Saliva is one of the most neglected factors in your oral and overall health. The normal secretion of saliva is also vital to a healthy mouth, free of cavities and to proper digestion.
Let’s discuss the functions of saliva, the benefits of healthy saliva, and what to do if you produce too much or too little.
What is saliva?
Saliva, or “spit”, is an extracellular fluid produced by the salivary glands in the mouth. Saliva carries important enzymes that break down food particles, which is the first stage of the digestion process. It also delivers minerals and other nutrients to your teeth that teeth use to remineralize.
What is saliva made of?
- Water (95% of the composition of saliva)
- Electrolytes (sodium, potassium, calcium, magnesium, bicarbonate, and phosphates)
- Mucus
- Enzymes
- Immunoglobulins (IgA, etc.)
- Proteins
- Secretory mucins, lactoferrin, lysozyme, peroxidase, and other antibacterial compounds
- Nitrogenous compounds (urea, ammonia, and others)
Healthy saliva is slightly acidic, ranging from about 6-7 pH. This allows saliva to do its job of breaking down food and protecting the mouth from a buildup of bacteria.
Functions of Saliva
1. Clearing Food Debris
Saliva cleans away food debris in the mouth. When you have good saliva flow, food particles are less likely to collect and ferment on your teeth or other areas of your oral cavity.
2. Tasting
Molecules in food that taste of distinct flavors must first be solubilized, or made more soluble (dissolvable) before you can actually taste your food.
Your saliva interacts with taste buds to unmask the tastes offered by different foods.
3. Beginning the Digestive Process
Chewing and swallowing begin digestion, but they would be useless without saliva.
As you chew, the saliva in your mouth binds food particles together into a “bolus,” a slippery substance that easily enters the esophagus. The enzyme amylase breaks down food particles into simpler compounds, which is the first step to digesting food.
The compounds in saliva also protect your throat and esophagus from what would otherwise irritate or damage their sensitive tissue.
4. Supporting the Oral Microbiome
Your saliva is a key factor in a proper balance of good-to-bad microbes in your mouth.
The macromolecule proteins and mucins in saliva destroy, gather (aggregate), and/or cling to certain kinds of oral bacteria. Mucins, in particular, can stop bacteria from attaching to the surfaces inside your mouth and prevent those bacteria (or fungi) from colonizing in a specific area.
These functions help maintain the oral microbiome and preventing pathogens (cavity-causing, or “cariogenic” bacteria) from taking over the mouth.
5. Lubricating the Mouth
Saliva is a seromucous coating, which means it creates a barrier in your mouth between the oral mucosa and anything that enters your mouth. One of the most vital functions of saliva is the lubrication of these surfaces.
6. Buffering Acids
Saliva not only gets rid of food debris that could feed bacteria that cause dental caries (tooth decay), that can break down tooth enamel.
Compounds that help provide a buffer for teeth include:
- Bicarbonate
- Histidine-rich peptides
- Phosphate
- Urea
- Amphoteric proteins and enzymes
How Your Mouth Produces Saliva
Salivary glands produce and secrete saliva through cell clusters called acini. Acini secrete fluid that collects in ducts, where the balance of compounds in saliva is optimized.
These small ducts in the salivary glands all channel into larger ducts and come together into a single duct. That one submandibular duct is what sends 90% of your spit into your mouth.
There are major salivary glands in each side of your mouth:
- Parotid gland (high in your cheek)
- Submandibular gland
- Sublingual gland
Without any outside factors, a small amount of saliva is produced at all times. Additional saliva is produced when:
- You taste and chew food
- You smell certain odors
- You take medications that impact saliva