Gutamine (L-glutamine)
Glutamine is one of the 20 naturally occurring amino acids in dietary protein, specifically it is a conditionally essential amino acid (being elevated to essential during periods of disease and muscle wasting typical of physical trauma). It is sold as an isolated amino acids as well as being found in high levels in dietary meats and eggs. It is found in very high levels in both whey and casein protein.
Glutamine is a very effective intestinal and immune system health compound, as these cells use glutamine as the preferred fuel source rather than glucose.
It is generally touted as a muscle builder, but has not been proven to enhance muscle building in healthy individuals; only those suffering from physical trauma such as burns or muscular wounds (knife wounds) or in disease states in which muscle wasting occurs, such as AIDS. In these individuals, however, glutamine is effective at building muscle and alleviating a decrease in muscle mass typical of the ailment.
Glutamine has been demonstrated in vitro to improve the response to Taxol and may be helpful in reducing the myalgias and neuropathy associated with the taxanes.
Dosage
Supplementation of L-glutamine tends to be dosed at 5 gm or above, with higher doses being advised against due to excessive ammonia in serum. The lowest dose found to increase ammonia in serum has been 0.75 gm/kg, or approximately 51 gm for a 150 lb individual.
Due to the relative inefficacy of glutamine supplementation for increasing muscle mass, the optimal dosage is not known. The above recommended doses are sufficient for intestinal health reasons and for attenuating a possible relative glutamine deficiency (seen in instances of low protein intake or veganism).
For use while on chemotherapy, glutamine 10 gm three times a day is suggested - for this dose powdered formula is available, 5 gm per scoop.
Safety
As a naturally occurring amino acid, glutamine is thought to be a safe supplement when taken at recommended dosages. There is strong evidence that glutamine is safe at levels up to 14 g per day, although higher dosages have been tested without apparent adverse effects.
Nevertheless, those who are hypersensitive to monosodium glutamate (MSG) should use glutamine with caution, as the body metabolizes glutamine into glutamate. Also, because many anti-epilepsy drugs work by blocking glutamate stimulation in the brain, high dosages of glutamine might conceivably overwhelm these drugs and pose a risk to people with epilepsy. Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been determined