Taste and nutrition - Part 1

Peer-reviewed | Manuscript received: February 13, 2013 | Revision accepted: April 12, 2013

1. Physiological basis of taste perception

Taste preferences and aversions determine what subjects eat and drink and thus impact on their health and disease risk. How ever, we know relatively little about the principles of how taste affects food choice. The present article discusses the physiological basis of gustation. Two future articles explain the influences of genetic variability and environmental factors on taste perception and nutrition and describe the formation of taste preferences and aversions.

Functional morphology of the peripheral taste system

Flavor

At least tree of our senses contribute to the perception of food. The sense of smell detects the scent of a meal which, through sniffing, reaches the olfactory mucosa via the nostrils or the nasopharynx. Touch and pain report about the texture and temperature of food and the presence of irritants that elicit hot, pungent, astringent, metallic, burning, tingling or electrical sensations. Taste, in the true sense of the word, is restricted to the five basic tastes or taste qualities, sweet, sour, salty, bitter, and umami (savoury). The brain uses all these types of impressions to construct complex flavors. In the following the word taste merely refers to the five basic taste qualities.

Summary

Each taste quality is represented by a specific population of oral chemosensory cells. They are equipped with special receptor molecules which determine the molecular receptive ranges of the sensory cells. Whereas the receptors for salty and sour are, at present, not extensively characterized, a plethora of data exists for sweet, umami and bitter receptors. Although sweet and bitter receptors recognize a broad range of compounds, two different strategies are effective to achieve this goal. In case of the bitter receptors numerous genes have evolved, whereas only two genes code for subunits of the sweet taste receptor. This receptor, however, possesses multiple binding sites to recognize a diversity of sweet substances.
In the taste buds of the tongue sensory cells form assemblies of about 100 cells, which process and integrate taste information with metabolic needs. Sensory afferent nerves transfer gustatory information from the mouth to the brainstem to evoke stereotyped innate attraction or aversion and to prepare the body for digestion. The activity of nerve cells in special areas of the cerebral cortex represents the basic tastes and generates complex flavours by integrating information about taste, smell and texture of food.

Keywords: taste, gustation, physiology, sweet, salty, sour, bitter, umami

Full text PDF (free access)