WHAT IS GLUTAMINE?

When it comes to amino acids, the 3 BCAAs (leucine, isoleucine, and valine) are always in the spotlight. Nowadays, there’s more and more chatter about the benefits of the other amino acids, like (drumroll) – glutamine! Is it time that glutamine steals the show or should it stay as a supporting role?
Let’s find out.

WHAT IS GLUTAMINE?

Glutamine is the most abundant amino acid in the human body [1]. It is a non-essential amino acid, which means that the body can produce it on its own. However, there are certain situations where your body may not be able to produce enough glutamine to meet its needs, such as when the body is in a catabolic state, after intense physical activity, or during times of immense stress. That’s why glutamine is considered “conditionally essential”.

WHAT IS THE ROLE OF GLUTAMINE IN THE BODY?

Glutamine is involved in various metabolic processes in the body. Glutamine plays a role in nitrogen balance, intestinal function, immune health, and acts as a substrate in the metabolism of critical biological compounds (such as nucleotides, glutathione, and neurotransmitters) [1-3]. It’s a proteinogenic amino acid, which means it is a building block of protein and is a major source of energy for cells in the body. [2].

Being the most abundant amino acid in the body, glutamine is primarily found in the muscle and liver. In fact, it’s estimated that up to 80% of the body’s total glutamine content is found in the skeletal muscles [2]. During periods of intense and prolonged exercise, there is a decrease in the glutamine concentrations found in the muscle and plasma [1].

Glutamine is particularly important for cells that divide rapidly, such as cells of the immune system and the gut lining [1]. Glutamine is a primary source of fuel for leukocytes, which means glutamine plays an important role in the immune system [1]. When it comes to the gut, the intestines have a thin layer of epithelial cells that are renewed every 4-5 days. Glutamine plays a role in regulating the cell cycle (especially one with such a high turnover rate), which helps maintain a proper structure and absorptive function of intestinal cells [3].

WHAT ARE SOURCES OF GLUTAMINE?

Glutamine is found in a variety of foods, but has the highest concentration in animal-based sources such as beef, milk, and eggs. It can also be found in some plant-based sources such as corn, white rice, and tofu [2].

You can also find glutamine in many different types of supplements. Because it’s an amino acid, the building blocks of protein, most animal-based protein powders and supplements contain glutamine. To be sure, check the label. You’ll want to see if the product provides the “typical amino acid profile” of the protein (which is not always listed on protein products). This list provides the dose of each individual amino acid, including glutamine.

You can also find glutamine in amino acid supplements. There are amino acid blends that provide several types of amino acids, including glutamine. To be sure, you’ll need to check the label.

If you are looking for a supplement that ONLY provides glutamine, you can find those in the form of pills and powders. Glutamine supplements are typically dosed at a range from 1-5 grams per serving.

It’s also important to be aware of the form, or type, of glutamine. Most supplements use L-glutamine, but there is a glutamine dipeptide that is more rapidly absorbed by the body. On the label, you may see it listed as L-alanyl-L-glutamine. So if you’re looking for a quick glutamine boost, give the dipeptide form a shot.
In conclusion, glutamine is an important amino acid that plays a critical role in various metabolic processes in the body. While the body can produce glutamine on its own, supplementation may be necessary in certain situations, such as during intense physical activity or times of stress.

References
1. Gleeson M. Dosing and efficacy of glutamine supplementation in human exercise and sport training. J Nutr 2008;138:2045S-9S. https://www.sciencedirect.com/science/article/pii/S0022316622096973?via%3Dihub
2. Cruzat, V., Rogero, M. M., Keane, K. N., Curi, R., & Newsholme, P. (2018). Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. Nutrients, 10(11). https://doi.org/10.3390/nu10111564
3. Kim MH, Kim H. The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases. Int J Mol Sci. 2017 May 12;18(5):1051. doi: 10.3390/ijms18051051. PMID: 28498331; PMCID: PMC5454963. https://pubmed.ncbi.nlm.nih.gov/28498331/