Human saliva has long been associated with an instinctive response to injury, leading to the anecdotal belief that it possesses healing capabilities. While it contains beneficial compounds, it is not a substitute for professional medical care. These natural components can support healing in minor situations, but relying solely on saliva for significant injuries carries considerable risks.
Saliva’s Active Ingredients
Saliva is a complex fluid containing more than a thousand proteins and various other molecules. Among these are histatins, small proteins found exclusively in human and higher primate saliva. Histatins, particularly histatin-1, -3, and -5, are recognized for their antimicrobial actions against bacteria and fungi, in addition to regulating the oral microbiome.
Epidermal growth factor (EGF) promotes the proliferation of epithelial cells and is involved in wound closure. Its concentrations in human saliva are lower than in some rodents. Saliva also contains nitrates that break down into nitric oxide on contact with skin. Nitric oxide exhibits antimicrobial activity, inhibiting bacterial growth and inflammation.
Saliva also includes enzymes like lysozyme, which attacks bacterial cell walls, and proteins such as secretory leukocyte protease inhibitor (SLPI), known for its antibacterial, antiviral, and anti-inflammatory effects. Other protective elements include defensins, cystatins, and the antibody IgA. Opiorphin, a natural analgesic peptide, has also shown pain-relieving effects.
Mechanisms of Saliva’s Healing Support
Saliva’s components work together to support natural healing. Histatins promote cell migration and adhesion, crucial for wound closure and tissue regeneration. This contributes to faster, often scar-free healing in oral wounds compared to skin injuries. EGF also aids this process by stimulating epithelial cell proliferation and migration, vital for repairing damaged tissue.
Saliva provides a humid environment, beneficial for healing cell survival and function. This moisture accelerates re-epithelialization, as new skin cells spread more effectively on a moist surface than under a dry scab. Tissue factor in saliva promotes blood clotting, an initial step in stopping bleeding and initiating wound repair.
Saliva’s antimicrobial properties, from ingredients like lysozyme, histatins, and nitric oxide, help fight potential infections in minor wounds. Compounds like SLPI can reduce inflammation, which is necessary for healing but can hinder it if excessive. Opiorphin may offer localized pain relief, contributing to a more comfortable healing experience for small injuries.
When Saliva Isn’t Enough
While saliva offers supportive properties for minor wounds, it is not a comprehensive medical treatment, and relying on it for significant injuries poses considerable risks. The human mouth harbors diverse bacteria, many harmless orally but capable of causing severe infections if introduced into an open wound. Serious infections, including a case where a diabetic man required thumb amputation after licking an injury, highlight this danger.
The concentration of beneficial compounds in saliva may be insufficient for larger or deeper wounds. Saliva lacks the sterility and targeted therapeutic strength of medical treatments. Therefore, for any wound beyond a minor scrape, professional medical attention is important.
It is advisable to seek medical care if a wound shows signs of infection, such as increasing redness, swelling, warmth, pain, pus, or foul-smelling discharge. Other warning signs include red streaks extending from the wound, or fever and chills. Medical evaluation is also needed for deep, large, gaping, or jagged cuts, puncture wounds, or those that do not stop bleeding after five minutes of direct pressure. Individuals with underlying health conditions like diabetes or a weakened immune system should seek medical attention for any wound, as their healing processes may be compromised.