What methane in your gut says about your diet

Most people don’t give much thought to the gases produced in their gut, but these emissions might say more about your health than you think.

A little-known microbe that lives in the gut and produces methane may help explain why some people seem to get more energy out of the same foods than others.

Not everyone’s gut behaves the same way. In fact, new research from Arizona State University shows that our gut microbes may influence how efficiently we extract energy from the foods we eat.

What’s going on in the gut?

Our gut is home to an entire community of microbes called the microbiome. These microbes help us break down food, especially the fiber that human enzymes can’t digest.

As microbes ferment fiber, they release short-chain fatty acids, which our bodies absorb and use for energy. During this process, they also release hydrogen gas.

However, hydrogen buildup can slow microbial activity. That’s where other microbes come in. Certain microbes, called methanogens, consume the hydrogen and convert it into methane. Methanogens are the only microbes that produce this compound.

Study co-author Rosy Krajmalnik-Brown is the director of the Biodesign Center for Health Through Microbiomes at Arizona State University.

“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,” said Krajmalnik-Brown.

Diets, methane, and energy absorption

To test their ideas, the researchers provided participants with two types of diets. One was a typical Western-style diet full of processed foods and low in fiber.

The other diet was high in fiber and made up of whole foods. Both diets had the same balance of carbohydrates, proteins, and fats.

Participants didn’t just log their meals – they lived inside a special room known as a whole-room calorimeter for six days at a time.

The room was designed to monitor how much energy the body uses and how much gas it emits, including both breath and flatulence. This setup offered much more accurate data than single breath tests.

Study co-author Karen D. Corbin is an associate investigator at the AdventHealth Translational Research Institute, which partnered with ASU for the study.

“This work highlights the importance of the collaboration between clinical-translational scientists and microbial ecologists. The combination of precise measures of energy balance through whole-room calorimetry with ASU’s microbial ecology expertise made key innovations possible,” said Corbin.

How gut gases affect calorie absorption

The results were clear. Everyone absorbed fewer calories on the high-fiber diet than on the processed one. But people whose guts produced more methane absorbed more calories from the fiber-rich meals than those who produced less methane.

Data from blood and stool samples also showed that high methane production was linked to more short-chain fatty acids being produced and absorbed.

This suggests that methanogens help make the digestion process more efficient – at least in terms of energy extraction.

Blake Dirks, lead author of the study, is a PhD student at Arizona State University’s School of Life Sciences.

“That difference has important implications for diet interventions. It shows people on the same diet can respond differently. Part of that is due to the composition of their gut microbiome,” noted Dirks.

A step toward personalized diets

“The participants in our study were relatively healthy. 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,” said Dirks.

Interestingly, participants were not expected to lose weight during the experiment. Still, some did lose a little while on the high-fiber diet. The research team is eager to investigate whether methanogens in the microbiome could influence weight-loss diets too.

“You can see how important it is that the microbiome is personalized,” noted Krajmalnik-Brown.

“Specifically, the diet that we designed so carefully to enhance the microbiome for this experiment had different effects on each person, in part because some people’s microbiomes produced more methane than others.”

Nutrition isn’t one-size-fits-all

This research highlights the complexity of nutrition. It’s not just about what you eat – it’s also about what your body does with it.

For some people, a high-fiber diet might yield more energy than expected, while others might get less. The key could lie in the invisible community of microbes living in the gut – and particularly in the methane-makers.

As scientists continue to explore the links between gut microbiomes and metabolism, this could be the beginning of more personalized dietary guidance that takes methane – and microbes – into account.

The full study was published in the journal The ISME Journal.

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