Nutrition and Oral Medicine (Nutrition and Health)

Chapter 8 / Oral Diseases and Conditions 139lead to increased caries risk. Dental and dietetics practitioners should provide patientswith guidelines and refer to each other as needed to maximize patient care.1.6. Nutritional Consequences of Diminished Taste and SmellAdjusted national estimates of the 1994 Disability Supplement to the National HealthInterview Survey reported prevalence rates of 1.4 and 0.6% for olfactory and gustatoryproblems, respectively, that these rates increase exponentially with age (42), and thatolfactory function may decline with age more than taste. Risk factors for diminished tasteand smell include nervous system disorders, chronic renal and liver disease, endocrinedisorders, medication use, and a multitude of disorders affecting the nasal and oropharyngealregions (43). Our capacity to taste and smell allows us to distinguish the flavorand aroma of foods or drinks, whether pleasant or unpleasant. Indeed, alterations in thesesenses significantly impact our quality of life (44).The clinical assessment of olfaction begins with threshold and suprathreshold testing,usually with phenyl ethyl alcohol and pyridine, followed by identification testing of astandard battery of odorants (45). A performance average on the two tests yields a compositescore on a scale from 0 (anosmia) to 7 (normosmia). Weiffenbach has provided athorough review of the assessment of taste (46), which should involve both subjective andobjective tests since there can be discordance between the two. Generally, threshold,suprathreshold, and identification testing is performed for the four standard tastants:sucrose (sweet), sodium chloride (salty), citric acid (acidic), and quinine (bitter).As with other variables that can have a nutritional impact, the nutritional consequencesof diminished taste and smell are difficult to assess. An uncontrolled nutritional assessmentof two cohorts (young: 25–43 yr, and elderly: >60 yr) of patients with smell dysfunctionreported changes in eating habits and a decreased enjoyment of food, although therewas little overall impact on nutritional intake compared to the RDA values (47). Thesefindings were confirmed in a mixed population of 310 patients referred for a chemosensorydysfunction (48 with no diagnosis, 64 subjects with hyposmia, 106 with anosmia,30 with dysosmia, 31 with phantogeusia, and 31 with multiple diagnoses), where a reductionin food enjoyment was noted by 61–90% of the subjects, although overall there wasno significant impact on the nutritional intakes by this population, as measured by 3-ddietary recalls and body weight changes, compared to a control group (48). However, inboth of these studies there was a wide variation of nutritional impact, and a dramaticimpact was noted in some patients with chemosensory disorders; this variation likelydepends on the type, duration, and cause of the disorder, and also by both the individual’sdiet and food-related activities before the onset of the disorder and his or her ability tocompensate. Patients with aversive taste disorders may be more prone to lose weightbecause of the avoidance of certain foods, while, conversely, patients with diminishedtaste or smell may gain weight in an effort to find satisfying food combinations.A common nutritional management strategy for patients with chemosensory disordersis to compensate for missing sensations by increasing the textural quality of foods andstimulating the sensory branches of the trigeminal nerves by adding hot foods such aspepper, horseradish, or mint. For patients with olfactory disorders who can detect primarytaste qualities, compensation with salty, sweet, or acidic foods can greatly enhance foodappreciation, although overuse of salty and sweet foods can have an impact on medicalconditions such as hypertension or diabetes, respectively (49).