title: Energy restriction does not prevent insulin resistance but does prevent liver steatosis in aging rats on a Western-style diet.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of long-term energy restriction (ER) on plasma, liver, and skeletal muscle metabolite profiles in aging rats fed a Western-style diet.
  
  
  METHODS
  Three groups of male Sprague-Dawley rats were studied. Group 1 consisted of 2 mo old rats fed ad libitum; group 2 were 19 mo old rats also fed ad libitum; and group 3 were 19 mo old rats subjected to 40% ER for the last 11.5 mo. To imitate a Western-style diet, all rats were given a high-sucrose, very low ω-3 polyunsaturated fatty acid (PUFA) diet. High-resolution magic angle spinning-(1)H nuclear magnetic resonance spectroscopy was used for hepatic and skeletal muscle metabolite determination, and fatty acid profiles were measured by capillary gas chromatography on plasma, liver, and skeletal muscle.
  
  
  RESULTS
  ER coupled with a Western-style diet did not prevent age-induced insulin resistance or the increase in triacylglycerol content in plasma and skeletal muscle associated with aging. However, in the liver, ER did prevent steatosis and increased the percent of saturated and monounsaturated fatty acids relative to ω-6 and ω-3 PUFA.
  
  
  CONCLUSIONS
  Although steatosis was reduced, the beneficial effects of ER on systemic insulin resistance and plasma and skeletal muscle metabolites observed elsewhere with a balanced diet seem to be compromised by high-sucrose and low ω-3 PUFA intake.
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada. Electronic address: Marie.Hennebelle@USherbrooke.ca.
authors.forename: Marie
authors.initials: M
authors.lastname: Hennebelle
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada; Department of Physiology and Biophysics, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Maggie
authors.initials: M
authors.lastname: Roy
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada; Department of Physiology and Biophysics, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Valérie
authors.initials: V
authors.lastname: St-Pierre
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada; Department of Physiology and Biophysics, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Courchesne-Loyer
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Fortier
authors.affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, LabEx TRAIL-IBIO, Université Victor Segalen, Bordeaux, France.
authors.forename: Anne-Karine
authors.initials: AK
authors.lastname: Bouzier-Sore
authors.affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, LabEx TRAIL-IBIO, Université Victor Segalen, Bordeaux, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Gallis
authors.affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, LabEx TRAIL-IBIO, Université Victor Segalen, Bordeaux, France.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Beauvieux
authors.affiliation: Research Center on Aging, Sherbrooke, Quebec, Canada; Department of Physiology and Biophysics, University of Sherbrooke, Sherbrooke, Quebec, Canada; Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Cunnane
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D031204:Caloric Restriction; D002849:Chromatography, Gas / Q000379:methods; D066273:Diet, Western; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D002149:Energy Intake; D005227:Fatty Acids / Q000378:metabolism*; D005234:Fatty Liver / Q000378:metabolism / Q000517:prevention & control*; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005227:Fatty Acids; D007328:Insulin; D014280:Triglycerides
keywords: Aged rats; Calorie restriction; Fatty acid composition; HRMAS (1)H-NMR; Sucrose; ω-3 PUFA