Special Features > Chewing Well: The Salivary Glands – Partners for Life

We all know how to chew our food well and that this simple act helps digestion. The litre or more of saliva that our mouths produce every day also aids digestion. But chewing our food well and allowing it to be coated with our mouths’ saliva can lead to digestive magic.

The following words are just a reminder of all that chewing, saliva, and chewing combined with saliva
can do.

Chewing

Chewing your food, even without the aid of saliva, can help your body begin to digest your food.
Here are a few examples:

•Chewing well grinds food into small bits, allowing it to be more easily swallowed. Ever try swallowing a poorly chewed food? It actually hurts on the way down the esophagus. You can feel the food tear and scrape your throat.

•Well-chewed bits of food are more easily coated with digestive juices once in the stomach.
The body uses less of its energy to digest well-chewed food than hastily chewed and swallowed food.

•Chewing well also allows the molecules of nutrients from the chewed food to be more quickly released
and assimilated.

•Keeping a food in the mouth longer and chewing it well allows the food’s flavours to be recognized by the tongue. When the tongue recognizes the flavour it sends a message to the brain, which in turn sends messages to the digestive system resulting in the release of the correct digestive juices needed for that food.

Saliva

Saliva can do a few things on its own as well:

•It moistens the molecules of dry foods so that we can taste the foods when we eat them.
We aren’t able to distinguish many flavours in dry food.

•It binds masticated food bits into a bolus, which we can swallow easily.

•It lubricates the esophagus. In fact, the bolus of masticated food never touches or potentially
damages the walls of the esophagus.

•It is important to oral hygiene. The mouth is almost constantly flushed with saliva, which flushes
away food debris and protects your teeth from decay. Saliva can actually kill some bacteria.

But where does all this saliva come from?

You have 3 pairs of major salivary glands and a few minor pairs located throughout you mouth. The salivary glands create saliva, which is then secreted into your mouth via the salivary ducts. Sounds pretty obvious, doesn’t it? Well here are a few of the less obvious facts about the three main salivary glands:

•The first pair of salivary glands to be considered here are the Parotid Glands. These glands, located just under the ears, produce a serous solution. The oral serous solution is clear and watery, and contains the digestive enzyme amylase, also known as ptyalin. It is no wonder that these salivary glands are the ones most associated with carbohydrate digestion. The ducts for these glands are near your upper teeth.

•The Sublingual glands are located under the tongue and produce a saliva that is primarily mucous. Mucous saliva is thick and gluey. It binds the masticated (chewed) food into a bolus as well as lubricating the esophagus. The ducts for these glands are located on the floor of your mouth.

•The Submaxillary glands, also known as the Submandibular glands, are located near the jawbone, secrete both serous and mucous saliva. The saliva reaches your oral cavity via ducts located under your tongue. The Submaxillary glands and the Sublingual glands also produce salivary amylase.

Partners in Health

You now know what chewing well on its own can accomplish, what saliva on its own can accomplish, and even a bit about where that litre (+) of saliva that you produce every day comes from. Now let’s put it all together:

•Chewing well combined with saliva are partners in digestion. We all know that chewing well and mixing your food bits with saliva leads to carbohydrate digestion but did you know eating protein-rich meals actually decreases the amount of salivary amylase produced? Eating a carbohydrate-rich meal leads to a slight increase in the amount of salivary amylase produced in your mouth.

•Saliva acts as a first defense against bacterial infection. By chewing food well and creating more surface area on which the saliva can act, more potential food-borne bacteria can be killed.

•The bicarbonate in saliva may activate the enzyme cellulase found in raw vegetables. The enzyme cellulase digests the fibre cellulose. Together bicarbonate and cellulase begin to digest the raw vegetables. Chewing well also helps to break down the cellulose. However, the combination of the saliva and chewing helps the body to fully digest raw vegetables and receive their nutrients.

Don’t forget – even the most pureed soup or juiced veggies need to be ensalivated. Swish nutrient-rich liquids around in your mouth before you swallow. The carbohydrates present in the soup or juice can be partially digested by your saliva.

I once read that the mouth doesn’t make enough saliva to initiate carbohydrate digestion so if you’re chewing for that reason, don’t bother. Fortunately that ‘idea’ has been thoroughly disregarded by the many who know better. Chewing well and tasting your food is just plain common sense. The fact that our body produces a substance (saliva) that makes chewing, tasting, and swallowing easier is a bonus to our vitality. Chewing well and saliva - each have their own merits. It’s when they work together that we can really appreciate the partnership that nature has created for us.

- Kelly Reith, BA, RHN is a Registered Holistic Nutritionist living, working, and chewing in Toronto, Canada. She can be reached at kellyreith@mac.com