How Your Gut Produces and Uses Hydrogen Gas from Food

This study found that the amount of hydrogen gas produced in our intestines varies with different foods, and a significant portion is either breathed out or consumed by certain gut bacteria.

About 58% of hydrogen produced in the colon is exhaled in breath on average, which is higher than previously accepted, and this proportion varies depending on how much total hydrogen is being produced.

Researchers measured how much hydrogen gas is produced when food is fermented in the large intestine, and where that hydrogen goes—whether it's breathed out, passed as gas, or used by bacteria in the gut. They tested 10 healthy people and found that different foods (like lactulose, pectin, and starch) produce different amounts of hydrogen, and that bacteria in the colon consume some of the hydrogen that's produced. They also discovered that more hydrogen is breathed out than scientists previously thought.

This study suggests that breath hydrogen tests—commonly used to diagnose food sensitivities—may underestimate how much hydrogen is actually being produced in the colon, since a significant amount is consumed by gut bacteria rather than exhaled. However, this is a small study in healthy people, so more research is needed to understand what this means for clinical testing and hydrogen water consumption.

Hydrogen is produced during fermentation in the large intestine and may be excreted in breath and flatus or further metabolized by the flora. However, there is little information about total H2 excretion from different substrates or the extent to which it is metabolized in the colon. We have…

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