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Originally Posted by Flex
Klimberg et al. (1990) invested the effects of oral glutamine on muscle glutamine metabolism and tumor growth. Twenty-four rats with large sarcomas were pair fed a glutamine-enriched or glutamine-free elemental diet. Results demonstrated that a glutamine-enriched diet increased muscle glutamine content by 60% (P less than 0.05). There were no differences among tumor DNA content, tumor glutaminase activity, or tumor weight and there was no difference histologically in the number of metaphase mitoses/HPF. They concluded that a, “Glutamine-enriched oral diets may replete host glutamine stores and support muscle glutamine metabolism without stimulating tumor growth.”
Glutamine-enriched diets support muscle glutamine metabolism without stimulating tumor growth.
Klimberg VS, Souba WW, Salloum RM, Plumley DA, Cohen FS, Dolson DJ, Bland KI, Copeland EM 3rd.
Department of Surgery, University of Florida College of Medicine, Gainesville 32610.
During a massive review on supplementation with glutamine, from there extensive amount of research on the subject, Alan L. Miller, ND (1999) state that:
"The loss of skeletal muscle glutamine after surgery was illustrated in a group of 19 patients undergoing total hip replacement surgery. Skeletal muscle and plasma glutamine concentration was significantly decreased after surgery, compared to control groups (no surgery) on either bedrest or fasting for four days.39 Glutamine supplementation can attenuate this surgery-induced glutamine depletion. In a study of glutamine and elective abdominal surgery, a glutamine-containing TPN solution (0.285 g glutamine/kg/24 hrs) was given to patients for three days following surgery. Skeletal muscle glutamine levels declined 25 percent, compared to a 40-percent loss in the control TPN group.40"
"A glutamine dipeptide (alanyl-glutamine) was utilized in a study of nitrogen economy in major abdominal surgery patients. Control patients (on standard TPN) lost approximately 36 grams of protein daily, compared to a loss of 14 grams daily in the dipeptide-supplemented TPN group. This amounted to a savings of over 600 grams of protein over the four-day post-operative period. The circulating lymphocyte count remained stable in the supplemented group, versus a 20-percent loss in the control group. Supplemented patients also had improved markers of glutathione levels, and were in the hospital 6.2 days fewer after surgery. The authors estimate the daily requirement of exogenous glutamine in surgical patients to be 12 grams per day, with 25 grams per day needed in severe trauma or infection.41"
Although glutamine is formed in the body from de novo synthesis, and is part of an everyday diet, bodily stores can be overwhelmed by injury, burns, surgery, overtraining, or cancer. Enterocytes, fibroblasts, lymphocytes, and macrophages use glutamine as a metabolic fuel, and the functioning of these cells can be significantly affected with glutamine depletion. Glutamine supplementation via oral, enteral, or parenteral routes increases skeletal muscle glutamine stores and has been shown to improve gut permeability and mucosal morphology, as well as markers of immune function.
Austgen et al. tested the effects of glutamine-enriched total parenteral nutrition were in tumor-bearing rats. Results demonstrated a significant increase in the arterial glutamine level and maintained the skeletal muscle intracellular glutamine concentration (p less than 0.01).
Hammarqvist et al. (1989) tested if the addition of glutamine to total parenteral nutrition after elective abdominal surgery spares free glutamine in muscle, counteracts the fall in muscle protein synthesis, and improves nitrogen balance. Twenty-two patients undergoing elective abdominal surgery were given total parenteral nutrition (TPN) after the operation. The TPN contained either a conventional amino acid solution supplemented with glutamine or a conventional amino acid solution without supplementation. Results demonstrated that the postoperative decrease in the intracellular concentration of free glutamine was less pronounced in the glutamine group (21.8 +/- 5.5%) than in the control group (p less than 0.05). The cumulative nitrogen loss was significantly less in the glutamine group as compared to the control group during the period studied (p is less than .01). This quote from them I thought was excellent, “Administration of glutamine to catabolic patients is advocated”
Addition of glutamine to total parenteral nutrition after elective abdominal surgery spares free glutamine in muscle, counteracts the fall in muscle protein synthesis, and improves nitrogen balance.
Hammarqvist F, Wernerman J, Ali R, von der Decken A, Vinnars E.
His**** et al. (2002) in the journal of Applied Physiology states that:
"Oral glutamine supplementation has been shown to elevate glutamine uptake by skeletal muscle (9), the small intestine, and the splanchnic area (8). In response to acute, exhaustive exercise, oral glutamine supplementation has been shown to attenuate the exercise-induced decrease in plasma glutamine concentration when administered during exercise and in recovery (15). In this situation, glutamine supplementation after exercise may prevent the decrease in glutamine availability to skeletal muscle and further elevate the production and release of IL-6 from skeletal muscle."
Glutamine supplementation further enhances exercise-induced plasma IL-6
N. His****,1,2 E. W. Petersen,1,2 K. Krzywkowski,1,2 J. Boza,4 J. Halkjaer-Kristensen,3 and B. K. Pedersen1,2
From this, they invested the the effect of oral glutamine and glutamine-rich protein supplementation on plasma IL-6 concentration in response to acute exercise. It was hypothesized that supplementation with glutamine and glutamine-rich protein would attenuate the exercise-induced decrease in plasma glutamine concentration and result in a further elevation in plasma IL-6 concentration via enhanced release from working skeletal muscle.
Eight healthy men participated in a randomized, double-blind, crossover study in which they performed 2 h of cycle ergometry at 75% of peak O2 uptake. They received glutamine, glutamine-rich protein, or placebo supplementation at intervals during and 2 h after exercise. Exercise induced an 11-fold increase in plasma IL-6, which was further enhanced by glutamine (18-fold) and glutamine-rich protein (14-fold) supplementation, administered at doses that attenuated the exercise-induced decrease in plasma glutamine concentration.
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"Recent studies have demonstrated that acute exercise elevates plasma levels of interleukin-6 (IL-6) up to 100-fold (12). This increase has been attributed to an increase in the release of IL-6 from contracting skeletal muscle (17). It has been suggested that muscle-derived IL-6 works in a hormone-like fashion, exerting its effect on liver and fat tissue (13); however, the exact mechanisms for the production, release, and biological roles of IL-6 are not known.
The amino acid glutamine is produced predominantly in skeletal muscle and, within muscle, plays a role in the synthesis and breakdown of proteins (14). Glutamine transport in skeletal muscle occurs predominantly via the insulin-sensitive Nm transport system, and it has been shown that muscle glutamine uptake is largely regulated by glutamine availability (4), such that a decrease in arterial glutamine concentration decreases the rate of glutamine uptake into skeletal muscle. Considering its role within skeletal muscle in protein synthesis, it is possible that a decrease in glutamine uptake may inhibit the production of IL-6"
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"Plasma glutamine concentration. There was no effect of time on plasma glutamine concentration in the Gln and Pro experimental groups (Fig. 1; P > 0.05). That is, glutamine and protein supplementation were able to attenuate the exercise-induced decrease in plasma glutamine concentration. However, in the Plac group, there was a significant decrease in plasma glutamine concentration at 2 h after exercise compared with preexercise and immediately after exercise."
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"The main finding of this study was that the exercise-induced increase in circulating IL-6 was further enhanced by glutamine and glutamine-rich protein supplementation, administered at doses that attenuated the exercise-induced decrease in plasma glutamine concentration."
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"In all groups, plasma IL-6 concentration increased in response to acute exercise. This has been shown in previous studies, and this increase is likely due to an increase in the production and release of IL-6 from the working skeletal muscle (17). The augmented increase in plasma IL-6 in the Gln and Pro groups, however, may be explained by an increase in skeletal muscle glutamine uptake, which then stimulates a further increase in IL-6 production. A decrease in skeletal muscle glutamine uptake may result in a decrease in its metabolism within the muscle, lowering the production and release of IL-6, and also attenuate the release of glutamine into the circulation. However, when glutamine concentration is maintained during exercise by supplementation, skeletal muscle uptake is maintained, and the production and release of IL-6 are further enhanced."
Crap indeed.
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