The impact of smell and taste disorders on dietary habits and nutritional status has received limited research attention. This paper reports findings obtained from questionnaires and diet records completed by 40 healthy subjects and 118 patients with chemosensory dysfunction. Chemosensory disorders were frequently associated with decreases in food acceptability. Although dietary responses to these dysfunctions varied greatly, patients with distorted or phantom smell and/or taste sensations tended to report weight loss whereas those with simple sensory loss were more likely to report weight gain. Indices derived from diet records did not indicate that either group of patients was at substantial nutritional risk, but food frequency responses and estimates of body mass index were consistent with patient reports of changes in dietary patterns and weight. In addition, marked weight change and aberrant dietary practices were noted in individual patients. Thus, there were indications that chemosensory dysfunction may be associated with nutritionally important dietary alterations.

The effect of flavor variety on diet selection, energy intake, weight gain and fat deposition was studied in male rats fed flavored, nutritionally controlled, purified diets in a multichoice "cafeteria" (CAF) arrangement. Serum insulin, L-3,3',5-triiodothyronine (T3) and thyroxine (T4) levels were also determined. Rats fed nutritionally balanced diets containing a variety of preferred flavors and textural forms ad libitum in a CAF design did not consume more energy nor did they gain more weight than rats fed a single choice of nutritionally balanced diet with no modifications in flavor or texture. Feeding high fat, high sucrose diets containing a variety of flavors in a CAF arrangement resulted in higher energy intake, body weight gain, lipid content in fat pads and serum T3 levels than did feeding the nutritionally balanced diet. However, the high fat diet with no added flavors also resulted in an energy intake, body weight gain and lipid content of fat pads at a level equal or close to that produced by the CAF feeding of the flavored, high fat, high sucrose diet. It is therefore concluded that the effect of a variety of food flavors on hyperphagia and fat deposition is of minor importance in purified diets compared to the stimulating effect of the fat in the diet.

Stimulation of the oral cavity immediately elicits salivation, gastric acid secretion and pancreatic exocrine and endocrine secretions that serve to prepare the alimentary canal for digestion, transport and utilization of ingested nutrients. Oropharyngeal-stimulated responses are reliably initiated by the taste and smell of food. These gastrointestinal reflexes, often referred to as anticipatory or cephalic phase responses, are mediated by the autonomic nervous system and are believed to be independent of the postabsorptive effects of ingested nutrients. A common pathway used by cephalic phase responses to trigger gastrointestinal secretions is the vagus. Several studies have also demonstrated that cephalic stimulation activates both the sympathetic and parasympathetic nervous systems and thus, many cephalic-metabolic reflexes may arise indirectly from more general physiological changes that accompany oropharyngeal stimulation. The present studies suggest that oral stimulation results in alterations in intestinal function. Specifically, oropharyngeal stimulation of conscious, unrestrained rats with sucrose increases the uptake of radioactive glucose from the small intestine into the hepatic portal blood.

No abstract