The act of chewing your food can protect you against infection, researchers from the University of Manchester in the United Kingdom recently found.

Chewing, intended to start the mechanical digestion of food in a person’s mouth as well as begin chemical digestion through the release of enzymes in saliva, also necessarily damages the cells in the mouth. The small abrasions are not serious enough for a person to notice, but cells in the mouth respond to the damage caused by chewing by releasing immune cells.

The immune system includes two types of immunity: adaptive immunity and innate immunity. Innate immunity includes general defenses, such as mucus and skin barriers, that are always ready to fight an infection. Adaptive immunity, on the other hand, includes cells called lymphocytes, which specialize in carrying out targeted attacks on pathogens like bacteria. The adaptive immune response takes a few days to kick in.

Lymphocytes are an important part of the immune system.

Image source: Visuals Unlimited, Inc./Dr. Donald Fawcett & E. Shelton

The immune cells released by the motion of chewing are a type of lymphocyte called T helper cells, which play an important role in the adaptive immune system. These T helper cells (T helper 17, specifically) can identify markers specific to harmful pathogens.

The researchers from the University of Manchester used mice to measure the levels of the T helper cells in the mice’s mouths before and then after simulating the minor damage caused by chewing. After comparing the two measurements, the researchers found that while the increase in T helper cells boosts the immune system, high T helper cell production might also have disadvantages, such as increased gum disease risk.

Although chewing gum, for example, constantly throughout the day won’t necessarily help a person get over a sickness, or even be the best treatment for a sickness, the finding has implications for understanding immunity in the human body. 

Feature Image Source: Eating by Hamza Butt

Michelle Leung

Author Michelle Leung

Michelle Leung is a third-year Molecular Cell Biology (Immunology) and English double major at UC Berkeley. In her free time, she enjoys ice skating and reading. She has been writing and editing for MSO for three years!

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