Quote:

---

Originally Posted by cakedonkey View Post
1: Appl Physiol Nutr Metab. 2006 Oct;31(5):518-29.

Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise.

Wilkinson SB, Kim PL, Armstrong D, Phillips SM.

Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.

We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g.kg(-1).h(-1)) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO-EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

PMID: 17111006 [PubMed - indexed for MEDLINE]




1: Eur J Appl Physiol. 2001 Dec;86(2):142-9.

Effect of glutamine supplementation combined with resistance training in young adults.

Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T.

College of Kinesiology, University of Saskatchewan, Saskatoon, Canada.

The purpose of this study was to assess the effect of oral glutamine supplementation combined with resistance training in young adults. A group of 31 subjects, aged 18-24 years, were randomly allocated to groups (double blind) to receive either glutamine (0.9 g x kg lean tissue mass(-1) x day(-1); n = 17) or a placebo (0.9 g maltodextrin x kg lean tissue mass(-1) x day(-1); n = 14 during 6 weeks of total body resistance training. Exercises were performed for four to five sets of 6-12 repetitions at intensities ranging from 60% to 90% 1 repetition maximum (1 RM). Before and after training, measurements were taken of 1 RM squat and bench press strength, peak knee extension torque (using an isokinetic dynamometer), lean tissue mass (dual energy X-ray absorptiometry) and muscle protein degradation (urinary 3-methylhistidine by high performance liquid chromatography). Repeated measures ANOVA showed that strength, torque, lean tissue mass and 3-methylhistidine increased with training (P < 0.05), with no significant difference between groups. Both groups increased their 1 RM squat by approximately 30% and 1 RM bench press by approximately 14%. The glutamine group showed increases of 6% for knee extension torque, 2% for lean tissue mass and 41% for urinary levels of 3-methylhistidine. The placebo group increased knee extension torque by 5%, lean tissue mass by 1.7% and 3-methylhistidine by 56%. We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.

PMID: 11822473 [PubMed - indexed for MEDLINE]



Facts and fallacies of purported ergogenic amino acid supplements.

Williams MH.

Department of Exercise Science, Physical Education, and Recreation, Old Dominion University, Norfolk, Virginia, USA. mwilliam@odu.edu

Although current research suggests that individuals involved in either high-intensity resistance or endurance exercise may have an increased need for dietary protein, the available research is either equivocal or negative relative to the ergogenic effects of supplementation with individual amino acids. Although some research suggests that the induction of hyperaminoacidemia via intravenous infusion of a balanced amino acid mixture may induce an increased muscle protein synthesis after exercise, no data support the finding that oral supplementation with amino acids, in contrast to dietary protein, as the source of amino acids is more effective. Some well-controlled studies suggest that aspartate salt supplementation may enhance endurance performance, but other studies do not, meriting additional research. Current data, including results for several well-controlled studies, indicated that supplementation with arginine, ornithine, or lysine, either separately or in combination, does not enhance the effect of exercise stimulation on either hGH or various measures of muscular strength or power in experienced weightlifters. Plasma levels of BCAA and tryptophan may play important roles in the cause of central fatigue during exercise, but the effects of BCAA or tryptophan supplementation do not seem to be effective ergogenics for endurance exercise performance, particularly when compared with carbohydrate supplementation, a more natural choice. Although glutamine supplementation may increase plasma glutamine levels, its effect on enhancement of the immune system and prevention of adverse effects of the overtraining syndrome are equivocal. Glycine, a precursor for creatine, does not seem to possess the ergogenic potential of creatine supplementation. Research with metabolic by-products of amino acid metabolism is in its infancy, and current research findings are equivocal relative to ergogenic applications. In general, physically active individuals are advised to obtain necessary amino acids through consumption of natural, high-quality protein foods.

PMID: 10410846 [PubMed - indexed for MEDLINE]


Amino acids and endurance exercise.

Hargreaves MH, Snow R.

School of Health Sciences, Deakin University, Burwood, 3125, Australia.

Although skeletal muscle is capable of oxidizing selected amino acids, exercise in the fed and carbohydrate-replete condition results in only a small increase in amino acid utilization. Nevertheless, it may be important to increase the dietary protein requirements of active individuals. There is ongoing debate as to whether the amino acids for oxidation are derived from the free amino acid pool, from net protein breakdown, or a combination of both. There has been interest in the potential ergogenic benefits of amino acid ingestion; however, BCAA ingestion does not appear to affect fatigue during prolonged exercise, there is little support from controlled studies to recommend glutamine ingestion for enhanced immune function, and although glutamine stimulates muscle glycogen synthesis, its addition to carbohydrate supplements provides no additional benefit over ingestion of carbohydrate alone.


PMID: 11255141 [PubMed - indexed for MEDLINE]

The Effects of High-Dose Glutamine Ingestion on Weightlifting Performance

JOSE ANTONIO1, 3, MICHAEL S. SANDERS1, DOUGLAS KALMAN2, DEREK WOODGATE1, and CHRIS STREET1

1. Sports Science Laboratory, University of Delaware, Newark, Delaware 19716, 2. Peak Wellness, Greenwich, Connecticut 06830, 3. Address correspondence to Jose Antonio, Scientific Affairs Department, Nutricia, 6111 Broken Sound Parkway NW, Boca Raton, FL 33487

The purpose of this study was to determine if high-dose glutamine ingestion affected weightlifting performance. In a double-blind, placebo-controlled, crossover study, 6 resistance-trained men (mean ? SE: age, 21.5 ? 0.3 years; weight, 76.5 ? 2.8 kg−1) performed weightlifting exercises after the ingestion of glutamine or glycine (0.3 g?kg−1) mixed with calorie-free fruit juice or placebo (calorie-free fruit juice only). Each subject underwent each of the 3 treatments in a randomized order. One hour after ingestion, subjects performed 4 total sets of exercise to momentary muscular failure (2 sets of leg presses at 200% of body weight, 2 sets of bench presses at 100% of body weight). There were no differences in the average number of maximal repetitions performed in the leg press or bench press exercises among the 3 groups. These data indicate that the short-term ingestion of glutamine does not enhance weightlifting performance in resistance-trained men.

Reference Data:Antonio, J., M.S. Sanders, D. Kalman, D. Woodgate, and C. Street. The effects of high-dose glutamine ingestion on weightlifting performance.

Keywords: amino acid, supplement, nutrition, protein

DOI: 10.1519/1533-4287(2002)016[0157:TEOHDG]2.0.CO;2

---