Do dialysis patients need substitution with water-soluble vitamins?

In hemodialysis patients, deficiency of water-soluble vitamins has often be en described. Hemodialysis patients are also often protein-calorie-malnouri shed. In addition, some water-soluble vitamins are dialysable. A possible r elation has been postulated between the deficiency of water-soluble vitamin s and a reduced immune response, neuropathy, an impaired amino acid and lip id metabolism. Hyper homocysteinemia can be worsened by a deficiency of cer tain water-soluble vitamins. Recent studies, however, have shown that in vi tamin-supplemented hemodialysis patients supraphysiological levels of water -soluble vitamins were present. Hypervitaminoses of water-soluble vitamins are possible in chronic renal failure patients. High levels of vitamin C ca n aggravate the uremic hyperoxalosis, and high levels of vitamin B6 may act neurotoxic. A supplementation of hemodialysis patients with water-soluble vitamins can not generally be recommended. It only seems necessary for vita min B6 5 - 20 mg/d and vitamin C 100 mg/d when no adequate dietary intake c an be achieved. We recommend to aim for an adequate dietary intake rather t han to supplement vitamins. Folic acid should be given only when a deficien cy is proven. A substitution with vitamin B1 is most likely not necessary. Vitamins B2, B12 and biotin are uniformly described as not deficient in hem odialysis patients.