title: Nutrition, vitamin D, and health outcomes in hemodialysis: time for a feeding frenzy?
abstract: OBJECTIVE
  The role of nutrition and nutritional supplementation in dialysis recently has been reinvigorated, with small clinical trials exploring surrogate outcomes and larger epidemiologic studies generating treatment hypotheses requiring further study. The present review focuses on major aspects of nutrition and outcomes in hemodialysis patients: protein and calorie intake and nutritional vitamin D supplementation.
  
  
  RESULTS
  Building on data from small studies, two large, quasi-experimental cohort studies showed significant mortality benefits associated with oral nutritional supplements provided during dialysis, suggesting potential options for ameliorating the protein-energy wasting that is common in dialysis patients and associated with poor outcomes. Multiple cohort studies suggest, both in the general population and in dialysis, that higher 25(OH) vitamin D levels are associated with improved outcomes; however, no major mortality trials exist in dialysis, and the smaller, surrogate studies conducted to date have been disappointing, showing no consistent benefits in surrogate outcomes including inflammation and anemia, despite appropriate responses of vitamin D levels to repletion.
  
  
  CONCLUSIONS
  Nutritional interventions are attractive options for improving outcomes in dialysis patients. Nutritional protein supplements have considerable promise, but require further study, preferably in a large, generalizable pragmatic trial. Small nutritional vitamin D supplementation trials in dialysis have had disappointing results. In the absence of new data, there appears to be no role for routine assessment or repletion of 25(OH) vitamin D deficiency or insufficiency in dialysis.
authors.affiliation: aDivision of Nephrology, Tufts University School of Medicine bTufts Medical Center, Boston, Massachusetts cRutgers-Robert Wood Johnson Medical School, Department of Medicine, Division of Nephrology dDialysis Clinic, Inc., North Brunswick, New Jersey eDialysis Clinic Inc., Nashville, Tennessee, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Weiner
authors.forename: Toros
authors.initials: T
authors.lastname: Kapoian
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Johnson
mesh_terms: D002986:Clinical Trials as Topic; D019587:Dietary Supplements; D006801:Humans; D009752:Nutritional Status / Q000502:physiology*; D006435:Renal Dialysis; D014807:Vitamin D / Q000378:metabolism / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000188:drug therapy*
chemical_list: D014807:Vitamin D