title: Liver and muscle glycogen repletion using 13C magnetic resonance spectroscopy following ingestion of maltodextrin, galactose, protein and amino acids.
abstract: The present study evaluated whether the inclusion of protein (PRO) and amino acids (AA) within a maltodextrin (MD) and galactose (GAL) recovery drink enhanced post-exercise liver and muscle glycogen repletion. A total of seven trained male cyclists completed two trials, separated by 7 d. Each trial involved 2 h of standardised intermittent cycling, followed by 4 h recovery. During recovery, one of two isoenergetic formulations, MD-GAL (0.9 g MD/kg body mass (BM) per h and 0.3 g GAL/kg BM per h) or MD-GAL-PRO+AA (0.5 g MD/kg BM per h, 0.3 g GAL/kg BM per h, 0.4 g whey PRO hydrolysate plus l-leucine and l-phenylalanine/kg BM per h) was ingested at every 30 min. Liver and muscle glycogen were measured after depletion exercise and at the end of recovery using 1H-13C-magnetic resonance spectroscopy. Despite higher postprandial insulin concentations for MD-GAL-PRO+AA compared with MD-GAL (61.3 (se 6.2) v. 29.6 (se 3.0) mU/l, (425.8 (se 43.1) v. 205.6 (se 20.8) pmol/l) P= 0.03), there were no significant differences in post-recovery liver (195.3 (se 2.6) v. 213.8 (se 18.0) mmol/l) or muscle glycogen concentrations (49.7 (se 4.0) v. 51.1 (se 7.9) mmol/l). The rate of muscle glycogen repletion was significantly higher for MD-GAL compared with MD-GAL-PRO+AA (5.8 (se 0.7) v. 3.7 (se 0.6) mmol/l per h, P= 0.04), while there were no significant differences in the rate of liver glycogen repletion (15.0 (se 2.5) v. 13.0 (se 2.7) mmol/l per h). PRO and AA within a MD-GAL recovery drink, compared with an isoenergetic mix of MD-GAL, did not enhance but matched liver and muscle glycogen recovery. This suggests that the increased postprandial insulinaemia only compensated for the lower MD content in the MD-GAL-PRO+AA treatment.
authors: Institute for Sport, Physical Activity and Leisure, Carnegie Faculty, Leeds Metropolitan University, Leeds, UK.
authors: Eva
authors: E
authors: Detko
authors: John P
authors: JP
authors: O'Hara
authors: Peter E
authors: PE
authors: Thelwall
authors: Fiona E
authors: FE
authors: Smith
authors: Djordje G
authors: DG
authors: Jakovljevic
authors: Roderick F G J
authors: RF
authors: King
authors: Michael I
authors: MI
authors: Trenell
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000494:pharmacology*; D001628:Beverages / Q000032:analysis; D001642:Bicycling; D002247:Carbon Isotopes; D004311:Double-Blind Method; D005690:Galactose / Q000008:administration & dosage / Q000494:pharmacology*; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D011134:Polysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D011506:Proteins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D011134:Polysaccharides; D011506:Proteins; C008315:maltodextrin; D006003:Glycogen; D005690:Galactose