Effect of vitamin B6 supplementation on plasma oxalate and oxalate removal rate in hemodialysis patients

Abstract

Whether pyridoxine (B6) supplements decrease plasma oxalate concentrations in patients on maintenance dialysis is unresolved. The effect of two dose levels of B6, 0.59 mmol/day (100 mg/day) over 6 months and 4.43 mmol (750 mg) after each dialysis treatment for 4 wk, on plasma oxalate and oxalate removal rate (dialysis plus urinary excretion) was studied in patients on maintenance hemodialysis. In both studies, a control group unsupplemented with B6, who remained on their regular diet, was also studied. The vitamin B6 status of the patients was assessed by the erythrocyte glutamate pyruvate transaminase activity and index before and during supplementation. No decrease in plasma oxalate or oxalate removal rate was found in either study. The plasma oxalate and oxalate removal rates of the unsupplemented hemodialysis patients were not different from those receiving B6 either before or after supplementation. These studies demonstrate that high-dose B6 supplementation does not decrease plasma oxalate concentration in a population of hemodialysis patients.