Can I spit yet?
Saliva is the watery and often frothy substance produced in the mouths of humans and most other animals. Saliva is produced in and secreted from the salivary glands. The oral cavity has three main glands: the parotid, sublingual, and submandibular glands, located on both sides of the mouth. Human saliva is composed mostly of water, but also includes electrolytes, mucus, antibacterial compounds, and various enzymes.  As part of the initial process of food digestion, the enzymes in the saliva break down some of the starch and fat in the food at the molecular level. Saliva also breaks down food caught in the teeth, protecting them from bacteria that cause decay. Furthermore, saliva lubricates and protects the teeth, the tongue, and the tender tissues inside the mouth. Saliva is an extremely important component needed to neutralize the mouth and acids produced by bacteria. Healthy saliva is vital to dental health and the prevention of tooth decay. It is sometimes referred to as “the mouth’s blood” as that is how important it is to the health of both hard and soft tissues of the mouth.
There is much debate about the amount of saliva that is produced in a healthy person per day. The estimates range from 0.75 liters per day to 1.5 liters per day. This suggests that the amount produced varies from person to person. It is generally accepted though that while sleeping the amount usually drops to almost zero.
Produced in salivary glands, human saliva is 98% water, but it contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes.
The electrolytes or mineral content include sodium, potassium, calcium, magnesium, chloride, bicarbonate and phosphate. The mucus consists mainly of mucopolysaccharides and glycoprotiens, while the antibacterial compounds include thiocyanate, hydrogen peroxide and immunoglobulin A. There are enzymes that aid in carbohydrate metabolism, fat breakdown once in the stomach, and bacterial cell destruction. There are many cells within saliva, including as many as 8 million human and 500 million bacterial cells per mL.
There are many medications that can affect salivary flow and health. They can pose an increased risk for dental caries and developing cavities. There are also systemic conditions such as Sjogren’s Syndrome, and medical treatments like chemo and radiation therapy that can cause xerostomia, or dry mouth. Taking increased preventive measures to maintain oral health is recommended if any of these situations occur.