It is one of the 20 amino acids found within dietary protein and has been termed “conditionally essential” as it becomes heavily relied on during times of physical trauma and disease. The supplement industry has explored the role it plays in the body and has made exogenous isolated supplementation of this amino acid possible.
Glutamine has been suggested to enhance immunity, contribute to the development of lean mass and aid in gastrointestinal health, but this wouldn’t be an HSCCOACH article without some critical skepticism regarding these claims.
It is not uncommon to see glutamine in many athletes and weight room junkies supplement stacks which is why it makes for such a great topic. With the industry placing more and more attention on supplementation, eager individuals are prepared to spend countless amounts of dough on what seem to be overrated and underpowered products. We hope to clear the air on glutamine and identify where it should stand in your supplement stack.
In immune cells, glutamine is surprisingly used as a form of energy over glucose as it appears to be more readily available at a faster pace contributing to the proliferation of these cells . These immune cells cannot create glutamine, thus it must be retrieved either from the diet or other cells in the body that contain the amino acid. This is likely where the exogenous form of glutamine supplementation came into perspective from an immunology standpoint.
Unfortunately, the fastest rate at which these immune cells can proliferate is found within a normal physiological range of available glutamine. This suggests that extra exogenous provision of glutamine through the form of a supplement is likely useless, unless there is a glutamine deficiency which is unlikely in a healthy, disease lacking population.
Glutamine is found in abundance in many foods which is why a deficiency is rare. In fact, whey and casein proteins which many of you likely take contain a large amount of glutamine per serving. Check the amino acid profile of your protein powder and you will see for yourself.
Overall, the impact glutamine has on the immune system is rather important lending to the formation of immune cells; however, in a population of healthy individuals, the importance of supplementing glutamine on top of a normal balanced diet is more than likely overkill and results in extremely expensive urine.
While amino acids in general play a significant role in the process of muscle protein synthesis, it has been speculated that glutamine is very closely linked with this response. While some in vitro studies have been reported to show a dose response relationship with glutamine and muscle protein synthesis, when looked at in young adults participating in resistance training supplementing with 900 mg/kg/day, no effect was found in muscle performance body composition or protein degradation .
Further, in attempts to see if glutamine adds an additional effect to anabolism, research implementing 300 mg/kg of glutamine into a protein and carbohydrate shake failed to produce a larger anabolic response in healthy adults .
In healthy adults much like those of you who are reading this, there just does not appear to be any compounded anabolic properties of supplemented glutamine in the research currently.
When talking about gastrointestinal health, it is important to understand and incorporate the disorders that can affect optimal GI health. Many healthy individuals experience times of cramps, bloating and even diarrhea around training periods that ultimately could affect their exercise goals.
The mechanism behind GI disorders is thought to be one of which is linked to a decreased amount of blood flow towards the gut due to the blood being shipped towards the working muscle during training. This can lead to nutrient deprivation in the gut and ultimately an individual experiencing poor digestion .
So How Does Glutamine Come Into Play?
Glutamine along with other amino acids are said to have some purpose in terms of positive gut health. In particular, glutamine ingestion is proposed to be an essential fuel source for the small intestine cells that aids in the protection of the cell lining . Through it’s function of strengthening the cell lining of the small intestine, glutamine is said to assist with the inhibition of toxins binding to the cell lining .
Science has shown glutamines clinical use and it has been rectified as an alternative to the reduction of gut disorders in populations such as those with irritable bowel syndrome (Ulcerative Colitis, Pouchitis and Crohn’s) .
Experimental data suggests glutamines importance in reduction in mucosal atrophy and positive GI function in animal studies utilizing rats . However; we cannot be sure that data like this can be extrapolated and even implemented to positive results in healthy humans.
There are claims of numerous human studies on glutamines functionality in improved GI function but most, if not all the research has been conducted on populations that have gastrointestinal disorders.
Yes, incorporating glutamine into your supplement protocol may sound promising and logical as a healthy individual concerned with GI health, but as you dive deeper into the literature there really is insufficient and a lack of robust evidence to support this.
While the exogenous supplementation Glutamine will likely continue to be a part of many supplement stacks in the future, the current research is not robust enough to suggest that it contributes to improved immunity, lean mass and gastrointestinal health in healthy population beyond normal levels.
Further research is needed in healthy individuals to allow us to generalize the effects of this supplement to the majority.
We have left you with a few take home points, and will also leave it to you to decide whether supplementing with Glutamine is efficacious.
Take Home Points:
- Glutamine does have clinical importance in terms of formation of immune cells, but adding it on top of a well balanced diet highlights its irrelevance.
- In terms of glutamine and muscle growth, there is a lack of research suggesting it’s anabolic properties in healthy populations.
- When looking at GI health, the literature reveals glutamines importance in diseased populations but fails to show evidence suggesting its necessity in healthy individuals.
 Ardawi, M. S., & Newsholme, E. A. (1983). Glutamine metabolism in lymphocytes of the rat. Biochemical Journal, 212(3), 835-842. doi:10.1042/bj2120835
 Maclennan, P. A., Smith, K., Weryk, B., Watt, P. W., & Rennie, M. J. (1988). Inhibition of protein breakdown by glutamine in perfused rat skeletal muscle. FEBS Letters, 237(1-2), 133-136. doi:10.1016/0014-5793(88)80186-8
 Maclennan, P. A., Brown, R., & Rennie, M. J. (1987). A positive relationship between protein synthetic rate and intracellular glutamine concentration in perfused rat skeletal muscle. FEBS Letters, 215(1), 187-191. doi:10.1016/0014-5793(87)80139-4
 Zhou, X., & Thompson, J. R. (1997). Regulation of protein turnover by glutamine in heat-shocked skeletal myotubes. Biochimica et Biophysica Acta (BBA) – Molecular Cell Research,1357(2), 234-242. doi:10.1016/s0167-4889(97)00035-9
 Candow, D., Chilibeck, P., Burke, D., Davison, S., & Smith-Palmer, T. (2001). Effect of glutamine supplementation combined with resistance training in young adults. European Journal of Applied Physiology, 86(2), 142-149. doi:10.1007/s00421-001-0523-y
 Wilkinson, S. B., Kim, P. L., Armstrong, D., & Phillips, S. M. (2006). Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise. Applied Physiology, Nutrition, and Metabolism, 31(5), 518-529. doi:10.1139/h06-028
 Ha, E., & Zemel, M. B. (2003). Functional properties of whey, whey components, and essential amino acids: mechanisms underlying health benefits for active people. The Journal of nutritional biochemistry, 14(5), 251-258.
 Tuohy, K. M., Probert, H. M., Smejkal, C. W., & Gibson, G. R. (2003). Using probiotics and prebiotics to improve gut health. Drug discovery today, 8(15), 692-700.
 Duggan, C., Gannon, J., & Walker, W. A. (2002). Protective nutrients and functional foods for the gastrointestinal tract. The American journal of clinical nutrition, 75(5), 789-808.