Mucus… Here’s The Truth About It

The Purpose Of Mucus
Mucus is something everyone has, and some people wish they had a lot less of the stringy, gooey stuff. Sure, when you have a cold or sinus infection, it can be gross to blow globs of snot into tissue after tissue, but mucus actually serves a very important purpose.
“Mucus is incredibly important for our bodies,” asserts Michael M. Johns III, MD, director of the Emory Voice Center and assistant professor of otolaryngology (head and neck surgery at Emory University). Johns exclaims, “It is the oil in the engine. Without mucus, the engine seizes.”

What Does Mucus Do?
Mucus-producing tissue lines the mouth, nose, sinuses, throat, lungs, and gastrointestinal tract. Mucus acts as a protective blanket over these surfaces. It actually prevents the tissue underneath from drying out. “You have to keep them moist, otherwise they’ll get dry and crack, and you’ll have a chink in the armor.” The latter stated is from Neil L. Kao, MD, (associate professor of medicine at the University of South Carolina School of Medicine).

Mucus Protects The Body
Mucus also acts as a sort of flypaper. It traps unwanted substances (like bacteria and dust) before they can get into the body (particularly the sensitive airways). Johns communicates, “You want to keep that environment, which is a sterile environment, free of gunk.” Johns continues, “Mucus is kind of sticky and thick. It’s got viscosity to it that will trap things.”

Mucus Is The Body’s Helper
But, mucus is more than just sticky goo. It also contains antibodies that help the body recognize invaders (like bacteria and viruses, enzymes that kill the invaders it traps, protein to make the mucus gooey and stringy and very inhospitable, and a variety of cells, among other things). Even when you’re healthy, your body is a mucus-making machine. It churns out about 1 to 1.5 liters of the stuff every day. Most of that mucus trickles down your throat, and you don’t even notice it.

Mucus & Its Consistency
However, there are times when you do notice your mucus. This is usually not because you’re producing more of it, but it’s because its consistency has changed. Johns elaborates, “Typically, the mucus changes character. It gets thicker.” Johns goes on to say, “When it has mass effect, you feel it, and when you feel it, you want to hock.” Some people just naturally have thicker, stickier mucus than others.

Mucus & Allergenic Reactions
It generally takes a bad cold, allergy, or contact with something irritating (like a nuclear-hot chilli pepper) to throw your body’s mucus production into overdrive. For instance, here’s what happens when there’s an allergic response to an offending trigger (such as pollen or ragweed). In your body, mast cells squeeze out a substance called histamine. Histamine triggers sneezing, itching, and nasal stuffiness. The tissue of the mucus membranes starts leaking fluid, and your nose begins to run.

Mucus & Milk
Drinking milk may also make some people produce more mucus. Kao explains, “This is due to gustatory rhinitis, and this is a reflex reaction that’s triggered by eating. Gustatory rhinitis is also why your nose runs when you eat hot chilli peppers.” In some people, milk proteins cause the same type of response. Johns affirms, “Although you may feel like you have more phlegm, you’re not going to worsen a cold by drinking a glass of milk.”

Mucus & Its Color
If you ever paused to have a look at the contents of the tissue after you blew your nose, you may have noticed that your mucus isn’t always perfectly clear. It may be yellow, green, or have a reddish or brownish tinge to it. What do those colors mean?

You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn’t due to bacteria. When you have a cold, your immune system sends white blood cells (called neutrophils) rushing to the area. These cells contain a greenish-colored enzyme, and in large numbers, they can turn the mucus the same color.

Kao shares, “You can have perfectly clear mucus and have a terrible ear and sinus infection.” Johns expresses, “If you do have an infection, you’ll likely also have other symptoms (such as congestion, fever, and pressure in your face, overlying the sinuses).”
Multi-hued mucus also relates to the concentration of mucus. Kao declares, “Thick, gooey mucus is often greenish.” Mucus can also contain tinges of reddish or brownish blood. The latter stated is especially if your nose gets dried out or irritated from too much rubbing, blowing, or picking. Most of the blood comes from the area right inside the nostril, and this is where most of the blood vessels in the nose are located. A small amount of blood in your mucus isn’t anything to worry about, but if you’re seeing large volumes of it, have this checked out.