Post‐exercise ingestion of different amounts of protein affects plasma insulin concentration in humans

Abstract

The synergistic stimulating effect of combined intake of carbohydrate and protein on plasma insulin concentration has been reported previously. However, it remains unclear whether the amount of protein ingested after exercise affects the concentrations of plasma insulin and amino acids. This study of trained men compared the effects of post-exercise co-ingestion of carbohydrate plus different amounts of whey protein hydrolysates (WPHs) with carbohydrate alone on (1) blood biochemical parameters of carbohydrate metabolism during the post-exercise phase, and (2) endurance performance. Eight trained men exercised continuously for 70 min. Immediately after exercise and 30, 60, 90, and 120 min later, the participants received supplements containing: (1) 17.5 g carbohydrate, (2) 3.0 g WPHs and 17.5 g carbohydrate (L-WPH), or (3) 8.0 g WPHs and 17.5 g carbohydrate (H-WPH). After a 2-h recovery period, the participants performed an endurance performance test. The concentrations of blood glucose were lower and plasma insulin significantly higher in the H-WPH trial compared with the carbohydrate trial. The concentrations of plasma amino acids were increased in a dosedependent manner following ingestion of different amounts of WPHs with carbohydrate. Endurance performance was not significantly different between the three trials. Co-ingestion of carbohydrate and H-WPH was more effective than ingestion of carbohydrate alone for stimulating insulin secretion and increasing the availability of plasma amino acids. These results suggest that plasma concentrations of amino acids during the recovery period are determined by the amount of dietary protein ingested, and that it is necessary to increase the concentration of plasma amino acids above a certain level to stimulate insulin secretion.

Tabata protocol: a review of its application, variations and outcomes

“…After deduplication and language examination, 50 were excluded from the review process; 306 full‐text copies of the remaining studies were obtained and subjected to further evaluation, 276 of these studies were excluded and the reasons for exclusion were annotated. At the end of the process, 30 publications meeting the eligibility criteria were selected for review, of which 22 (Truijens et al., ; Amtmann et al., ; Ravier et al., ; Buchan et al., ,b; Farney et al., ; McRae et al., ; Morifuji et al., ; Rebold et al., ; Fortner et al., ; Invernizzi et al., ; Ma et al., , ; Scribbans et al., ,b; Foster et al., ; Jabbour et al., ; Joanisse et al., ; García‐Hermoso et al., ; Harnish & Sabo, ; Laird et al., ; Logan et al., ; Maté‐Muñoz et al., ) cited the Tabata et al . () and eight (Vuorimaa et al., ; Truijens et al., ; Feriche et al., ; Farney et al., ; Stanley et al., ; Nicolò et al., ; Williams & Kraemer, ; Holmstrup et al., ) cited Tabata et al .…”

“…The number of participants in the studies varied from four (Amtmann et al., ) to 88 (Ma et al., ) with an average of approximately 25 participants. Thirteen studies examined exclusively males (Vuorimaa et al., ; Feriche et al., ; Amtmann et al., ; Ravier et al., ; Farney et al., ; Morifuji et al., ; Scribbans et al., ,b; Stanley et al., ; Nicolò et al., ; Williams & Kraemer, ; Logan et al., ; Maté‐Muñoz et al., ), three exclusively females (McRae et al., ; Holmstrup et al., ; Laird et al., ), whilst the remaining study assessed a mixed sample (Truijens et al., ; Buchan et al., ,b; Rebold et al., ; Fortner et al., ; Ma et al., , ; Scribbans et al., ; Foster et al., ; Jabbour et al., ; Joanisse et al., ; Harnish & Sabo, ). In total, 431 men and 217 women participated in the studies (two studies used the same sample).…”

“…Regarding the type of the study, 16 (53·3%) of the reviewed studies were acute and 14 (46·6%) were chronic studies (Tables S2 and S3). The analyses involved O 2 max (Vuorimaa et al., ; Feriche et al., ; Fortner et al., ; Stanley et al., ; Nicolò et al., ; Williams & Kraemer, ), lactate levels (Feriche et al., ; Amtmann et al., ; Farney et al., ; Fortner et al., ; Invernizzi et al., ; Stanley et al., ; Nicolò et al., ), perceived exertion (Amtmann et al., ; Farney et al., ; Fortner et al., ), heart rate (Farney et al., ; Fortner et al., ; Stanley et al., ; Nicolò et al., ; Williams & Kraemer, ), total work (Farney et al., ; Morifuji et al., ; Scribbans et al., >; Nicolò et al., ; Williams & Kraemer, ; Harnish & Sabo, ), caloric expenditure (Williams & Kraemer, ), oxidative stress (Farney et al., ), blood glucose, insulin and plasma concentration of amino acids (Morifuji et al., ), blood pressure (Buchan et al., ,b; Fortner et al., ; Stanley et al., ; Foster et al., ), fibre‐type distribution, whole‐muscle capillary density (Scribbans et al., >), power output (Foster et al., ; Holmstrup et al., ; Laird et al., ; Maté‐Muñoz et al., ), inflammatory markers (cytokines, interleukin‐6 and interleukin‐10), tumour necrosis factor (TNF‐α) and insulin sensitivity (Harnish & Sabo, ).…”

Restoration of Muscle Glycogen and Functional Capacity: Role of Post-Exercise Carbohydrate and Protein Co-Ingestion

“…This was supported by the same study, whereby free leucine and phenylalanine were added to the wheat protein fraction, and consequently increased insulin concentration relative to a carbohydrate-only beverage [ 121 ]. More recently, a dose-dependent relationship between the amount of whey protein co-ingested during recovery and insulin secretion was found when 0.1 as compared to 0.3 g·kg BM −1 ·h −1 were ingested [ 123 ]. When considered collectively, the available evidence that reported insulinotropic properties with carbohydrate-protein ingestion have included 0.3–0.4 g·kg BM −1 ·h −1 of protein [ 20 , 22 , 33 , 34 , 37 , 124 ].…”

“…Further studies investigated the efficacy of protein feeding during the limited recovery period on subsequent endurance capacity [ 23 , 156 , 157 ] and performance [ 19 , 123 , 159 , 161 ] without the assessment of glycogen concentrations following an initial exercise bout. The findings of these investigations are inconsistent with some showing ergogenic effects of acute carbohydrate-protein feeding of both the capacity to sustain endurance exercise [ 23 ] and performance [ 161 ], while others did not reach similar conclusions [ 19 , 123 , 156 , 157 , 159 ]. Similar to the nutritional considerations regarding muscle glycogen resynthesis, the precise amount of ingested carbohydrate and whether the supplements were matched for energy content may provide a possible explanation for these discrepant findings.…”