Study Maps Normal Gas Levels in Human Gut Including Hydrogen

Authors
Journal
Digestive Diseases and Sciences
Year
DOI
10.1007/s10620-021-07254-1
Study Type
clinical
Peer Reviewed
Yes
Country
New Zealand
Health Condition
Functional Gastrointestinal Disorders
Body System
Digestive

TL;DR

Scientists looked at what gases are in your stomach and intestines and found that healthy people have pretty similar amounts of five main gases—mostly nitrogen and methane. They also discovered that eating more fiber makes you produce more of certain gases, which could help doctors figure out if something's wrong with your digestion.

Key Finding

Healthy human intestinal gas contains consistent proportions of five main gases: nitrogen (65.1%), methane (14.4%), carbon dioxide (9.9%), hydrogen (2.9%), and oxygen (2.3%), with dietary fiber intake positively correlating with increased production of fermented gases.

Summary

This meta-analysis reviewed 11 studies to determine what gases are normally present in the human colon (large intestine) and how diet affects them. Researchers found that healthy adults' intestinal gas is mostly nitrogen (65%), with smaller amounts of methane (14%), carbon dioxide (10%), hydrogen (3%), and oxygen (2%). They also found that eating more dietary fiber increases the amount of gases produced, especially the fermented gases like hydrogen and methane.

Practical Takeaway

This study establishes baseline measurements of intestinal gases but does not directly test hydrogen water or its effects on the body. While it confirms that hydrogen is naturally present in the colon at low levels (around 3%), the research provides context for understanding digestive function rather than evidence supporting any health benefits of consuming hydrogen water. More targeted studies would be needed to determine whether hydrogen water has any physiological effects.

Abstract

Background: Understanding intestinal gases volume and composition may contribute to diagnosing digestive diseases and the microbiome's status. This meta-analysis aimed to define the composition of human intestinal gases and changes associated with diet. Methods: Studies were identified by systematic research of the MEDLINE(Ovid), Scopus, and Cochrane databases. Studies that measured the concentration of intestinal gases in healthy adult humans were retrieved. The JBI critical appraisal tool was used to evaluate the risk of bias. The primary outcomes analysed were the concentration of the most prevalent colonic gases. Participants were divided into groups according to dietary fibre content. Results: Eleven studies were included. The following gases were identified in similar concentrations across all studies (mean ± standard deviation): nitrogen (65.1 ± 20.89%), oxygen (2.3 ± 0.98%), carbon dioxide (9.9 ± 1.6%), hydrogen (2.9 ± 0.7%), and methane (14.4 ± 3.7%). Differences according to the dietary fibre were observed, with a positive correlation between fibre and volume of gas produced, particularly in fermented gases (carbon dioxide, hydrogen, and methane). Discussion: The meta-analysis has found defined concentrations of the five most common gases present in human colonic gas. Limitations included heterogenic methodologies, a low number of participants, and few recent studies. These findings may be helpful in diagnostic applications where colonic gas volume and composition are crucial factors, including functional disorders, microbiome analyses, and bowel perforation diagnostics.