Effects of ingesting protein with various forms of carbohydrate


Effects of ingesting protein with various forms of carbohydrate following resistance-exercise on substrate availability and markers of anabolism, catabolism, and immunity.
Richard B Kreider , Conrad P Earnest , Jennifer Lundberg , Christopher Rasmussen , Mike Greenwood , Patricia Cowan and Anthony L Almada

Journal of the International Society of Sports Nutrition 2007, 4:18doi:10.1186/1550-2783-4-18

Published: 12 November 2007

Abstract (provisional)

Ingestion of carbohydrate (CHO) and protein (PRO) following intense exercise has been reported to increase insulin levels, optimize glycogen resynthesis, enhance PRO synthesis, and lessen the immuno-suppressive effects of intense exercise. Since different forms of CHO have varying glycemic effects, the purpose of this study was to determine whether the type of CHO ingested with PRO following resistance-exercise affects blood glucose availability and insulin levels, markers of anabolism and catabolism, and/or general immune markers.

40 resistance-trained subjects performed a standardized resistance training workout and then ingested in a double blind and randomized manner 40 g of whey PRO with 120 g of sucrose (S), honey powder (H), or maltodextrin (M). A non-supplemented control group (C) was also evaluated. Blood samples were collected prior to and following exercise as well as 30, 60, 90, and 120 min after ingestion of the supplements. Data were analyzed by repeated measures ANOVA or ANCOVA using baseline values as a covariate if necessary.

Glucose concentration 30 min following ingestion showed the H group (7.12 +/- 0.2 mmol/L) to be greater than S (5.53 +/- 0.6 mmol/L; p < 0.03); M (6.02 +/- 0.8 mmol/L; p < 0.05), and C (5.44 +/- 0.18 mmol/L; p < 0.0002) groups. No significant differences were observed among groups in glucose area under the curve (AUC) values, although the H group showed a trend versus control (p = 0.06). Insulin response for each treatment was significant by time (p < 0.0001), treatment (p < 0.0001) and AUC (p < 0.0001). 30-min peak post-feeding insulin for S (136.2 +/- 15.6 uIU/mL), H (150.1 +/- 25.39 uIU/mL), and M (154.8 +/- 18.9 uIU/mL) were greater than C (8.7 +/- 2.9 uIU/mL) as was AUC with no significant differences observed among types of CHO. No significant group x time effects were observed among groups in testosterone, cortisol, the ratio of testosterone to cortisol, muscle and liver enzymes, or general markers of immunity.

CHO and PRO ingestion following exercise significantly influences glucose and insulin concentrations. Although some trends were observed suggesting that H maintained blood glucose levels to a better degree, no significant differences were observed among types of CHO ingested on insulin levels. These findings suggest that each of these forms of CHO can serve as effective sources of CHO to ingest with PRO in and attempt to promote post-exercise anabolic responses.

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J Int Soc Sports Nutr. 2007 Nov 26;4(1):20 [Epub ahead of print]
Effects of creatine loading on electromyographic fatigue threshold during cycle ergometry in college-aged women.Smith AE, Walter AA, Herda TJ, Ryan ED, Moon JR, Cramer JT, Stout JR.

ABSTRACT: The purpose of this study was to examine the effects of 5 days of Creatine (Cr) loading on the electromyographic fatigue threshold (EMGFT) in college-aged women. Fifteen healthy college-aged women (mean +/- SD = 22.3+/-1.7 yrs) volunteered to participate in this double-blind, placebo-controlled study and were randomly placed into either placebo (PL - 10g of flavored fructose powder; n=8) or creatine (Cr - 5g di-creatine citrate plus 10g of flavored fructose powder; n=7) loading groups. Each group ingested one packet 4 times per day (total of 20g/day) for 5 days. Prior to and following supplementation, each subject performed a discontinuous incremental cycle ergometer test to determine their EMGFT value, using bipolar surface electrodes placed on the longitudinal axis of the right vastus lateralis. Subjects completed a total of four, 60 second work bouts (ranging from 100-350 W). The EMG amplitude was averaged over 10 second intervals and plotted over the 60 second work bout. The resulting slopes from each successive work bouts were used to calculate EMGFT. A two-way ANOVA (group [Cr vs. PL] x time [pre vs. post]) resulted in a significant (p=0.031) interaction. Furthermore, a dependent samples t-test showed a 14.5% increase in EMGFT from pre- to post- supplementation with Cr (p=0.009), but no change for the PL treatment (p=0.732). In addition, a significant increase (p= 0.049) in weight (kg) was observed in the Cr group. These findings suggest that 5 days of Cr loading in women may be an effective strategy for delaying the onset of neuromuscular fatigue during cycle ergometry.