Why Glutamine?

Dec 9, 2020

 by Thomas Sampson

Why Glutamine?

Glutamine is the MOST abundant amino acid in both your muscle fiber and plasma. Glutamine acts as the primary fuel source of the small intestine and the cells of your immune system (that is a big deal)!

Glutamine also affects reproduction and multiplication of cells, both of which are required for optimal immune response to foreign substances like bacteria, viruses, and tumor cells.

Your liver and brain also use glutamine. As much as 40% of the glutamine you ingest via protein consumed is used by your gastrointestinal tract. This means glutamine circulating in your blood must be produced by the liver and muscles.

Since muscle is the dominant supplier, and because muscle provides a store of glutamine, plasma glutamine (the stuff in your intestines) becomes the link between skeletal muscle and the immune system. If at any time, the intestinal tract calls for energy to ward off a foreign substance like a virus or bacteria, this can cause a high rate of energy expenditure even in a resting state. If production of glutamine becomes impaired so does the immune system.

Glutamine is only obtained or produced by the body in a hand full of ways:

  • Uptake of glutamine from the blood stream accounts for somewhere between 18-65% of production.
  • Breakdown of muscle protein produces glutamine directly and this is what leads to muscle catabolism if there is not sufficient glutamine present when needed for immune function.
  • Breakdown of muscle protein also produces amino acids, glutamate, aspartate, and asparagine that are used to synthesis of glutamine. It is also thought that glutamine can be produced using carbohydrates.
  • Finally, supplementation. It definitely wont hurt to add some extra glutamine in its raw form around the times of your workouts if you are someone who works out hard and wants to keep your lean muscle mass and also your immune system running strong.

“Extra” Glutamine maintains muscle when the body’s need for glutamine exceeds its natural production. Something like prolonged exercise for instance could cause the activity of the immune response cells to be suppressed. We like to refer to this as metabolic stress. During the times of metabolic stress, increasing the amount of glutamine available to the body would increase protein synthesis, maintain glutamine production, ward off catabolism (metabolism of muscle mass) and therefore maintain the activity of the body’s immune response.

If Glutamine is not available muscle catabolism begins and leads to a reduction in plasma glutamine available (the stuff in your intestines used to power your immune system), leaving the body’s immune system more susceptible to invasion by viruses, bacteria, and tumors.

Therefore, Glutamine is rightly named a “conditionally essential” Amino acid.

So, if you were wondering why we are always asking some of you if you are including Glutamine in your pre or post workout shake, now you know. It does way more than just ensure carbohydrates are being delivered to the proper places. It is also a key player in maintaining your lean muscle mass (which is what it is primarily known for). However, the real big deal about it is its role in keeping your immune system functioning top notch and avoiding common colds and viruses keeping you healthy and happy!

Recommended amounts can range anywhere from 5-20 grams daily consumed around your workouts. There have been no reported adverse effects from Glutamine supplementation, so, it might be time to add this to your daily intake if you have not already!


Thomas Sampson CFL-3, USAW-2, Sports Nutritionist