More detailed composition

Saliva is composed of many different components, whereby the proportions of the respective components differ from unstimulated to stimulated saliva, and the place of production, i.e. which salivary gland is responsible for saliva production, also contributes significantly to the composition. The saliva consists of water for the most part (95%). However, in addition to water, there are also mucins, which are responsible for the viscosity of saliva.

They help to make the saliva more slippery and thus facilitate the swallowing process. In addition, there are many different electrolytes (sodium, potassium, magnesium, iron, fluoride, copper, phosphate, chloride). Fluoride protects the teeth and enamel.

Other small-molecular, solid components found in saliva are urea, uric acid and ammonia. There are also enzymes such as the important digestive enzyme amylase, carbon anhydrase and peroxidase. In addition, important antibodies (immunoglobulin A) and blood group components are contained in saliva.

Dead cells of the oral mucosa (epithelial cells) and germs (microorganisms) are also found in the saliva of a healthy person (physiologically). The predigestion of ingested food already begins in the mouth. Certain enzymes in saliva are responsible for this.

The alpha-amylase helps us digest starch already in the mouth. The amylase works well at a slightly acidic level, for which the HCO3 buffers the saliva to a pH value of about 7.The amylase is inactivated by gastric acid as soon as the food saliva pulp has reached the stomach. Immunoglobulin a and lysozymes are also components of the saliva, it serves the immune defence, this is necessary because food intake is a potentially dangerous contact with the outside world.

Histatin is also present in saliva, which promotes wound healing. Haptocorrin protects vitamin B12 (cobalamin) from the acidic stomach acid, so it can be absorbed in the small intestine with the help of the intrinsic factor. Healthy saliva has a pH value between 6.0 and 6.9 in a normal state (at rest, without food intake).

When stimulated, e.g. by food intake or an olfactory stimulus, saliva can increase to PH values between 7.0 and 7.2. Due to the increased production and thus the faster transport towards the oesophagus and stomach, less sodium ions can be absorbed from the saliva than is the case in a resting state. The result is a slight shift in the pH value towards the alkaline (basic) pH range. When acidic food is eaten, secretion increases the most and the pH value therefore shifts most towards a higher value. The saliva should not be too acidic, otherwise it can attack the teeth.