Chew That Food!

I recently read an interesting view of chewing your food, written by Honor Whiteman. We’ve all heard that little phrase all during our childhood from our parents. “Chew that food!” A new study advises us this is very wise advice. It is found by researchers that chewing food prompts the release of an immune cell that can protect against infection. It was published recently in the journal Immunity. They found that chewing food (known as mastication) could stimulate the release of T helper 17 (Th17) cells in the mouth.

These Th17 cells form a part of the adaptive immune system that uses specific antigens to defend us against potentially harmful pathogens, while enduring the “friendly” bacteria that can be beneficial to health.

Study team leader Dr. Joanne Konkel of the University of Manchester in the United Kingdom, reports that in the gut and the skin the Th17 cells are produced through the presence of friendly bacteria. They note that the mechanisms by which the Th17 cells are produced in the mouth have been unclear.

Chewing can induce a protective immune response in our gums, according to Dr. Konkel and colleagues. The mechanical force required by mastication leads to physiological abrasion and damage in the mouth. The team set out to investigate whether such damage might play a role in oral Th17 cell production. They came to their findings by feeding weaning mice soft-textured foods, which required less chewing, until they reached 24 weeks of age. Then at 24 weeks, the release of Th17 cells in the rodents’ mouths was measured. There was a significant reduction in oral Th17 cell production noted, which the team speculated was down to a reduction in mastication-induced physiological damage.

To confirm their theory they found that increasing the levels of physiological damage in the rodents’ mouths – by rubbing the oral cavity with a sterile cotton applicator – led to an increase in the production of Th17 cells. They believe these findings indicate that chewing food may help to protect us from illness. To quote Dr. Joanne Konkel, “The immune system performs a remarkable balancing act at barrier sites such as the skin, mouth and gut by fighting off harmful pathogens while tolerating the presence of normal friendly bacteria.” She further indicates that unlike at other barriers, the mouth has a different way of stimulating Th17 cells; not by bacteria but by mastication.

There is a downside of excessive mastication, however. Too many of these cells can increase the risk of periodontitis or gum disease, which has been associated with numerous other health conditions, including diabetes and rheumatoid arthritis. The study also revealed that long-term exposure to physiological damage caused by mastication could exacerbate the effects of periodontitis. Compared with mice fed soft food, the mice fed hard food showed more mastication-induced physiological damage in their mouths and increased periodontal bone loss.

They do still believe that their findings could lead to new strategies to combat an array of illnesses. Because inflammation in the mouth is linked to development of diseases all around the body, understanding the tissue-specific factors that regulate immunity at the oral barrier could eventually lead to new ways to treat multiple inflammatory conditions.

Dr Fredda Branyon