Vitamin Deficiencies in Peritoneal Dialysis
Patients on peritoneal dialysis commonly develop deficiencies in water-soluble vitamins (particularly B vitamins and vitamin C), vitamin D, and trace minerals (zinc, selenium), requiring targeted supplementation based on dietary intake and dialysis losses.
Water-Soluble Vitamins
B-Complex Vitamins
Vitamin B6 (Pyridoxine) is the most critical deficiency to address in peritoneal dialysis patients. Low blood levels occur due to dialysis removal and poor dietary intake, with studies showing 60% of RDA intake in pediatric patients 1. Adult peritoneal dialysis patients should receive 10 mg/day of pyridoxine-HCl supplementation, which is the lowest proven dose to correct deficiency 1, 2. Lower doses (2.5-5 mg/day) are appropriate for infants and young children 1.
Thiamine (Vitamin B1) losses during peritoneal dialysis are minimal compared to hemodialysis, though dietary intake often falls below RDA 1. Supplementation should meet the DRI through diet and/or supplements 1.
Folic acid deficiency occurs from restricted consumption and dialysis losses 3. If lowering homocysteine is the goal, children should receive 2.5-5.0 mg/day of folic acid, though this lowers but does not normalize homocysteine levels 1.
Vitamin B12 (Cobalamin) levels are typically normal in peritoneal dialysis patients, and routine supplementation is unnecessary 1.
Vitamin C (Ascorbic Acid)
Decreased vitamin C levels result from low fruit intake and dialysis losses, with negative mass transfer of 32 mg/day documented in children on automated peritoneal dialysis 1. Combined dietary and supplement intake should meet but not greatly exceed the DRI to avoid oxalate accumulation in plasma and soft tissues 1. Excessive intake (0.5-1 g/day) increases oxalate concentrations and kidney stone risk 1.
Fat-Soluble Vitamins
Vitamin D
Vitamin D deficiency is extremely prevalent in peritoneal dialysis patients, with 97% showing deficiency (<15 ng/mL) and 86% having undetectable levels (<7 ng/mL) in one study 4. Multiple factors contribute: effluent losses, reduced sunlight exposure, low dietary intake of vitamin D-rich foods, and impaired endogenous synthesis 1, 4, 5.
Treatment protocol: Ergocalciferol 50,000 IU orally once weekly for 4 weeks corrects deficiency in most patients 4. For prevention, 800 IU daily for those over 60 years and 400 IU for younger adults is recommended 1. One 50,000 IU capsule monthly achieves the 2,000 IU/day upper limit safely 1.
This regimen improves muscle weakness and bone pain without affecting serum calcium, phosphorus, or PTH levels 4. Vitamin D deficiency independently predicts worse quality of life across all KDQOL-36 subscales 6.
Vitamin A
Vitamin A supplementation should be avoided or severely limited because it accumulates in CKD patients, reaching levels 3-fold higher than controls without supplementation 1. Vitamin A and retinol-binding protein accumulate when GFR is reduced 1. Total intake should be limited to the DRI, with supplementation only for documented very low dietary intake 1.
Vitamin E
Studies show variable vitamin E levels in peritoneal dialysis patients (low, normal, and high) 1. Patients aged 9 years and older should receive the DRI for vitamin E due to its role in alleviating oxidative stress and cardiovascular disease risk 1.
Vitamin K
No intake greater than the DRI is needed unless the patient has poor oral intake and receives long-term antibiotic therapy 1.
Trace Minerals
Zinc
Low serum zinc levels result from dialysis removal and poor intake, with documented intake below RDA in children on peritoneal dialysis 1. Patients should receive the DRI for zinc, with regular monitoring of serum levels, especially in those on low-protein diets 1. Supplementation is reserved for laboratory-confirmed clinical manifestations of deficiency 1.
Selenium
Low serum selenium levels occur despite minimal dialysis removal 1. Selenium-dependent glutathione peroxidase activity decreases with CKD severity 1. Routine supplementation is not recommended, but daily dietary intake should meet the DRI 1. In critically ill patients on kidney replacement therapy, selenium should be monitored and supplemented due to increased requirements and effluent losses 1.
Copper
Low serum copper and ceruloplasmin levels can occur, though copper excess is more common in CKD 1. Intake should be monitored every 4-6 months, with supplementation to the DRI for patients with particularly low dietary intake 1.
Practical Management Algorithm
Assess dietary intake using food records, recognizing that low residual renal function and inadequate urea clearance predict lower micronutrient intakes 7
Provide baseline supplementation with a multivitamin preparation containing thiamine, riboflavin, pyridoxine (10 mg), pantothenic acid, niacin, and ascorbic acid (meeting but not exceeding DRI) 3
Screen vitamin D levels and treat deficiency with ergocalciferol 50,000 IU weekly for 4 weeks 4
Monitor zinc levels every 4-6 months in patients on low-protein diets 1
Avoid vitamin A supplementation unless severe dietary deficiency is documented 1
Monitor water-soluble vitamins and trace elements during critical illness or prolonged kidney replacement therapy, with special attention to vitamin C, folate, thiamine, selenium, zinc, and copper 1