title: Effects of hypocaloric diets with different glycemic indexes on endothelial function and glycemic variability in overweight and in obese adult patients at increased cardiovascular risk.
abstract: OBJECTIVE
  The role of glycemic index of the diet in glucose control and cardiovascular prevention is still not clear. The aim of this study was to determine the effects of hypocaloric diets with different glycemic indexes and glycemic loads on endothelial function and glycemic variability in nondiabetic participants at increased cardiovascular risk.
  
  
  METHODS
  Forty nondiabetic obese participants were randomly assigned to a three-month treatment with either a low glycemic index (LGI; n=19) or high glycemic index (HGI; n=21) hypocaloric diet with similar macronutrient and fiber content. Endothelial function was measured as flow-mediated dilatation (FMD) of the brachial artery before and after dieting. In addition, 48-h continuous subcutaneous glucose monitoring was done before and after dieting in a subgroup of 24 participants.
  
  
  RESULTS
  The amount of weight loss after dieting was similar in both groups. The glycemic index of the diet significantly influenced the FMD (P<0.005). In particular, the change of FMD was 2.3±2.6% following the LGI diet, and -0.9±3.6% after the HGI diet (P<0.005). The mean 48-h glycemia decreased significantly after dietary treatment (P<0.05), but no significant effect of the glycemic index of the diet on results was observed. The glycemic index of the diet significantly influenced the 48-h glycemic variability measured as coefficient of variability (CV%; P<0.001). The CV% decreased after the LGI diet (from 23.5 to 20.0%) and increased after the HGI diet (from 23.6 to 26.6%). The change in percentage of FMD was inversely correlated with the change in the 48-h glycemic CV% (r=-0.45; P<0.05).
  
  
  CONCLUSIONS
  Endothelial function and glycemic variability ameliorate in association with the adherence to an LGI hypocaloric diet in nondiabetic obese persons.
  
  
  BACKGROUND
  ISRCTN56834511.
authors.affiliation: Dipartimento di Medicina Interna e Specialistica (DIMIS), Laboratorio di Nutrizione Clinica; Facoltà di Medicina, Università di Palermo, Policlinico P. Giaccone, Via del Vespro, 129, I-90127 Palermo, Italy. silbus@tin.it
authors.forename: Silvio
authors.initials: S
authors.lastname: Buscemi
authors.forename: Loretta
authors.initials: L
authors.lastname: Cosentino
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rosafio
authors.forename: Manuela
authors.initials: M
authors.lastname: Morgana
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mattina
authors.forename: Delia
authors.initials: D
authors.lastname: Sprini
authors.forename: Salvatore
authors.initials: S
authors.lastname: Verga
authors.forename: Giovam Battista
authors.initials: GB
authors.lastname: Rini
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose; D001823:Body Composition; D050218:Body Fat Distribution; D015992:Body Mass Index; D001916:Brachial Artery / Q000502:physiology / Q000503:physiopathology; D031204:Caloric Restriction; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000517:prevention & control*; D003920:Diabetes Mellitus; D004727:Endothelium / Q000502:physiology* / Q000503:physiopathology; D002149:Energy Intake; D005260:Female; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000503:physiopathology; D050177:Overweight / Q000178:diet therapy* / Q000503:physiopathology; D012307:Risk Factors; D015431:Weight Loss; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin