Zinc Burden Evokes Copper Deficiency in the Hypoalbuminemic Hemodialysis Patients

Abstract

Background: Recent research has focused on the roles of trace minerals such as zinc and copper. In 2017, oral zinc acetate was approved to treat zinc deficiency, and the next year, the Japanese Society for Clinical Nutrition developed the guidelines for diagnosis and treatment for zinc deficiency. Accordingly, hemodialysis patients began receiving zinc acetate when zinc deficiency was diagnosed. However, studies regarding the values of zinc and copper in hemodialysis patients are extremely poor, thus it remains unclear if the guidelines for healthy subjects can be applied to hemodialysis patients. Methods: We conducted a descriptive study, in which 132 patients were subjected to simply examine serum zinc concentration and its association with copper levels in hemodialysis patients (N = 65) versus healthy individuals attending a routine check-up (control group; N = 67) in our hospital. Analyses were performed with BellCurve for Excel (Social Survey Research Information Co., Ltd. Tokyo, Japan). Results: The distribution of zinc level in the hemodialysis group was distinct from that in the control group (P < 0.001). The zinc level was correlated with serum albumin concentration. Zinc concentration was also negatively correlated with serum copper level in both groups. In the hemodialysis group, the upper limit of zinc to avoid copper deficiency was 109.7 μg/dL, and the safety upper limit was 78.3 μg/dL. Conclusions: Hemodialysis patients exhibited a lower level of zinc concentration compared to normal healthy subjects. Since albumin binds to zinc as a carrier, low zinc levels could be attributed to lower level of serum albumin. Importantly, zinc and copper levels were inversely correlated, thus administration of oral zinc acetate could increase a risk for copper deficiency. It might be better to check both zinc and copper values monthly after prescribing zinc acetate.