title: Very low protein diet reduces indoxyl sulfate levels in chronic kidney disease.
abstract: OBJECTIVE
  High levels of indoxyl sulfate (IS) are associated with chronic kidney disease (CKD) progression and increased mortality in CKD patients. The aim of this pilot study was to assess whether a very low protein diet (VLPD; 0.3 g/kg bw/day), with a consequent low phosphorus intake, would reduce IS serum levels compared to a low protein diet (LPD; 0.6 g/kg bw/day) in CKD patients not yet on dialysis.
  
  
  METHODS
  This is a post hoc analysis of a preceding cross-over study aimed to analyze FGF23 during VLPD. Here we performed a prospective randomized controlled crossover study in which 32 patients were randomized to receive either a VLPD (0.3 g/kg bw/day) supplemented with ketoanalogues during the first week and an LPD during the second week (group A, n = 16), or an LPD during the first week and a VLPD during the second week (group B, n = 16 patients). IS serum levels were measured at baseline and at the end of each study period. We compared them to 24 hemodialysis patients (HD) and 14 healthy subjects (control).
  
  
  RESULTS
  IS serum concentration was significantly higher in the HD (43.4 ± 12.3 µM) and CKD (11.1 ± 6.6 µM) groups compared to the control group (2.9 ± 1.1 µM; p < 0.001). IS levels also correlated with creatinine values in CKD patients (R(2) = 0.42; p < 0.0001). After only 1 week of a VLPD, even preceded by an LPD, CKD patients showed a significant reduction of IS serum levels (37%).
  
  
  CONCLUSIONS
  VLPD supplemented with ketoanalogues reduced IS serum levels in CKD patients not yet on dialysis.
authors.affiliation: Department of Pharmacy, University of Salerno, Salerno, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Marzocco
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Dal Piaz
authors.forename: Lucia
authors.initials: L
authors.lastname: Di Micco
authors.forename: Serena
authors.initials: S
authors.lastname: Torraca
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Sirico
authors.forename: Domenico
authors.initials: D
authors.lastname: Tartaglia
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Autore
authors.forename: Biagio
authors.initials: B
authors.lastname: Di Iorio
mesh_terms: D000368:Aged; D000596:Amino Acids / Q000008:administration & dosage*; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D018592:Cross-Over Studies; D018753:Diet, Protein-Restricted; D018450:Disease Progression; D005260:Female; D000089703:Fibroblast Growth Factor-23; D006801:Humans; D007200:Indican / Q000097:blood*; D007651:Keto Acids / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000178:diet therapy*; D016896:Treatment Outcome
chemical_list: D000596:Amino Acids; C000717427:FGF23 protein, human; D007651:Keto Acids; D000089703:Fibroblast Growth Factor-23; D003404:Creatinine; D007200:Indican