title: Prolonged leucine supplementation does not augment muscle mass or affect glycemic control in elderly type 2 diabetic men.
abstract: The loss of muscle mass with aging has been, at least partly, attributed to a blunted muscle protein synthetic response to food intake. Leucine coingestion has been reported to stimulate postprandial insulin release and augment postprandial muscle protein accretion. We assessed the clinical benefits of 6 mo of leucine supplementation in elderly, type 2 diabetes patients. Sixty elderly males with type 2 diabetes (age, 71 ± 1 y; BMI, 27.3 ± 0.4 kg/m(2)) were administered 2.5 g L-leucine (n = 30) or a placebo (n = 30) with each main meal during 6 mo of nutritional intervention (7.5 g/d leucine or placebo). Body composition, muscle fiber characteristics, muscle strength, glucose homeostasis, and basal plasma amino acid and lipid concentrations were assessed prior to, during, and after intervention. Lean tissue mass did not change or differ between groups and at 0, 3, and 6 mo were 61.9 ± 1.1, 62.2 ± 1.1, and 62.0 ± 1.0 kg, respectively, in the leucine group and 62.2 ± 1.3, 62.2 ± 1.3, and 62.2 ± 1.3 kg in the placebo group. There also were no changes in body fat percentage, muscle strength, and muscle fiber type characteristics. Blood glycosylated hemoglobin did not change or differ between groups and was 7.1 ± 0.1% in the leucine group and 7.2 ± 0.2% in the placebo group. Consistent with this, oral glucose insulin sensitivity and plasma lipid concentrations did not change or differ between groups. We conclude that prolonged leucine supplementation (7.5 g/d) does not modulate body composition, muscle mass, strength, glycemic control, and/or lipidemia in elderly, type 2 diabetes patients who habitually consume adequate dietary protein.
authors.affiliation: Top Institute Food and Nutrition, 6700 AN Wageningen, The Netherlands.
authors.forename: Marika
authors.initials: M
authors.lastname: Leenders
authors.forename: Lex B
authors.initials: LB
authors.lastname: Verdijk
authors.forename: Letty
authors.initials: L
authors.lastname: van der Hoeven
authors.forename: Janneau
authors.initials: J
authors.lastname: van Kranenburg
authors.forename: Fred
authors.initials: F
authors.lastname: Hartgens
authors.forename: Will K W H
authors.initials: WK
authors.lastname: Wodzig
authors.forename: Wim H M
authors.initials: WH
authors.lastname: Saris
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology; D000596:Amino Acids / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000178:diet therapy* / Q000473:pathology / Q000503:physiopathology; D019587:Dietary Supplements; D006801:Humans; D007930:Leucine / Q000008:administration & dosage*; D008055:Lipids / Q000097:blood; D008297:Male; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D008055:Lipids; D007930:Leucine