JackedPack Blog - Epic Fitness & Nutrition Tips
Ingredients Explained: Glutamine
This is the seventh week of JackedPack’s blog series “Ingredients Explained”. Every week we will highlight a common ingredient found in sports nutrition products.
Glutamine
Glutamine is one of the most popular ingredients and muscle building supplements in the sports nutrition world. This non-essential amino acid has been thoroughly studied in many contexts yet its effectiveness as a standalone recovery supplement is still a bit unclear. There are many claims to the benefits of glutamine supplementation in relation to resistance training. Many bodybuilders and athletes swear by glutamine's effectiveness in promoting recovery, and many believe it does little more than burn a hole in your wallet.
In our own research, we have found a lack of evidence regarding glutamine supplementation’s effectiveness in increasing protein and glycogen synthesis, increasing lean mass, or its positive effect on the exercise-compromised immune system. By no means is this article an exhaustive coverage of glutamine supplementation’s effectiveness in relation to resistance training. There are many tested benefits of glutamine supplementation in other areas of health and bodily function, including: wound healing and recovery from illness, inflammatory bowel disease (IBD) and HIV/AIDS. [1] We are constantly seeking updated information and if you find contrary or supporting evidence or research to what we present here we would love for you to leave links and comments in the comment section below. We are students of the iron and all things that it encompasses so we will be looking for research to prove us wrong.
Glutamine is a non-essential amino acid, meaning that it is synthesized in the human body and not strictly acquired through consumption (essential amino acids can only be supplied through diet). It is the most abundant free amino acid in the body and like many other amino acids, plays a role in protein synthesis and regular brain function. [2] Glutamine is important for removing excess ammonia as well as promoting immune system function. [1] [3] It is found naturally in plant and animal proteins such as beef, pork, poultry, milk, spinach, parsley and cabbage. Following exhaustive exercise, there is a depletion in serum glutamine levels, which has led to the idea that supplementing glutamine may have positive benefits for athletes in muscle recovery and the building and maintaining of lean muscle mass.
In our own research, we have found a lack of evidence regarding glutamine supplementation’s effectiveness in increasing protein and glycogen synthesis, increasing lean mass, or its positive effect on the exercise-compromised immune system. By no means is this article an exhaustive coverage of glutamine supplementation’s effectiveness in relation to resistance training. There are many tested benefits of glutamine supplementation in other areas of health and bodily function, including: wound healing and recovery from illness, inflammatory bowel disease (IBD) and HIV/AIDS. [1] We are constantly seeking updated information and if you find contrary or supporting evidence or research to what we present here we would love for you to leave links and comments in the comment section below. We are students of the iron and all things that it encompasses so we will be looking for research to prove us wrong.
What is Glutamine?
Glutamine is a non-essential amino acid, meaning that it is synthesized in the human body and not strictly acquired through consumption (essential amino acids can only be supplied through diet). It is the most abundant free amino acid in the body and like many other amino acids, plays a role in protein synthesis and regular brain function. [2] Glutamine is important for removing excess ammonia as well as promoting immune system function. [1] [3] It is found naturally in plant and animal proteins such as beef, pork, poultry, milk, spinach, parsley and cabbage. Following exhaustive exercise, there is a depletion in serum glutamine levels, which has led to the idea that supplementing glutamine may have positive benefits for athletes in muscle recovery and the building and maintaining of lean muscle mass.
Benefits of Glutamine Supplementation in Relation To Resistance Training: Popular Claims and Supporting Evidence
POPULAR CLAIM 1: Glutamine supplementation helps increase protein and glycogen synthesis and aids in building lean mass.
CONTRARY EVIDENCE:
*A six-week, double blind study using 31 young adults allocated both placebos and glutamine to test subjects participating in controlled resistance training programs. The conclusion of the study was that “glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults”. [4]
*A study performed at Loughborough University testing the dosing and efficiency of glutamine supplementation in human exercise and sport training found that while some evidence points to the positive effects of glutamine on glycogen synthesis, there is not enough evidence showing the pathways this occurs through or if strict glutamine supplementation is the sole cause [5]
*A study performed at Loughborough University testing the dosing and efficiency of glutamine supplementation in human exercise and sport training found that while some evidence points to the positive effects of glutamine on glycogen synthesis, there is not enough evidence showing the pathways this occurs through or if strict glutamine supplementation is the sole cause [5]
POPULAR CLAIM 2: Glutamine supplementation helps aid in increasing immune function as a counter to exercise-induced immune impairment that leaves athletes susceptible to infection.
CONTRARY EVIDENCE:
*The same study performed at Loughborough University testing the dosing and efficiency of glutamine supplementation in human exercise and sport training found that while it is relatively safe for healthy adults to consume 28g of glutamine daily for up to two weeks, “the suggested reasons for taking glutamine supplements (support for immune system, increased glycogen synthesis, anti-catabolic effect) have received little support from well-controlled scientific studies in healthy, well-nourished humans.” [5]
SUPPORTING EVIDENCE:
*One study testing immune system impairment on athletes following prolonged, exhaustive exercise showed that glutamine supplementation MAY have beneficial effects on the level of subsequent infections. T-helper/T-suppresser cells appeared increased compared to placebos. [6]
POPULAR CLAIM 3: Glutamine is a “conditionally essential” amino acid dude to its role in the body during catabolic states. Therefore, supplementation can help maintain lean muscle during a weight loss programs and prevent catabolism in skeletal muscle.
CONTRARY EVIDENCE:
*A study from the University of Northern Iowa and South Dakota State University tested body composition of healthy college wrestlers participating in weight reduction programs. The conclusion of this study was that there was little benefit or retention of muscle mass with oral glutamine supplementation. It was concluded that more studies are needed on glutamine supplementation to prove its effects regarding retention of lean mass in athletes. [3]
POPULAR CLAIM 4: Glutamine supplementation can increase plasma growth hormone levels.
SUPPORTING EVIDENCE:
*In one study, subjects administered glutamine orally were found to have elevated levels of circulating plasma growth hormone up to 90 minutes following supplementation. [7]
There are many different ways to supplement glutamine. We found that a popular dosage is .1g per kg of body weight within 30 minutes of exercise. This would equate to approximately 9 grams for a 200 lb. athlete.
*In one study, subjects administered glutamine orally were found to have elevated levels of circulating plasma growth hormone up to 90 minutes following supplementation. [7]
How to Use/Dosage Glutamine
There are many different ways to supplement glutamine. We found that a popular dosage is .1g per kg of body weight within 30 minutes of exercise. This would equate to approximately 9 grams for a 200 lb. athlete.
Other manufacturers and producers recommend anywhere from 5-10g daily taken before or after workouts. As with all nutritional supplements, consult with a physician before beginning any supplementation regimen.
Potential Side Effects of Glutamine Supplementation
In healthy adults, there have been no significant side effects shown. Some individuals report an upset stomach when beginning glutamine supplementation or when taking doses above 10g/day. If you choose to supplement your diet with pure glutamine, always error on the side of caution and follow instructions found on product labels.
Conclusion
The purpose of this article is to provide you with information on glutamine supplementation backed by scientific research. We’ve tried to include research that is based solely on pure glutamine supplementation as glutamine is often mixed with amino acid and protein powder matrixes, blends and formulas. Is glutamine effective in regards to recovery and building lean muscle? The studies we've examined don't provide us with enough evidence to make us spend our money on stand-alone glutamine products. Our opinion is that it does not hurt to have it as part of a protein, amino acid or recovery blend. However, paying for a pure glutamine product is probably unnecessary and expensive when you'd be better off spending that money on a more proven recovery product (like BCAAs). Remember, correlation does not imply causation. Many studies of glutamine supplementation’s effectiveness are performed in combination with whey protein, branched-chain amino acids, creatine etc. [8] While some swear by glutamine in certain situations (check out industry leading fitness guru Charles Poliquin’s thoughts on loading glutamine here), there is too much uncertainty for us to drop the extra money on a “high quality” glutamine product.
Are you a glutamine believer or have you seen a study that makes us look stupid? Let us know about it in the comments section below!
[1] “Glutamine”. University of Maryland Medical Center (UMMC). Retrieved from: http://www.umm.edu/altmed/articles/glutamine-000307.htm.
[2] Brosnan JT. “Interorgan amino acid transport and its regulation” J Nutr. 2003 Jun;133(6 Suppl 1):2068S-2072S. Review. PMID: 12771367.
[3] Finn K, Lund R, Rosene-Treadwell M. “Glutamine Supplementation Did Not Benefit Athletes During Short-term Weight Reduction”. J Sports Science and Medicine 2003 Sept-Dec. 2 163-168. Retrieved from: http://www.jssm.org/vol2/n4/7/v2n4-7pdf.pdf.
[4] Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T. “Effect of glutamine supplementation combined with resistance training in young adults”. J Appl Physil 2001 Dec;86(2):142-9. PMID: 11822473.
[5] Gleeson M. “Dosing and efficacy of glutamine supplementation in human exercise and sport training.” J Nutr. 2008 Oct;138(10):2045S-2049S. Review. PMID: 18806122.
[6] Castell LM, Newsholme EA. “The effects of oral glutamine supplementation on athletes after prolonged, exhaustive exercise”. Nutrition 1997 Jul-Aug;13(7-8):738-42. PMID: 9263279.
[7] Welbourne TC. “Increased plasma bicarbonate and growth hormone after an oral glutamine load”. Am J Clin Nutr. 1995 May. Vol. 61 no. 5 1058-1061.
[8] Colker CM, Swain MA, Fabrucini B, Shi Q, Kaiman DS. “Effects of supplemental protein on body composition and muscular strength in healthy athletic male adults”. Current Therapeutic Research 2000 Jan. Vol 61, I 1. P 19-68.
Comments
Posted by Himanshu on Feb 08, 2013
This was so helpful and easy! Do you have any aritecls on rehab?
Posted by Naomi Most on Dec 28, 2012
Dude:
>>> Glutamine is a “conditionally essential” acid dude to its role in the body during catabolic states.
:)
Great article otherwise. I think taking glutamine is a waste of time and money and enjoyment of life, but then, I’m never doing exercise that would qualify as particularly exhaustive.
Maybe there’s some merit to certain pro athletes consuming this supplement, but it seems doubtful there’s much to be gained from glutamine even for most athletes.