Zinc metabolism and taste acuity in renal transplant recipients

To determine the effect of renal transplantation on taste acuity and zinc metabolism, we tested 43 patients with functioning allografts for 2.5 to 96 months. They were tested for taste by the 3-drop stimulus technique. In 30 of them, we determined zinc levels in plasma, hair, and urine. Subnormal plasma and hair zinc, as well as hyperzincuria, was present in all of the 15 patients less than 12 months posttransplant. In contrast, 10 patients who were more than 12 months posttransplant had plasma zinc levels, hair zinc, and urinary zinc excretions in the normal range. Zinc concentrations in plasma and hair of 5 patients who were more than 12 months posttransplant with renal failure, were subnormal and were similar to those in hemodialysis patients. Similarly, taste detection and recognition thresholds for sodium chloride, sucrose, urea, and hydrochloric acid were normal only in patients more than 12 months posttransplant with normal renal function. Plasma zinc, hair zinc, and urinary zinc were not related to prednisone or azathioprine dosage. These results suggest that abnormalities of zinc and taste persist up to 12 months posttransplant and may be related to increased urinary zinc losses.