Bacteria and Bad Breath

Scientists now know that bacteria and bad breath are intimately linked. It’s usually bacteria, in fact, that produce the very unpleasant odor we all associate with halitosis. What’s not so clear is why the bacteria cause problems in some people’s mouths but not in others: our mouths are full of microorganisms—everyone has millions of them—including bacteria, yeasts, sometimes even protozoa, and in most mouths, they cause no problem at all. Many of the organisms living in our mouths are actually beneficial: among other things, they compete with more harmful organisms that might otherwise cause infection. The ones that produce the bad smell are predominantly anaerobes.

Get too many anaerobes and bad breath will shortly follow. Anaerobes live in the absence of oxygen—some can tolerate a little oxygen while others are exquisitely sensitive to it and die quickly in its presence. When anaerobes metabolize proteins for food, they produce volatile sulfur compounds as a byproduct—gaseous sulfur containing molecules that smell awful. We’ve run into this kind of smell in nature: it’s the smell of rotten eggs, or of organic material rotting in wet oxygen depleted conditions. It explains the link between bacteria and bad breath.

Most people only have a few anaerobes living in the mouth. They exist in small airless locations, like the tight spaces between the teeth, in little pockets in the gums, and in the many grooves on the surface of the tongue, particularly at the back of the mouth. Have just a few anaerobes and bad breath is not a problem; have a lot and the picture changes. This explains why people with decaying teeth and gum disease tend to have trouble—more pockets and spaces available for anaerobes to multiply in, tissues breaking down and providing food for bacteria and bad breath is the inevitable result.

Understanding the relationship between anaerobes and bad breath suggests ways to control it. Keep your teeth and gums in good health; brush and floss regularly to remove food particles, prevent tartar, and clear away any accumulation of organic debris and bacterial growth; brush the tongue, taking care to brush the back of the tongue, a known site for bacteria and bad breath; have oral problems evaluated and treated by a medical professional. For persistent bad breath, choose commercial products that are formulated to reduce the troublesome bacteria through physical removal or by inhibiting growth and survival.