Taste, Smell and Zinc Metabolism in Patients with Chronic Renal Failure

Abstract

Taste and smell acuity, and zinc concentrations in blood, plasma, red blood cells, and hair were determined in male patients with end stage renal disease (n = 7), male (n – 20) and female (n = 6) patients on maintenance hemodialysis (HD), and male (n = 23) and female (n = 25) control groups. Taste acuity for salt (NaCl), sweet (sucrose), acid (HCl) and bitter (urea) in all 3 patient groups was lower than in the appropriate control group. These differences were significant only for sucrose (male dialysis, p < 0.05), HCl (male uremics not on dialysis, p < 0.01; male dialysis, p < 0.01; and female dialysis, p < 0.05) and urea (male dialysis, p < 0.01). Smell perception was impaired (not significantly) for the male patient groups, but slightly improved (not significantly) for the female patient group. Red blood cell and hair Zn⁺⁺ concentrations were elevated for the male HD group (p < 0.001). The plasma zinc concentration was significantly lowered for the male patient groups (p < 0.05). Age showed a negative correlation with pyridine, NaCl, sucrose, and HO mean detection levels for both male HD patients and control groups. Sensitivity to urea also decreased with age for male HD patient groups, but increased for the male control group. Blood and RBC Zn⁺⁺ concentrations increased and plasma and hair Zn⁺⁺ decreased with age for the male HD patients and the male control group. No correlation was observed between Zn⁺⁺ concentrations and taste and smell mean detection levels.

Relationship of Impaired Olfactory Function in ESRD to Malnutrition and Retained Uremic Molecules

“…5-11 Alterations in taste and smell have also been identified in uremic patients but their relationship to malnutrition is unclear. [12][13][14][15][16][17][18] Normal olfaction is required for full appreciation of the smell and taste of food. Among elderly people in the general population poor odor perception is associated with lower nutrient intake.…”

“…19 Research into olfactory function in ESRD is limited. [13][14][15][16][17][18] Few correlations of olfactory function and nutritional status have been reported. Of significant interest is the finding that odor perception is either the same or worse immediately after hemodialysis but fully restored to that of normal controls after renal transplantation.…”

Impaired Taste Acuity in Patients with Diabetes mellitus on Maintenance Hemodialysis

“…Fernstrom et al [3]described in 1996 that salty taste acuity in HD patients was impaired and bitter taste acuity in CAPD patients was impaired. Further, Vreman et al [9]observed lower taste acuity for sour in 26 HD patients. In contrast, Hurley et al [10]reported that the ability to perceive various salt tastes might not be impaired in patients on renal replacement therapy (HD, CAPD, renal transplant).…”

Nutrition and the Dialysis Prescription

“…As part of a recent study, a food preference questionnaire was administered to dial ysis patients who were averse to the taste of sweets, vege tables, and high-protein foods (red meats, fish, poultry, and eggs) compared with control subjects [62], Although the taste disturbance of dialysis patients has been blamed on zinc deficiency [63], controlled trials of zinc supple mentation have been inconclusive [64], The fishy odor of nitrogenous compounds (secondary and tertiary amines, confirmed by breath analysis), may also contribute to altered taste [65], A well-balanced, nutritious, and tasty diet should be considered a critical component of renal replacement therapy. Hospitalized dialysis patients were reported to have lower nutrient intake when prescribed 'renal' diets than when prescribed regular 'house' diets [66], Given the untoward effects of malnutrition in dialysis patients, the imposition of dietary restriction cannot be thought of as preventing a problem, but rather, trading certain risks for others.…”