AnemiaHow does vitamin D work?

Those undergoing dialysis due to kidney failure generally have high parathyroid hormone (PTH) levels since the kidneys are unable to convert circulating 25(OH)D to the active form of vitamin D, 1,25(OH)2D. 1,25(OH)2D regulates serum PTH levels.

Those on dialysis may have anemia, and it is thought that PTH contributes to this situation. PTH seems to increase the red blood cells’ median osmotic fragility (MOF)1, a measure of likelihood of breaking down quicker than usual.

Clinical studies found that using 1,25(OH)2D in such cases reduced both the PTH levels and the amount of endogenous erythropoietin required to maintain adequate hemocrit levels2.

Page last edited: 08 May 2011


  1. Wu, S. G. Jeng, F. R. Wei, S. Y. Su, C. Z. Chung, T. C. Chang, W. J. Chang, H. W. Red blood cell osmotic fragility in chronically hemodialyzed patients. Nephron. 1998; 78 (1): 28-32.
  2. Brancaccio, D. Cozzolino, M. Gallieni, M. Hyperparathyroidism and anemia in uremic subjects: a combined therapeutic approach. J Am Soc Nephrol. 2004 Jan; 15 Suppl 1S21-4.