Healing Properties Of Saliva

As it is known, saliva is composed of 99% water, proteins, enzymes and some antimicrobial components produced by salivary glands. Primarily, it acts like a lubricant in the mouth to help digestion and speech, but aside from these, it is also beneficial in maintaining good dental health and has antimicrobial functions.

Antimicrobial properties

Our mouth is the entry into our body not only for food but for microorganisms also. The warm and moist surfaces of our oral cavity promote growth of various microorganisms such as bacteria, viruses and fungi. Being a reservoir of so many microbes, the mouth is equipped with such substance as saliva that acts as our body’s first line of defense against pathogenic microorganisms through its antibacterial, antifungal, antiviral and other protecting properties. Salivary flow itself can mechanically remove microorganisms from the mouth, therefore insufficient production of saliva can contribute to formation of dental caries as well as oral yeast and viral infections. Salivary proteins, on the other hand, act in a more complex manner. For instance, salivary lysozyme is capable of bacterial cell wall disruption and neutralization of certain viruses. Iron, an essential mineral for bacterial growth, binds to lactoferrin found in the saliva thus preventing bacteria from multiplying. In addition, lactoferrin also has aggregating action with agglutinins which can bind and clump bacterial cells together for an efficient elimination from the mouth via mechanical action of saliva or swallowing. Mucin and immunoglobulins implement their antimicrobial actions by inhibiting adherence of bacteria into oral surfaces.

Wound healing

Aside from the antimicrobial properties, saliva contains epidermal growth factors, leptin, lysophosphatidic acid, hyaluronan, and histatin that promote wound healing. Moreover, opiorphin in saliva has analgesic effects. Because of these, saliva became a potential subject for studies in wound healing. It has been found that saliva helps to create a favorable environment in the oral cavity for the inflammatory cells which are important during the initial phases of wound healing, because they speed up blood clotting mechanism as a response to injury. Growth factors especially the epidermal growth factor then mediates proliferation of epithelial cells and formation of new blood vessels to replace damaged tissues. Finally, histatin, a salivary protein that is also known for its broad spectrum antimicrobial action against bacteria, viruses and fungi stimulates wound closure. This may explain the underlying principle behind a faster rate of wound healing in the mouth without scarring despite the presence of numerous microorganisms and the correlation between wound licking and healing.

Animal saliva

Instinctively, most animals like cats, dogs and mice lick their wounds. This behavior may be beneficial to a certain extent. Licking can help clean the wound and promote healing. According to studies, dog saliva contains antibacterial substances specifically against S. canis and E. coli bacterial species. Because of this limitation in bactericidal activity, other bacterial species such as Staphylococcal can still infect the wound. Another study conducted on rats discovered that communal wound licking among these rodents speeds up wound healing. However, wound licking may have some disadvantages such as transmission of rabies virus as well as an increased risk of infection.