title: Acute effect of a soy protein-rich meal-replacement application on renal parameters in patients with the metabolic syndrome.
abstract: BACKGROUND
  Soy protein is used for meal replacement therapy in obesity, however the influence on renal function parameters is not adequately investigated. This study evaluates glomerular filtration rate (GFR) and renal plasma flow (RPF) in patients with the metabolic syndrome and healthy controls after ingestion of different amounts of soy protein.
  
  
  METHODS
  10 patients with the metabolic syndrome but no signs of kidney disease and 10 healthy controls ingested 1 g protein/kg body weight of a commercial soy-yoghurt-honeypreparation. The patient group was also given a protein challenge of 0.3 g/kg body weight.
  
  
  RESULTS
  Baseline GFR and RPF both were significantly higher in the patient group (147 ± 34.8 vs. 116 ± 21.1 ml/min, p=0.01 and 848 ± 217 vs. 637 ± 121 ml/min, p=0.02) and were strongly correlated with body weight. Use of different algorithms to estimate GFR resulted in underestimation of GFR, particularly in the patients with the metabolic syndrome. The challenge with an acute protein load of 1g protein per kilogram body weight induced a significant increase in GFR and RPF in healthy controls (GFR: +12.6 ± 11.0 % (p=0.01), RPF: +13.6 ± 15.6 % (p=0.04)) and even more in patients with the metabolic syndrome (GFR: +31.5 ± 32.2 % (p=0.01); RPF: +19.4 ± 22.7 % (p=0.02)). The ingestion of 0.3 g protein/ kg body weight did not induce significant changes.
  
  
  CONCLUSIONS
  Basic renal function is changed in patients with the metabolic syndrome, even without microalbuminuria. In addition, there is an elevated susceptibility for protein load. However, the protein amount recommended for use in soy-protein based meal replacement therapy induced no significant changes.
authors.affiliation: University hospital, Department of Rehabilitative and Preventive Sports Medicine, Freiburg, Germany. peter.deibert@uniklinik-freiburg.de
authors.forename: Peter
authors.initials: P
authors.lastname: Deibert
authors.forename: Lisa
authors.initials: L
authors.lastname: Lutz
authors.forename: Daniel
authors.initials: D
authors.lastname: Konig
authors.forename: Sabine
authors.initials: S
authors.lastname: Zitta
authors.forename: Andreas
authors.initials: A
authors.lastname: Meinitzer
authors.forename: Mara Z
authors.initials: MZ
authors.lastname: Vitolins
authors.forename: Gerhild
authors.initials: G
authors.lastname: Becker
authors.forename: Aloys
authors.initials: A
authors.lastname: Berg
mesh_terms: D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects*; D008297:Male; D024821:Metabolic Syndrome; D008875:Middle Aged; D017595:Renal Plasma Flow / Q000187:drug effects; D030262:Soybean Proteins / Q000008:administration & dosage*; D014280:Triglycerides / Q000097:blood
chemical_list: D004044:Dietary Proteins; D030262:Soybean Proteins; D014280:Triglycerides; D002784:Cholesterol