THE SMELL OF GUT BUGS

People with elevated levels of hydrogen and methane on their breath tend to be more overweight than others, according to a new paper that points the finger at a microorganism which colonizes the digestive tract.
The culprit is M. smithii, and the study offers the latest tantalizing evidence of a connection between obesity and gut bugs. Researchers tested the breath of 792 people and found that those with lots of methane and hydrogen had a higher body mass index and a higher proportion of body fat. The research seems to lend support to the hypothesis that M. smithii, a leading intestinal methane producer absent in some people and elevated in others, enables cohabiting digestive microorganisms to operate more efficiently, boosting calorie availability to the host.

"Methane and Hydrogen Positivity on Breath Test Is Associated with Greater Body Mass Index and Body Fat," Ruchi Mathur, Meridythe Amichai, Kathleen Shari Chua, James Mirocha, Gillian M. Barlow and Mark Pimentel, Journal of Clinical Endocrinology & Metabolism