15 - Taste disorders in disease

Abstract

Among the different sensory systems, gustation is one of the most elaborate. In its sensory task, gustation is helped by interactions with other sensory systems (olfaction, vision, audition, and somatosensory, trigeminal and thermal sensations). It allows the detection and identification of soluble compounds which can be ingested or must be avoided. This function is fundamental to ingestive behavior (energy intake and selection of nutrients) in order to meet physiological needs. Taste is also fundamental to the genesis of hedonic sensations and, therefore, the desire to eat (appetite). The tasting step is also the first stage of the digestion, absorption, and storage of nutrients due to anticipatory reflexes. Taste disorders are, therefore, not simple hedonic alterations of the epicurean canon of gastronomy; taste disorders can worsen and even compromise vital functions (malnutrition and aggravation of an underlying disease), and they always reduce quality of life. Many drugs and numerous diseases can cause gustatory loss. The mechanisms leading to taste alteration are varied. In medical practice, taste problems are frequent but not diagnosed often enough, in particular in metabolic syndrome and obesity, in neurodegenerative diseases, and in cancer. Increasing knowledge of taste disorders in disease could improve our understanding of taste pathophysiology, and the prevention of malnutrition by diets adapted to taste impairment.