functional GI disorders (FGIDs).
A Breakdown of the Three Validated Trace Gases: Hydrogen, Methane, and Carbon Dioxide
| Trace Gas | Description | Associated Symptoms | Current Diagnosis Options |
| Hydrogen | Produced by gut bacteria, it can affect the functioning of the digestive system by causing excessive gas production leading to abdominal pain and discomfort. High levels are associated with diarrhea. | Diarrhea, abdominal pain, discomfort | Breath test, gastrointestinal endoscopy, stool analysis |
| Methane | Produced by gut bacteria, it can affect the functioning of the digestive system by causing excessive gas production leading to abdominal pain and discomfort. High levels are associated with constipation. | Constipation, abdominal pain, discomfort | Breath test, gastrointestinal endoscopy, stool analysis |
| Carbon Dioxide (CO2) | Produced by gut bacteria, it can affect the functioning of the digestive system by causing excessive gas production leading to abdominal pain and discomfort. However, it is vital in maintaining gut health at appropriate levels. | Bloating, gas, discomfort, and in some cases, abdominal pain and distention | Breath test, gastrointestinal endoscopy, stool analysis |
It is important to note that the symptoms listed in the chart are associated with excessive levels of these trace gases and may not necessarily be caused by them. Also, there may be other symptoms that these gases can cause, and it’s always best for patients to consult with a doctor or healthcare professional to determine the best diagnostic and treatment strategy.
Industry research continues to validate non-invasive breath testing as the gold standard for testing for hydrogen and methane related to FGIDs like SIBO, intestinal methanogen overgrowth (IMO), and carbohydrate malabsorption.
Other Trace Gases Being Researched
Researchers continue to investigate other trace gases that could play a role in the pathophysiology of various GI disorders. Additional trace gases like hydrogen sulfide (H2S), nitrogen, and short-chain fatty acids (SCFAs) may also play a role in the pathophysiology of various GI disorders.
The validation and study of these other trace gases is an active area of research, as they have the potential to provide insight into the underlying mechanisms of various GI disorders and inform the development of new diagnostic and therapeutic strategies.
Note: At the time of publication, no diagnostic technology on the market can currently test for H2S at levels of parts per billion (PPB) found in recent studies looking at normal levels of H2S in human subjects.
Summary
Overall, the production and balance of trace gases in the GI system can significantly impact gut health and function. The gut microbiome, diet, and various environmental factors can influence the production and levels of these trace gases, which can contribute to the development or exacerbation of various GI disorders.
