Effect of withdrawal of folic acid supplementation in maintenance hemodialysis patients.

The requirement of patients on maintenance hemodialysis for dietary supplements of folic acid is controversial. High levels of folate carry the risk of toxicity as well as being unnecessary. We followed a group of 41 patients, not receiving erythropoietin, for 16 months after the cessation of folate supplementation (5 mg/day). Diet supplied 60-80 g protein and 120-260 micrograms folic acid/day. Red cell folate levels decreased linearly from a mean of 1931 +/- 888 micrograms/l (+/- SD) to 676 +/- 294 micrograms/l after 6 months before levelling off at 455 +/- 222 micrograms/l after 9 months. Mean values were unchanged 7 months later (491 +/- 319 micrograms/l). No patient developed folate deficiency. Hemoglobin values at 6, 9 and 16 months were slightly higher than the baseline value of 8.3 +/- 1.8 g/dl (p < 0.05). Mean corpuscular volumes were generally within normal limits, and vitamin B12 status was satisfactory. We conclude that folic acid supplements are unnecessary in adequately nourished hemodialysis patients who are not receiving erythropoietin.