The effect of free glutamine and peptide ingestion on the rate of muscle glycogen resynthesis in man.
The present study investigated previous claims that ingestion of glutamine and of protein-carbohydrate mixtures may increase the rate of glycogen resynthesis following intense exercise. Eight trained subjects were studied during 3 h of recovery while consuming one of four drinks in random order. Drinks were ingested in three 500 ml boluses, immediately after exercise and then after 1 and 2 h of recovery. Each bolus of the control drink contained 0.8 g x kg(-1) body weight of glucose. The other drinks contained the same amount of glucose and 0.3 g x kg(-1) body weight of 1) glutamine, 2) a wheat hydrolysate (26% glutamine) and 3) a whey hydrolysate (6.6% glutamine). Plasma glutamine, decreased by approximately 20% during recovery with ingestion of the control drink, no changes with ingestion of the protein hydrolysates drinks, and a 2-fold increase with ingestion of the free glutamine drinks. The rate of glycogen resynthesis was not significantly different in the four tests: 28 +/- 5, 26 +/- 6, 33 +/- 4, and 34 +/- 3 mmol glucosyl units x kg(-1) dry weight muscle x h(-1) for the control, glutamine, wheat- and whey hydrolysate ingestion, respectively. It is concluded that ingestion of a glutamine/carbohydrate mixture does not increase the rate of glycogen resynthesis in muscle. Glycogen resynthesis rates were higher, although not statistically significant, after ingestion of the drink containing the wheat (21 +/- 8%) and whey protein hydrolysate (20 +/- 6%) compared to ingestion of the control and free glutamine drinks, implying that further research is needed on the potential protein effect.
van Hall
G
G
Department of Human Biology, Maastricht University, The Netherlands. RH01769@RH.DK
Saris
W H
WH
van de Schoor
P A
PA
Wagenmakers
A J
AJ
D000284:Administration, Oral; D000328:Adult; D004040:Dietary Carbohydrates / Q000378:metabolism; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology*; D005973:Glutamine / Q000494:pharmacology*; D006003:Glycogen / Q000096:biosynthesis*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D010807:Physical Endurance / Q000502:physiology*
D004040:Dietary Carbohydrates; D010455:Peptides; D005973:Glutamine; D006003:Glycogen