Deficiencies of vitamins in CAPD patients: the effect of supplementation.

Concentrations of the vitamins B1, B2, B6, B12, C, folic acid, A, E and beta-carotene were determined in blood and 24-h dialysate in 44 CAPD patients. Twenty-five of these patients were studied during chronic treatment (mean 313 days, range 60-1034 days). Nineteen patients were studied during training. In a longitudinal study, 11 patients were analysed again after 77-507 (mean 238) days. In both patient groups a considerable portion of patients (11%-64%) had blood concentrations indicative of a deficiency of the vitamins B1, B6, C and folic acid. The average concentrations of these vitamins were normal in both groups. The only abnormal finding was the mean EGOT activity being deficient in patients on chronic treatment. Mean concentrations of vitamin A were above normal in both groups. In the longitudinal study a significant increase of vitamin B2 and a decrease of vitamin B6 in blood was found. When compared to 24-h excretion in normal urine, loss with 24-h dialysate was low for vitamin B1, normal to relatively high for vitamin B2 and B6, but extremely high for vitamin C and folic acid. The vitamins B12, A, E and carotenoids were hardly detectable in the dialysate. In ten other patients the effect of daily supplementation with 2 mg vitamin B6, 100 mg vitamin C and 400 micrograms folic acid was analysed during a 16-week period. In all patients a significant increase in blood concentrations was obtained. It is concluded that these dosages were sufficient to maintain a normal status of these vitamins in CAPD patients.