As metabolic acidosis increases—as in response to intense training or a high-protein diet—renal uptake of glutamine soars. In fact, one study found that just four days of a high-protein, high-fat diet, was enough to cause a 25 percent drop in glutamine levels in the plasma and muscle tissue. A drop in glutamine levels create a catabolic (muscle wasting) environment. Many call glutamine the fix to stop overtraining (catabolism).
According to many industry experts, the daily intake of glutamine needs to be a higher amount around 20-30 g per day spread apart. This is what the studies show is needed to raise plasma glutamine concentrations to stop Catabolism and help with Growth Hormone levels.
On training days take 10 grams of glutamine 45 minutes before workout and 10 grams after. Taking 10 grams of glutamine right before bed research shows helps with GH levels and staying anabolic while sleeping.
On non-training days, consume 10 grams morning, noon and night.
NOTE; Sustaining an increase in plasma glutamine concentrations is the key to the anti-catabolic effect. Some athletes will take 5 grams every 2-3 hours to insure this happens instead of 10 grams 3 times a day.
A lot of research shows the lack of adverse reactions to supplemental glutamine. This is true even at dosages of 30 grams per day. A 13-week toxicity study showed that there was “no-observed adverse effect level” when they gave the higher dosages.
Glutamine — an overview
- Stimulates the secretion of additional growth hormone.
- Counteracts the negative nitrogen balance keeping the body anabolic after exercise.
- Preserves the muscle glutamine pool, and improves overall nitrogen economy during conditions of stress (life, disease or exercise).
- Protects the body against acidosis.
- Is a major metabolic fuel for the small intestine
- Preserves intestinal integrity and enhances mucosal cellularity and function
- Is a supply of precursors and nitrogenous end products for the synthesis of amino acids
- Is an important carbon and nitrogen source in a number of tissues for a variety of metabolic processes.
- Preserves the muscle glutamine pool, and improves overall nitrogen economy during conditions of stress.
- Conditionally essential amino acid during conditions of catabolism such as stress, injury or starvation.
- Is an effective antagonist of glucocorticoid-mediated muscle atrophy. Counteracts muscle atrophy associated with disease states such as Cushing’s syndrome, cancer, or severe injury.
- Is essential for normal function of lymphocytes, macrophages, and thymocytes which are all important immunologic cells.
- Is highly utilized by cells of the immune system.
Glutamine — Research Information
* A study showed that glutamine stimulates the secretion of additional growth hormone. The results of the study showed a prompt and sustained increase in glutamine levels in the blood, as well as higher plasma bicarbonate levels. Growth hormone concentrations increased by 430 percent and remained above baseline levels for more than an hour and a half. This study shows that even small doses of glutamine optimize the stimulation of hGH production in the pituitary gland and cause its prolonged distribution throughout the body ( Fox, 1996; Welbourne, 1995).
* An intriguing study by Hickson is that the combination of glutamine and exercise can have synergistic and/or additive effects that will completely abolish the catabolic environment and muscle wasting that accompany excessive steroid-hormone (cortisol) levels (Hickson, 1996).
* Oral glutamine ingestion can induce increased growth hormone secretion, which in turn can increase IGF-I. When combined with parenteral nutrition, IGF-I is capable of inhibiting skeletal muscle atrophy resulting from excessive glucocorticoids (Hickson, 1996).
* Nutrient supplementation with glutamine yields beneficial effects on the intestinal mucosa and is also the major metabolic fuel for the small intestine (Naji, 1995; Fox, 1996; James, 1995; Lacey, 1990).
* Glutamine has demonstrated specific anabolic or anticatabolic effects. The provision of exogenous glutamine corrects or prevents the decrease in free glutamine pools characteristic of protein catabolic states and can result in increased body weight gain, improved muscle nitrogen balance, and increased cellularity of gastrointestinal tissues hormones (Symposium, 1990, p. 98s).
* It has been demonstrated that epithelial cells of the small intestine prefer glutamine as a fuel for oxidative metabolism and that long-term glutamine deficiency is accompanied by mucosal atrophy. It was concluded in another study that intestinal mucosa is perfectly equipped to enable an efficient enzyme-catalyzed hydrolysis of glutamine-containing dipeptides either delivered luminally or intravenously. Accordingly, it has been repeatedly demonstrated in human and animal studies that provision of free glutamine or glutamine-containing dipeptides preserved intestinal integrity and enhanced mucosal cellularity and function (Herzog, 1996).
* Studies have established the capacity of the gut to extract glutamine from the blood at a rate comparable with that of the liver (Naji, 1995; Buchman, 1996).
* Studies have suggested that the changes in intestinal glutamine metabolism are intimately tied to the needs of the liver for substrates, and in particular amino acids, to meet the increased demand for enhanced glucose utilization during exercise (Naji, 1995).
* The amino acid glutamine is an important carbon and nitrogen source in a number of tissues for a variety of metabolic processes (Falduto, 1992).
* One of the severe consequences of prolonged exposure to high circulating glucocorticoid (cortisol) levels is muscle wasting (Falduto, 1992).
* Of the total pool of muscle free intracellular amino acids, glutamine represents about 60%. During catabolic stress, a marked reduction (50%) of this pool occurs; the depletion is not reversible by therapeutic efforts or conventional nutritional means (Furst, 1990).
* Reduction of the muscle free glutamine pool is a typical feature of injury and extent and duration of the depletion are proportional to the severity of the illness (Furst, 1990).
* A study concluded that the delivery of adequate amounts of glutamine is essential to maintain the integrity of the mucosa and of the rapidly proliferating cells, to preserve the muscle glutamine pool, and to improve overall nitrogen economy during conditions of stress (Furst, 1990). Furthermore, the addition of glutamine has been shown to partially reverse the jejunal atrophy that accompanies the administration standard total parenteral nutrition solutions without glutamine (Hickson, 1995).
* Several investigations have shown that glutamine supplementation can prevent muscle glutamine depletion to various extents in patients undergoing surgical trauma (Hickson, 1995).
* Glutamine has been identified as a “conditionally” essential amino acid in that its requirement markedly increases in certain organs (i.e., gut) and cell types (mucosal cells) during conditions of catabolism such as injury or starvation (Hickson, 1995).
* Negative nitrogen balance and reductions in total body mass and protein are commonly associated with various catabolic states such as major surgery, injury, glucocorticoid treatment, or other critical conditions. The potential of glutamine as an anticatabolic agent stems from several investigations, in which the addition of glutamine to surgical patients prevented between 40 and 71% of the fall in skeletal muscle glutamine (Hickson, 1995).
* It has been demonstrated that glutamine supplementation is an effective antagonist of glucocorticoid-mediated muscle atrophy and that it can have potential clinical relevance as therapy against muscle atrophy (Hickson, 1995).
* Glutamine supplementation has been shown to counteract the negative nitrogen balance, the decreased concentration and size distribution of skeletal muscle ribosomes, and the muscle glutamine depletion in patients experiencing surgical trauma (Hickson, 1996).
* Recent experiments have demonstrated that glutamine infusion is capable of inhibiting the depression of myosin heavy-chain synthesis and muscle wasting associated with chronically elevated blood glucocorticoid levels in laboratory animals (Hickson, 1996).
* Besides total body mass, a consistent 70% or more prevention of atrophy was observed in all of the predominantly fast-twitch muscles studied with the application of glutamine. The therapeutic effects of glutamine in counteracting this type of muscle atrophy may also have relevance to the muscle wasting associated with various disease states such as Cushing’s syndrome, cancer, or severe injury, in which glucocorticoids are potentially implicated in the physiological responses (Hickson, 1996).
* Glutamine is the substrate that allows the kidney to excrete an acid load and thus protect the body against acidosis. This is accomplished by the production of ammonia, which binds a hydrogen ion, thereby facilitating the urinary excretion of excess protons (Lacey, 1990).
* The data in a study by James et al suggests (1) the mucosal and non-mucosal layers of the lower stomach have substantial potential for synthesizing glutamine, in contrast to the rest of the GI tract, which has little such potential; (2) the potential capacity for glutamine metabolism in the mouth and esophagus appears to be limited; (3) the mucosa of the small intestine, which has the highest capacity for glutamine metabolism derives its glutamine from external sources (James, 1995).
* Hydrolysis of the terminal amide group of glutamine results in formation of glutamate and ammonia. This reaction is critical for release of ammonia to the kidney, an essential step for acid-base homeostasis, or for contributing the amide group for important biosynthetic pathways such as the formation of purines and pyrimidines. In addition, glutamine is a precursor of aspartate (Lacey, 1990).
* Lymphocytes, macrophages, and thymocytes are all important immunologic cells in which glutamine appears to be essential for normal function. There is considerable evidence that glutamine is a nutrient necessary for cell proliferation (Lacey, 1990).
* A study of the safety of glutamine-enriched parenteral nutrient solutions in humans concluded that they are well tolerated with no associated signs of toxicity in normal humans. With this demonstration of the safety of glutamine-enriched nutritional mixtures, the efficacy of such therapy can now be evaluated in various clinical situations. Glutamine-containing parenteral nutrition may be useful in patients undergoing bone marrow transplantation, in the treatment of individuals with inflammatory bowel diseases, or in those patients who have incurred a major thermal or traumatic injury (Lowe, 1990; Symposium, 1990, p. 137S).
* Glutamine is considered to be a potential candidate for use in oral rehydration solutions, the mainstay of treating dehydration due to diarrhoea. This is based on the fact that glutamine stimulates Na absorption in the small intestine of animals and patients with cholera (Nath, 1992).
* Glutamine is highly utilized by cells of the immune system and is considered to be an important fuel for immune cells. In fact, a decrease in plasma glutamine level in vivo has shown to induce am immunosuppression. Furthermore, glutamine is also an important amino acid for a source of purine and pyrimidine nucleotides. Taken together, the hypothesis is advanced that a decreased plasma glutamine concentration after acute or strenuous exercise causes an impairment of immune system such as mitogenesis and NK activity (Moriguchi, 1995).
* Critical illness, whether secondary to accidental injury, severe infection, burns, or diabetic ketoacidosis, is characterized by a loss of body protein. The findings from a study by Muhlbacher, et al, suggest that the high circulating levels of glucocorticoids in these various disease states may be responsible for the changes in glutamine concentrations and metabolism (Muhlbacher, 1984).
* Assessment of glutamine fluxes by stable isotopic methods across the ileum of healthy and infected rabbits shows that under the experimental conditions chosen, glutamine is mostly transported as intact glutamine molecule (Nath, 1992).
* Animal studies have demonstrated that the gastrointestinal tract is the principal organ of glutamine utilization. The ability of the gut mucosa to metabolize glutamine may be even more important during catabolic disease states, when glutamine depletion may be severe and oral nutrition may be interrupted because of the severity of the illness (Symposium, 1990, p. 45S).
* The stress of a major operative procedure combined with general anesthesia is characterized by a fall in circulating and muscle glutamine concentrations postoperatively. The reduction in muscle glutamine content results principally from an accelerated release of glutamine, an event mediated largely by the glucocorticoid hormones (Symposium, 1990, p. 90s).
* Glutamine is an amino acid essential for many important homeostatic functions and for the optimal functioning of a number of tissues in the body, particularly the immune system and the gut. However, during various catabolic states, such as infection, surgery, trauma and acidosis, glutamine homeostasis is placed under stress, and glutamine reserves, particularly in skeletal muscle, are depleted (Rowbottom, 1996).
* With regard to glutamine metabolism, exercise stress may be viewed in a similar light to other catabolic stresses (Rowbottom, 1996).
* Glutamine (GLN) is the most abundant amino acid in the blood and in the free amino acid pool of the body. During starvation and catabolic stress after trauma, surgical procedures, or during sepsis and certain cancer diseases, GLN is delivered from skeletal muscle to the gut, liver, kidney, and various cells of the immune system. In these organs, GLN serves as an energy substrate (intestine), acts as a glucose precursor (intestine, liver), counteracts acidosis (kidney), and is possible responsible for the regulation of intracellular water content in skeletal muscle (Spittler, 1995).
* There is growing evidence that, in certain catabolic disease states, glutamine is a conditionally essential amino acid. Most naturally occurring food proteins contain between 4% and 8% of their amino acid residues as glutamine and therefore less than 10 grams of dietary glutamine is likely to be consumed daily by the average person. In contrast to this usual dietary availability, recent studies in stressed patients indicate that considerably larger amounts of glutamine (20-40 gm/day) may be necessary to maintain glutamine homeostasis after a catabolic insult (Suba, 1992).
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