Our ancestors understood that certain foods or odors were dangerous and must be avoided. Today we still use the sensations of taste and smell as warning signals to avoid problems.
Think of the mother who returns from shopping with her four y/o daughter, opens the door to her apartment, walks in and shouts, “I smell gas!”
Or the teenager standing next to the kitchen sink, taking a sip of milk and in a blink of the eye spits it out, “This milk is sour” and throws the rest of it out.
The chemical sensations of taste and smell also help us experience the enjoyment of food, aromas and flavor. Foods that taste good, smell good and make us feel good can have a lasting emotional impact on our lives.
Consider a young couple who decide to celebrate their engagement in a fancy restaurant. The food is delicious, the wine complements the food, the flowers add to the perfect ambience. For desert, they have fun deciding which of the seven ice cream flavors to choose from the menu. They enjoy a memorable evening on this starry night
What’s going on? What‘s the connection or is there any?
Taste and smell are part of a system that alerts us to pleasure or danger. Aromas, fragrances and odors relate to our sense perception by way of the Olfactory nerve (smell nerve).
Olfactory cells and nerve receptors are located in the upper and back parts of the nose. They respond to different chemicals in the air and transmit signals to the brain for interpretation, allowing us to detect the fragrance of flowers or the smell of smoke or gas. These cells have the capacity to regenerate.
The sensation of taste refers to five primary tastes — sweet, sour, bitter, salty and umami. Umami will be discussed below. Gustatory cells are clustered into taste buds which are located predominately on the tongue. These sensitive cells are also found on the inside and back of the mouth and other parts of the body.
Saliva is needed to break down the chemicals components in food we ingest and this helps us distinguish the five primary sensations of taste. Taste bud receptors relay the information to the brain for interpretation as to whether food tastes good or bad, fresh or rancid.
Taste and flavor are not the same sensations…
Flavor, the quality of food or drink occurs when the sensations of taste, smell and texture (feel of food) come together. The brain fuses these sensations and it gives food or drink a special signature.
Someone might say, “I love the flavor of roasted peppers,” or another, “I like the flavor of chocolate chip cookies.”
Have you ever burned your tongue on hot coffee or hot soup? The hot coffee killed thousands of taste buds. We have about ten thousand onion-shaped taste buds and each one is made up of from 50 to 150 taste (gustatory) cells. Fortunately, they grow back.
The lifespan of a taste bud is 10 to 12 days and it regenerates and replaces those taste buds that die. As we get older, the total number of taste buds decreases and so does our sensation of taste. Taste and smell are part of a system that contributes to our appreciation of food, drink and flavor. They also serve as early warning signals alerting us to potential danger. The primary tastes are important parts of this pleasure — danger system.
Five Tastes
The five primary sensations, sweet, sour, bitter, salty and umami are not isolated tastes but rather overlap one another.
- Sour Taste
A sour taste in the morning might be due to stomach acid flowing up into the back of the throat and mouth. Sour taste has a protective side to it. A bite into an unripen apple or a sip of sour milk warns us to stop eating and drinking. - Sweet Taste
The sweet taste is caused by different types of chemicals such as sugars and alcohol. It’s a pleasurable sensation and the average person is wired to love sugar. Babies love sugar and that may be one reason why some baby food manufacturers load up their food products with sweeteners. - Bitter Taste
Bitter taste is the opposite of sweet taste and is generally considered unpleasant. Most poisons taste bitter and are caused by more than a single agent. Many medications have a bitter taste. Yet, we don’t seem to mind the bitter taste of coffee and dark chocolate. - Salty Taste
Salt is a flavor enhancer when added to food. When you salt certain foods, either a steak or a tomato, it causes aromatic chemicals of the food into the air giving the food more aroma and flavor. Salt cuts down on the bitterness of food and the sodium part is essential for the cells in our body to work normally. We need to include iodized salt in our diet for our thyroid. - Taste of Umami
Umami has been portrayed as having a “pleasant, savory taste.” The savor of umami is due to free glutamate. Glutamate is an amino acid, one of the building blocks of proteins. When MSG, monosodium glutamate is added to soup, people have offered their description of the soup as being flavorful.
When we bite into a ripe tomato or chew meat, we enjoy the experience in part because of the freed glutamate. Aged parmesan cheese, anchovies a good veal stock, are loaded with free glutamate. If you enjoyed an outstanding dinner and it did not taste sweet, bitter, sour or salty, the deliciousness might be due to Umami.
There’s more to taste than just taste buds. Eighty percent of what most people consider taste is related to the sense of smell. A small step in the appreciation of dining might be to consciously taste food & drink. The primary tastes, aromas and flavors will become evident. Who knows, we might eat less, more nutritiously, be healthier and truly enjoy the experience.
REFERENCES
- Stuckey, Barb; Taste What You’re Missing; 2012; Simon and Schuster
- Reed, Danielle R.; Diverse Tastes; Genetics of sweet and bitter perception; Physiol. Behav; Jun30, 2006.
- Bromley, Steven M.; Smell and Taste Disorders; Am. Fam. Physician; Jan 15, 2000
- Guyton and Hall, Textbook of Medical Physiology, 2016. W. B. Saunders and Co.
- Costanzo RM; Regeneration of Olfactory Receptor Cells; Pub Med; Ciba Foundation Symposium, 1991
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.