A. Simon and T. Villinger, Argos Messtechnik GmbH
17 August 2021

Our previous blog post describes the analysis of exhaled breath using molecular spectroscopy for determining the concertation of volatile organic compounds which serve as biomarkers. Molecular spectroscopy is elegant because it does not use consumables, it is non-invasive and quick, and measurement and analysis can be performed in about a minute.

Among the gases which can serve as biomarker for a specific health condition is hydrogen (H2). Hydrogen is indicative of certain conditions of gastro-intestinal disorders. Hydrogen and methane breath testing is a widely used diagnostic tool, based on the science that these gases are byproducts of saccharide fermentation by gut microorganisms, rather than human metabolism. Glucose, lactose, and fructose are normally absorbed in the small intestine. Increased gas production following their ingestion is associated with malabsorption or premature fermentation due to excessive bacteria in the small intestine. Hydrogen and methane are absorbed from the gastrointestinal tract, exhaled via the lungs and are thus measurable in breath. Increased gas production following ingestion of fructose or lactose is used to detect malabsorption of carbohydrates. Similarly, increases and ratio of methane and hydrogen in expired breath in response to ingestion of non-digestible lactulose, or glucose are used to predict small intestinal bacterial overgrowth (SIBO)*. So the analysis of both, hydrogen as well as methane in exhaled breath is required in order to assess the person’s health condition (e.g. digestive issues related to SBIO, or malabsorption of lactose, fructose etc.).

The idea to use methane as a biomarker requires adding the capability to analyze Hydrogen to the NUTRISHIELD breath analyzer. Unfortunately, hydrogen can’t be analyzed by infrared laser absorption spectroscopy, the technology which is used for analysis for methane and hydrogen cyanide. Hydrogen is a homonuclear diatomic molecule which can’t be detected by infrared radiation. Sensors for the detection of hydrogen are very common in industry; however the concentration ranges of these sensors are in the low percentage because the usual purpose is the detection of an explosive mixture of hydrogen in air which is in the low percentage range.

The concentration of hydrogen in breath is 4 orders of magnitude less (in the ppm range), so more sensitive sensors are needed. These sensors need to be specific to hydrogen but should not respond to changes in temperature and moisture and should not respond to other gases which may be contained in exhaled breath. Raman spectroscopy, another type of molecular spectroscopy with high specificity could have been used. Unfortunately the power of the laser required as well as the amount of hardware needed and its associated cost excluded its use. Finally an electrochemical sensor similar to the type used in alcohol testing devices was selected. Though care has been taken to exclude effects caused by traces of alcohol or similar gases which could be present in breath, it is a good idea to follow a certain oral hygiene protocol when analyzing exhaled breath.

For specific health analysis (which is outside of the scope of NUTRISHIELD) a preparatory diet may be required prior to the breath analysis.

*) Erdrich, S., Tan, E.C.K., Hawrelak, J.A. et al. Hydrogen–methane breath testing results influenced by oral hygiene. Sci Rep 11, 26 (2021). https://doi.org/10.1038/s41598-020-79554-x