Serum ascorbic acid in patients undergoing chronic hemodialysis.

Serum presupplementation ascorbic acid levels were subnormal in 8 out of 10 patients undergoing chronic hemodialysis with capillary film and capillary flow dialyzers, the mean duration of treatment being 11 months. Supplementation with 100 mg ascorbic acid daily for two weeks raised the ascorbic acid values to normal in 9 out of 10 patients. After supplementation with 500 mg daily, all patients had ascorbic acid levels exceeding the normal upper limit, and 3 of them had gastrointestinal side-effects. The mean blood pH value, measured in 24 patients on chronic hemodialysis, showed a significant, though slight, decrease during supplementation with 500 mg daily as compared with the mean presupplementation value, but no statistically significant changes were observed in blood bicarbonate, base excess or PCO2 values.