Nearly half of us are natural methane producers. That's because some people’s gut microbiomes include methanogens, microbes that produce methane as a byproduct of digestion. While this doesn’t mean we’re contributing to climate change in the way that cows do, it turns out that these microbes might be beneficially influencing something closer to home: how we digest our food.
A new study from Arizona State University, published in The ISME Journal, found that people with methanogens in their gut may extract more energy from a high-fiber, whole-food diet than people without them.
“That difference has important implications for diet interventions,” said Blake Dirks, lead author and graduate researcher at ASU’s Biodesign Center for Health Through Microbiomes in a press release. “It shows people on the same diet can respond differently. Part of that is due to the composition of their gut microbiome.”
Different Gut Bacteria, Different Digestion
Our gut bacteria play a major role in breaking down the food our bodies can’t digest on their own — especially fiber. These microbes ferment dietary fiber into short-chain fatty acids (SCFAs), which our bodies then absorb and use for energy. During this process, they also produce hydrogen gas, which, if it builds up too much, can stall fermentation.
Methanogens are specialized microbes that "eat" hydrogen and produce methane in the process. By removing excess hydrogen, they allow fermentation to continue more efficiently, which can lead to greater SCFA production and, theoretically, more calories absorbed from fiber-rich food.
In the study, researchers compared two diets: a Western-style diet (WD) made up of processed foods and low in fiber, and a microbiome-enhancer diet (MBD) full of whole foods, resistant starch, and fiber. Both diets had identical macronutrient ratios, but participants absorbed more energy overall from the Western diet. The surprise came with the high-fiber diet: calorie uptake varied significantly depending on whether someone’s gut produced high levels of methane.
Read More: The Gut Microbiome Could Help Our Bodies Fight Cancer
Measuring Methane Emissions
To test this, participants lived for six days inside a special sealed facility at Florida's AdventHealth Translational Research Institute — a “hotel room” equipped with sensors that measured metabolism and methane emissions. The whole-room calorimeter continuously captured methane from breath and, yes, flatulence, allowing researchers to track microbial activity in real time.
Seventeen adults took part in the study, spending time on each of the two diets. In addition to gas measurements, researchers analyzed stool and blood samples to see how many calories were absorbed and how active different gut microbes were. They found that high methane producers absorbed more energy from the high-fiber diet than low producers did.
According to a statement in the news release Rosy Krajmalnik-Brown, senior author of the study and director of the Biodesign Center said, “The human body itself doesn’t make methane, only the microbes do. So we suggested it can be a biomarker that signals efficient microbial production of short-chain fatty acids.”
Rethinking Diets for Different Bodies
While the participants were all relatively healthy, the researchers are curious to see how methanogen activity might impact people with different health conditions.
“One thing that I think would be worthy to look at is how other populations respond to these types of diets — people with obesity, diabetes or other kinds of health states,” Dirks said.
Studies in mice have linked methanogens to increased body weight even when calorie intake was the same. In humans, the connection is murkier. Some research questions the links between methane production to obesity; potentially tying it to leanness or even anorexia.
“This work highlights the importance of the collaboration between clinical-translational scientists and microbial ecologists,” said co-author Karen D. Corbin. Whether or not methanogens turn out to be key players in weight management, one thing is clear: our microbiome may be shaping our health in more ways than we realize.
Read More: It Doesn't Take Long to Reset Your Gut Health with Small Lifestyle Changes
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Expert Review of Gastroenterology & Hepatology: Obesity, diabetes, and the gut microbiome: an updated review
The ISME Journal: Methanogenesis associated with altered microbial production of short-chain fatty acids and human-host metabolizable energy
Michigan Medicine: This Gaseous Culprit Could Be Causing Your Stomach Pain and Constipation
Having worked as a biomedical research assistant in labs across three countries, Jenny excels at translating complex scientific concepts – ranging from medical breakthroughs and pharmacological discoveries to the latest in nutrition – into engaging, accessible content. Her interests extend to topics such as human evolution, psychology, and quirky animal stories. When she’s not immersed in a popular science book, you’ll find her catching waves or cruising around Vancouver Island on her longboard.
