Taste, smell and zinc metabolism in patients with chronic renal failure

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 HCl 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.