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 resy nthesis following intense exercise. Eight trained subjects were studied dur ing 3 h of recovery while consuming one of four drinks in random order. Dri nks were ingested in three 500 ml boluses, immediately after exercise and t hen 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 whea t hydrolysate (26% glutamine) and 3) a whey hydrolysate (6.6% glutamine). P lasma glutamine, decreased by approximately 20% during recovery with ingest ion of the control drink, no changes with ingestion of the protein hydrolys ates drinks, and a 2-fold increase with ingestion of the free glutamine dri nks. The rate of glycogen resynthesis was not significantly different in th e four tests: 28 +/- 5, 26 +/- 6, 33 +/- 4, and 34 +/- 3 mmol glucosyl unit s x kg(-1) dry weight muscle x h(-1) for the control, glutamine, wheat- and whey hydrolysate ingestion, respectively. It is concluded that ingestion o f a glutamine/carbohydrate mixture does not increase the rate of glycogen r esynthesis in muscle. Glycogen resynthesis rates were higher, although not statistically significant, after ingestion of the drink containing the whea t (21 +/- 8%) and whey protein hydrolysate (20 +/- 6%) compared to ingestio n of the control and free glutamine drinks, implying that further research is needed on the potential protein effect.