Limits...
Beneficial effects of resistance exercise on glycemic control are not further improved by protein ingestion.

Breen L, Philp A, Shaw CS, Jeukendrup AE, Baar K, Tipton KD - PLoS ONE (2011)

Bottom Line: Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO.Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON.However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

View Article: PubMed Central - PubMed

Affiliation: School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT

Purpose: To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion.

Methods: Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-¹³C] glucose during an infusion of 6, 6-[²H₂] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT.

Results: Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L⁻¹∶120 min, respectively) compared with CON (90.6±4.1 mmol·L⁻¹∶120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO.

Conclusions: Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

Show MeSH

Related in: MedlinePlus

Tracer enrichments and glucose kinetics over 120 min OGTT.(A) Enrichment of 6, 6-[2H2] and [U-13C] glucose in plasma. Average for all 3 groups presented, n = 24. MPE (%): mole percent excess. (B) Total rate of glucose appearance in plasma (Ra). (C) Contribution of exogenous glucose appearing from the gut (Ra gut) and endogenous glucose production (EGP) to the Ra Total; solid lines indicate Ra gut, dashed arrows indicate EGP. (D) Rate of glucose disappearance from plasma (Rd). Means with different subscripts are significantly different from each other. *: significantly lower Rd for CON compared with EX and EX+PRO. Values are means ±SEM; n = 8 per group.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3119062&req=5

pone-0020613-g004: Tracer enrichments and glucose kinetics over 120 min OGTT.(A) Enrichment of 6, 6-[2H2] and [U-13C] glucose in plasma. Average for all 3 groups presented, n = 24. MPE (%): mole percent excess. (B) Total rate of glucose appearance in plasma (Ra). (C) Contribution of exogenous glucose appearing from the gut (Ra gut) and endogenous glucose production (EGP) to the Ra Total; solid lines indicate Ra gut, dashed arrows indicate EGP. (D) Rate of glucose disappearance from plasma (Rd). Means with different subscripts are significantly different from each other. *: significantly lower Rd for CON compared with EX and EX+PRO. Values are means ±SEM; n = 8 per group.

Mentions: Plasma enrichment of infused 6, 6-[2H2] and ingested [U-13C] glucose are presented in Figure 4A. Ra total, Ra gut, EGP and Rd over time are presented in Figure 4 (B, C, D, respectively). Average plasma glucose tracer kinetics are presented in Table 3. In all groups, plasma glucose Ra total increased over time (P<0.05), peaking 70–90 min after feeding (Figure 4B). There was no difference in the plasma glucose Ra total between groups. Glucose Ra gut demonstrated an increasing contribution to Ra total with time (P<0.05), whereas EGP demonstrated a reduced contribution to Ra total with time (P<0.05; Figure 4C). The increase in Ra gut peaked 70–90 min after feeding, whereas the decline in EGP reached a nadir 90–100 min after feeding. Glucose Rd increased over time in all groups (P<0.05; Figure 4D). Glucose Rd increased by 127±13, 131±15 and 150±18% above basal values for CON, EX and EX+PRO, respectively. Glucose Rd was significantly lower for CON 40–70 min after feeding compared with EX and EX+PRO (P<0.05). Average glucose Rd and whole-body glucose disposal, (Rd expressed as % of Ra total) was significantly lower for CON compared with EX and EX+PRO (P<0.01; Table 3). The time taken for Rd to match the Ra total was greater for CON than EX and EX+PRO (P<0.05). There was no difference in average glucose tracer kinetics between EX and EX+PRO.


Beneficial effects of resistance exercise on glycemic control are not further improved by protein ingestion.

Breen L, Philp A, Shaw CS, Jeukendrup AE, Baar K, Tipton KD - PLoS ONE (2011)

Tracer enrichments and glucose kinetics over 120 min OGTT.(A) Enrichment of 6, 6-[2H2] and [U-13C] glucose in plasma. Average for all 3 groups presented, n = 24. MPE (%): mole percent excess. (B) Total rate of glucose appearance in plasma (Ra). (C) Contribution of exogenous glucose appearing from the gut (Ra gut) and endogenous glucose production (EGP) to the Ra Total; solid lines indicate Ra gut, dashed arrows indicate EGP. (D) Rate of glucose disappearance from plasma (Rd). Means with different subscripts are significantly different from each other. *: significantly lower Rd for CON compared with EX and EX+PRO. Values are means ±SEM; n = 8 per group.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3119062&req=5

pone-0020613-g004: Tracer enrichments and glucose kinetics over 120 min OGTT.(A) Enrichment of 6, 6-[2H2] and [U-13C] glucose in plasma. Average for all 3 groups presented, n = 24. MPE (%): mole percent excess. (B) Total rate of glucose appearance in plasma (Ra). (C) Contribution of exogenous glucose appearing from the gut (Ra gut) and endogenous glucose production (EGP) to the Ra Total; solid lines indicate Ra gut, dashed arrows indicate EGP. (D) Rate of glucose disappearance from plasma (Rd). Means with different subscripts are significantly different from each other. *: significantly lower Rd for CON compared with EX and EX+PRO. Values are means ±SEM; n = 8 per group.
Mentions: Plasma enrichment of infused 6, 6-[2H2] and ingested [U-13C] glucose are presented in Figure 4A. Ra total, Ra gut, EGP and Rd over time are presented in Figure 4 (B, C, D, respectively). Average plasma glucose tracer kinetics are presented in Table 3. In all groups, plasma glucose Ra total increased over time (P<0.05), peaking 70–90 min after feeding (Figure 4B). There was no difference in the plasma glucose Ra total between groups. Glucose Ra gut demonstrated an increasing contribution to Ra total with time (P<0.05), whereas EGP demonstrated a reduced contribution to Ra total with time (P<0.05; Figure 4C). The increase in Ra gut peaked 70–90 min after feeding, whereas the decline in EGP reached a nadir 90–100 min after feeding. Glucose Rd increased over time in all groups (P<0.05; Figure 4D). Glucose Rd increased by 127±13, 131±15 and 150±18% above basal values for CON, EX and EX+PRO, respectively. Glucose Rd was significantly lower for CON 40–70 min after feeding compared with EX and EX+PRO (P<0.05). Average glucose Rd and whole-body glucose disposal, (Rd expressed as % of Ra total) was significantly lower for CON compared with EX and EX+PRO (P<0.01; Table 3). The time taken for Rd to match the Ra total was greater for CON than EX and EX+PRO (P<0.05). There was no difference in average glucose tracer kinetics between EX and EX+PRO.

Bottom Line: Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO.Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON.However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

View Article: PubMed Central - PubMed

Affiliation: School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT

Purpose: To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion.

Methods: Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-¹³C] glucose during an infusion of 6, 6-[²H₂] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT.

Results: Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L⁻¹∶120 min, respectively) compared with CON (90.6±4.1 mmol·L⁻¹∶120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO.

Conclusions: Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

Show MeSH
Related in: MedlinePlus