The most abundant intestinal gases in the human body are nitrogen and carbon dioxide. They primarily originate from inhaled air that you swallowed, so most of us who suffer from “gas and bloating” are actually air swallowers from talking and breathing.

However, some gases are produced by bacterial fermentation, like hydrogen, methane, and hydrogen sulfide, as well as the afore­mentioned CO2. These have only very recently joined the league of gasotransmitters led by nitric oxide—the first gasotransmitter “discovered” to be not just a vasodilator but also a signaling molecule used by the microbiome to influence a wide array of bodily functions. This breakthrough discovery garnered a Nobel Prize in 1998. Whoever thought that your gas could be worthy of a Nobel Prize?

OK, so you make some gas, you pass an embarrassing fart that smells like rotten eggs (that’s hydrogen sulfide), you play the old Boy Scout trick of lighting it with a BIC lighter (that’s hydro­gen gas; think Hindenburg, highly flammable), or you contribute to greenhouse gases like the cows (that’s methane gas).

No big deal, you might think; that’s just the cost of doing digestion. Except these biome­-generated gases, which it turns out are all constantly sending signals to the cells in your body, are a really big deal.

For example, not only did nitric oxide signaling function get recognized with a Nobel, it actually got an even bigger accolade in 2019, when researchers declared it to be a hitherto unrecognized sophisticated system that “communicates with and controls the host’s DNA like a chemical language instead of single words.” How’s that for impressive?

And methane, which has possibly the worst rap of all gases for its negative effects on climate, is both crucial for proper mitochondrial function and an important modulator of inflammation.