Unabashed at digging into leftovers, the less reputable bacteria among the 200 strains in your large-intestine start to chow down. Their population grows as they divide into new generations to take advantage of the bounty. And as they gulp in the big sugars, they let out gas. In essence, your gut accumulates millions of wee bacterial farts. Believe it or not, the bulk of any given toot is unscented.
Gas is composed mainly of unsmellable stuff like hydrogen, nitrogen and carbon dioxide.
One-third of us regularly produce mildly offensive methane, while the rest do not. Sulfur compounds in very small concentrations are the most common cause of embarrassment. As you have no doubt observed, the exact ingredients of the meal determine the nuances of the final product. Cabbage, for instance, is high in sulfur, and sulfur is a key component in skunk perfume. Designer gases, produced as the bacteria process various foods, add subtleties to the bouquet.