Taste and Smell

We perceive all taste qualities all over our tongue. There can be increased sensitivity to certain qualities in certain areas. Our taste system provides information on the intensity and pleasantness (or unpleasantness) of taste. What people like or dislike in food can change over time. Food preference can be influenced by many different factors, such as physiological status, food context, familiarity, and environment.

Flavor is the term used to describe the complex integration of taste, smell, and chemical irritation of foods in the mouth that add to its “mouthfeel,” ... (Pelletier, 2002).

The tongue is innervated by four cranial nerves that help to contribute taste and irritation of the tongue. This may explain why taste remains strong throughout your lifetime.

The loss of smell is different in that individuals can begin to lose their ability to smell as early as age 40. There can be at 70% deterioration of the ability to smell by the age 70.

When older adults complain that foods don’t seem to “taste” right, it is most likely the loss of smell (which diminishes flavor) that they are describing (Pelletier, 2002). This also leads to a safety issue in that older adults may not be able to tell if food is rancid or if there is a gas leak (mercaptan is added to natural gas to give it a smell but this smell is often below the level that elderly individuals can detect).

The “mushroom-like” small red dots on the tip of the tongue are called fungiform papillae. These are thought to be responsible for an individuals ability to perceive a bitter taste. It has been proposed that individuals with a lot of fungiform papillae are typically picky eaters, with a limited number of foods that they will consume and individuals with smaller amounts of fungiform papillae tend to eat a wider variety of foods.

It is true that a certain smell or odor can bring a vivid memory to mind that is associated with that smell or odor. It may go beyond this as well as it has been shown that within a few hours after birth, infants and mother can recognize each other by smell alone. since chemicals interact with our taste and olfactory receptors to produce the sensations of taste and smell, these senses are called the chemosenses (Pelletier, 2002). In breast feeding babies you are exposing them to the diversity of flavors in beast milk and to smell of the mothers skin where tube fed babies do not experience this type of stimulation. It is thought that there is a period where infants are more sensitive to chemosensory stimulation. If so neonatal units should not only provide oral-motor stimulation but close mother-infant skin contact as well.

Information taken from:

Asha Leader, Oct. 2002

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