Belly buttons can be filled with any number of things: Dirt, sweat, lint and maybe even some jewelry if that’s what you’re into. But a 2012 study, appropriately titled, A Jungle in There: Bacteria in Belly Buttons are Highly Diverse, but Predictable, found that our tummy holes are also home to 67 species of bacteria on average, since they’re uniquely less exposed — and less frequently washed — than other areas of the skin.
Interestingly enough, some of this bacteria can be put to good use to make — wait for it — cheese (which could explain the less-than-pleasant odor that emits from a dirty button). In 2013, biologist Christina Agapakis teamed up with Sissel Tolaas, an installation artist most widely known for her work with odors, to craft 11 cheeses using the bacteria found in armpits, mouths, toes and belly buttons. While using belly button bacteria to make cheese may sound unorthodox, the bacteria normally used in cheese making, like lactobacillus, are extremely similar to the bacteria on and in our bodies. So by incorporating a process otherwise identical to that of regular cheese, Agapakis and Tolaas’ cheese turned out almost identical to what you’d find in your local market.
But not all of our belly button bacteria can be transformed into tasty goodness. Some can result in yeast infections, which can cause itchiness, redness and odor. Newborns, for instance, can develop yeast infections in their belly buttons after being exposed to their mother’s vaginal yeast during birth. Diabetes and excess abdominal fat can also increase the risk of belly button yeast infections in adults. Generally speaking, however, you shouldn’t have to worry about contracting something nasty in your button so long as you’re even vaguely hygienic.
Speaking of hygiene, the tiny clods of fluff you find stored away in your belly button are particularly unhygienic. A chemical analysis of the stuff, performed by chemist Georg Steinhauser, revealed that it’s more than just cotton from your clothing — it’s also flecks of dead skin, fat, sweat and dust. This mucky combination ends up in your navel more often than not because of the way abdominal hair grows in circles around it: The hair acts like hooked barbs, directing the rancid fluff into your tiny stomach cave.
Fortunately, reducing your risk of developing belly button funk is simple: Use cotton swabs and rubbing alcohol to wipe away any dirt that’s stuck up in there, then simply wash it out with soap and water on a daily basis. That way, you can hide your gum in there without worrying about it getting covered in germs.