Glutamine is the most common amino acid found in your muscles – over 61% of skeletal muscle is Glutamine. Glutamine consists of 19% nitrogen, making it the primary transporter of nitrogen into your muscle cells.
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.
It is synthesized predominantly in skeletal muscle (approximately 90%) by a process facilitated by the enzyme glutamine synthetase from the amino acid glutamate and glutamic acid.
In healthy individuals it can be produced with no problem in the muscle, which is able to produce, store and release glutamine as required to maintain the appropriate glutamine blood concentration.
However, during some situations the production of glutamine homeostasis is threatened, glutamine reserves in skeletal muscle are depleted, and the important functions of this amino acid are inhibited. Such situations would include various forms of catabolic stress ranging from infection, surgery and, importantly, exhaustive exercise!
What Does Glutamine Do?
This amino acid is an important anabolic precursor for muscle growth following exercise In fact it the anabolic effects of glutamine include both an increase in protein synthesis (muscle hypertrophy or increased number of muscle cells) and increases in muscle cell expansion and filling with creatine, water and carbohydrate (muscle cell volumisation or “the pump.
Glutamine is the most important component of muscle protein, and helps repair and build muscle.
Here’s a list of glutamine benefits:
- Glutamine has been linked to protein synthesis. It prevents your muscle from being catabolized (eaten up) in order to provide Glutamine for other cells in the body.
- Glutamine benefits you by replenishing declining Glutamine levels during intense workouts.
- Glutamine may serve to boost your immune system. For bodybuilders, this is important since heavy workouts tend to greatly deplete Glutamine levels. (Glutamine is a primary energy source for your immune system.)
- Glutamine is one of the most important nutrients for your intestines.
Researchers are suggesting that Glutamine is the most important amino acid to the bodybuilder. It provides a component in muscle metabolism and cellular support not shared by any other single amino acid, making the benefits of L-Glutamine supplementation a realistic venture.
Sources and Synthesis
Glutamine is found in high amounts in most meat and animal products, as well as any dairy product or by-product such as whey or casein protein. Levels of glutamine in various foods range from:
- Beef at 4.7% protein where meat in general fluctuates between 4.4% and 4.8%
- Skim Milk at 8.08% protein whereas milk products in general tend to fluctuate between 8.7% and 9.2%
- White Rice at 11.1% protein
- Corn at 16.2% protein
- Tofu at 9.1% protein
- Eggs at 4.3% protein
In order to sustain a positive net protein balance and ensure the above listed benefits of supplementation, orally ingested glutamine can start with 0.1g/ kg of body mass (e.g. 7g for a 70kg individual) and result in a 50% rise in the plasma glutamine concentration 30 minutes following exercise. Return to pre-exercise baseline concentration should occur 1-2 hours following ingestion.
Ingestion alongside a protein source (whey or casein) and a BCAA supplement seems to provide even more superior advantages to glutamine alone, which is perhaps another reason to add a glutamine powder directly to your post exercise shake.
Studies have shown that oral ingestion of up to 28g PER DAY for 6 weeks result in no adverse effects. Furthermore, increasing post exercise dose to 0.65g/ kg of body mass (e.g. 45.5g for a 70kg individual) was also tolerated well by healthy individuals.
How to Take
Bodybuilders should take 10 to 15 grams of L-Glutamine a day – supplementing it 2 to 3 times daily, with each serving at around 5 grams. You should also know that you may already be getting some L-Glutamine in your diet from other supplements you’re taking. Many protein supplements already have some L-Glutamine mixed into it, so read the labels to know for sure. Best times to take L-Glutamine powder is in the morning, after a workout, and at night before bed time.
Supplementation of L-glutamine tends to be dosed at 5 g 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 g/kg, or approximately 51 g for a 150 lb individual.