How the Sense and Smell of Taste Works

In general, we experience 4 types of tastes, however experts argue on a 5th taste:

  1. Sweet
  2. Sour
  3. Salty
  4. Bitter
  5. Umami

The 5th taste, umami, is the Japanese word similar to savory or delicious. It is actually related to the taste of glutamate and is similar to the taste of broth. This flavor is said to elicit an emotional response.

A woman smelling her cooking
Marc Romanelli / Getty Images

How Does the Sense of Taste Work?

The tastes that we perceive are a two-phase chemical reaction that involves both our mouth and throat (taste) as well as our nose (smell).

We are born with about 10,000 taste buds that are located on our tongue, the roof of the mouth, as well as in our throats. Saliva plays an important role in transporting the tastes we perceive into our taste buds. Each taste bud has about 10-50 cells are responsible for starting the action of taste and are replenished about every 7 to 10 days. We naturally start to lose these taste buds around 50 to 60 years of age.

Our sensation of taste starts with the smells or odors around us that stimulate nerves in a small area located high in the nose. The sweet, sour, or other smells stimulate the brain and affect the actual flavor of the foods we eat. Our sensation of taste continues as the foods we eat mix with saliva to activate the taste buds.

The Common Chemical Sense

However, the taste is more than just a combination of taste (gustatory) and smell (olfactory) as commonly believed. The overall sensation of taste comes from a combination of specialized senses of taste and smell as well as another response known as the common chemical sense.

The common chemical sense can be triggered on surfaces of the mouth, throat, nose, and eyes by the trigeminal nerve. While the system is a natural pain and heat receptor built to help protect the body, it also has a role in providing sharp or strong taste sensations like the burning capsaicin of chili pepper or the cool flavor of mint.

While our tongue and nose send specific taste sensations in the brain, the common chemical sense is not actually a sensation of taste, but still provides a quality that affects our overall experience with tasting foods.

Myths About the Sense of Taste

It was once believed that certain areas of the tongue had concentrations of taste buds responsible for individual sensations of taste. This is no longer believed to be true as the nerves responsible for specific tastes are scattered throughout all regions of the tongue. While there are 5 specific tastes, only 3 specialized nerves have been discovered, so it is believed that combinations of activation account for the tastes that we perceive.

Another common misconception is related to loss of taste. Loss of taste is not necessarily related to a disorder of the mouth, tongue or throat. A loss of smell or other causes can affect your sense of taste. An otolaryngologist (ENT doctor) or another physician may need to test several things before determining the cause of change in the quality of taste.

Are You Losing Your Sense of Taste?

There are many habits and problems that can affect your overall sense of taste. Some you are born with, exposed to (such as cigarette smoke), or happen as a result of a medical condition (i.e. nasal polyps, head injury, middle ear infections, etc).

1 Source
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  1. Taste Disorders. National Institute on Deafness and Other Communication Disorders.

Additional Reading

By Kristin Hayes, RN
Kristin Hayes, RN, is a registered nurse specializing in ear, nose, and throat disorders for both adults and children.