Researchers from Cedars-Sinai Medical Center's Division of Endocrinology, Diabetes, and Metabolism and Gastrointestinal (GI) Motility Program have found that people with higher body mass index (BMI) and percent body fat tested positive for methane and hydrogen on a breath test. The study was published in the April 2013 issue of The Journal of Clinical Endocrinology and Metabolism. 

There is growing interest in the potential role of gut flora in the development of obesity. Several animal studies have found a relationship between gut flora and weight gain. Methanobrevibacter smithii (M Smithii) is the most abundant methane-producing organism in the human gastrointestinal tract. Doctors Ruchi Mathur and Mark Pimentel have studied its role in irritable bowel syndrome (IBS) and obesity. Their research has found that increased methane on breath testing is associated with higher levels of M smithii in patients with IBS and that methane-positive obese subjects have greater BMI than methane-negative obese controls.  

This is the first large-scale prospective study involving 792 participants to determine the association between methane and hydrogen on breath test with body mass index and body fat. The researchers found that participants who tested positive for both methane and hydrogen had significantly higher BMI and higher percent body fat compared to those whose breath tests were normal, hydrogen-positive only, or methane-positive only. This may be the result of excessive colonization of M smithii in the GI tract. 

The CTSI provided study design and biostatistics support to the research team.  

Next steps include future studies to understand the mechanism of the relationship between GI flora on human metabolism and the roles of M smithii and methane in obesity. 

Further Reading:

Journal of Clinical Endocrinology and Metabolism: Methane and hydrogen positivity on breath test is associated with greater body mass index and body fat

Image caption: 

Image source: