The effect of zinc deficiency on salt taste acuity, preference, and dietary sodium intake in hemodialysis patients

Introduction High sodium intake is the main cause of fluid overload in hemodialysis (HD) patients, leading to increased cardiovascular mortality. High sodium intake is known to be associated with low salt taste acuity and/or high preference. As the zinc status could influence taste acuity, we analyzed the effect of zinc deficiency on salt taste acuity, preference, and dietary sodium intake in HD patients. Methods A total of 77 HD patients was enrolled in this cross-sectional study. Zinc deficiency was defined as serum zinc level with below 70 mu g/mL. The patients were divided into two groups based on serum zinc level. Salt taste acuity and preference were determined by a sensory test using varying concentrations of NaCl solution, and dietary sodium intake was estimated using 3-day dietary recall surveys. Findings The mean salt recognition threshold and salt taste preference were significantly higher in the zinc deficient group than in the non-zinc deficient group. And there was significant positive correlation between salt taste preference and dietary sodium intake in zinc deficient group (r=0.43, P=0.002). Although, the dietary sodium intake showed a high tendency with no significance (P=0.052), interdialytic weight gain was significantly higher in the zinc deficient group than in the non-zinc deficient group (2.68 +/- 1.02 kg vs. 3.18 +/- 1.02 kg; P=0.047). Discussion Zinc deficiency may be related to low salt taste acuity and high salt preference, leading to high dietary sodium intake in HD patients.