Caloric Restriction and L-Carnitine Administration Improves Insulin Sensitivity in Patients With Impaired Glucose Metabolism

• Published in: JPEN. Journal of parenteral and enteral nutrition 2010-05, Vol.34 (3), p.295-299
• Main Authors: Molfino, Alessio, Cascino, Antonia, Conte, Caterina, Ramaccini, Cesarina, Fanelli, Filippo Rossi, Laviano, Alessandro
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood Glucose - metabolism; Caloric Restriction; carnitine; Carnitine - pharmacology; Carnitine - therapeutic use; Clinical death. Palliative care. Organ gift and preservation; diabetes mellitus, type 2; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - drug therapy; diet; Emergency and intensive care: metabolism and nutrition disorders. Enteral and parenteral nutrition; Female; Glucose Intolerance - blood; Glucose Intolerance - drug therapy; Glucose Metabolism Disorders - blood; Glucose Metabolism Disorders - drug therapy; Glucose Tolerance Test; Humans; Insulin - blood; Insulin Resistance; Intensive care medicine; Male; Medical sciences; Middle Aged
• ISSN: 0148-6071; 1941-2444
• DOI: 10.1177/0148607109353440

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.