title: Caloric restriction and L-carnitine administration improves insulin sensitivity in patients with impaired glucose metabolism.
abstract: BACKGROUND
  Reduced circulating and tissue carnitine levels, possibly leading to impaired mitochondrial function, have been postulated to be involved in the pathogenesis of insulin resistance. However, whether L-carnitine administration may improve insulin sensitivity in patients with impaired fasting glucose (IFG) or type 2 diabetes mellitus (DM-2) is still controversial. The aim of the study was to explore the role of L-carnitine supplementation in influencing insulin sensitivity.
  
  
  METHODS
  A randomized controlled study involving adult outpatients was designed. Adult patients referred to the outpatient clinic and within 10 days of the diagnosis of IFG or DM-2 were consecutively enrolled. Exclusion criteria were concomitant antidiabetic therapy and modifications of lifestyle during the previous 4 weeks. Patients were randomly assigned to receive a hypocaloric diet for 10 days (group C; n = 8) or the same dietetic regimen in addition to oral L-carnitine (2 g twice daily) supplementation (group LC; n = 8). Oral glucose tolerance test (OGTT), fasting plasma insulin levels, and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed at the beginning and end of the study. Data were statistically analyzed using the Student t test for paired and unpaired data.
  
  
  RESULTS
  OGTT at 2 hours improved in both groups. Only in the L-carnitine-supplemented group did plasma insulin levels and HOMA-IR significantly decrease when compared to baseline values.
  
  
  CONCLUSIONS
  Considering the role of caloric restriction in increasing the intestinal uptake of carnitine, the results suggest that oral L-carnitine administration, when associated with a hypocaloric feeding regimen, improves insulin resistance and may represent an adjunctive treatment for IFG and DM-2.
authors.affiliation: Department of Clinical Medicine, Sapienza University, Rome, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Molfino
authors.forename: Antonia
authors.initials: A
authors.lastname: Cascino
authors.forename: Caterina
authors.initials: C
authors.lastname: Conte
authors.forename: Cesarina
authors.initials: C
authors.lastname: Ramaccini
authors.forename: Filippo
authors.initials: F
authors.lastname: Rossi Fanelli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Laviano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism; D031204:Caloric Restriction; D002331:Carnitine / Q000494:pharmacology / Q000627:therapeutic use*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000188:drug therapy; D044882:Glucose Metabolism Disorders / Q000097:blood / Q000188:drug therapy*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007328:Insulin; D002331:Carnitine