Glutamine: The Basics
Glutamine is 1 of 11 nonessential amino acids. Just because it's nonessential doesn't mean it's not necessary. Simply put, the body can produce what it needs. 60% of all free form amino acids come in the form of glutamine. During times of stress (stress not defined), glutamine reserves are depleted.
Glutamine: The Benefits
* Boosts immune system functions
* Maintain muscle mass (preservation)
* Prevents muscle breakdown (catabolism)
* Enhances glycogen storage
* Aids recovery from exercise
* Promotes healing
* Increases growth hormone levels
Many studies have already proven that despite all the hype about how glutamine supplementation might help increase muscle mass, strength and prevent the dreaded OT (overtraining) syndrome, research articles that can be found today (2006) that examine glutamine supplementation benefits on performance, body composition and protein degradation have shown that it offers no noticeable, scientifically proven benefit to the weight lifter.
[There goes that popular theory that glutamine helps preserver your precious muscle after workouts or in general.]
Face it… nobody makes any money proving a supplement doesn't work.
Obviously when I received the original article about glutamine's super muscle building benefits, I was curious myself. After finding the research done by David Barr, I was so excited I couldn't wait to tell you. I'm not going to provide a full reference list – they're all right at the end of David Barr's article which will be included here for your reference.
[Thank you, David Barr, for doing all the leg work so I can pass along your research.]
To summarize some of the key points that David Barr found in his original research:
* A high protein diet or that of a well-fed bodybuilder who is following the standards for protein consumption, will be adequately supplied with all the dietary glutamine they need. About 10% of your total dietary protein intake is comprised of glutamine (3-10% from milk proteins; 15% from mean sources). In my case, given my stats and dietary intake, I'm getting around 29g of glutamine a day from my diet. More than most supplement companies would ever recommend I supplement with anyway.
* A lot of theories hold onto the belief that because glutamine helps with clinical stress, it will help with exercise induced stress. But keep in mind that exercise has nothing on real clinical stress. Nitrogen loss in real clinical stress is vastly more prevalent than the leg workout you just did.
* In a 2001 study by Candow et al, they concluded that 0.9g of supplemental glutamine/kg/day during resistance training had no significant effect on muscle performance, body composition or muscle protein degradation in healthy adults. At my current weight, that is 75g of glutamine a day!
[Re-read this: Candow et al (2001) just blows the presumption that glutamine is somehow an anti-catabolic agent for the bodybuilder and going to preserve all that muscle you are working so hard to keep.]
* Most of the studies on endurance athletes have shown little to no significant benefits in terms of immune system enhancements or functions.
[Dang it! There goes the other popular belief that glutamine is going to enhance your immune system and keep you healthy or recover faster from those stressful workouts.]
"More importantly, there are several studies showing that glutamine supplementation doesn't alter exercise-induced suppression of the immune system! The bottom line is that blood glutamine levels, whether they drop or not following exercise, don't seem to affect immunity to any great extent, which precludes the use of glutamine for this reason." – Hiscock N, Pedersen BK. Exercise-induced immunodepression- plasma glutamine is not the link. J Appl Physiol 2002 Sep;93(3):813-22
* In regards to glutamine's ability to increase the hydration state of cells, Dr. John M Berardi, Ph.D. did some preliminary testing and found that glutamine supplementation has no effect on total body water, intracellular fluid volumes, or extracellular fluid volumes. – Dr. John M Berardi, Ph.D., Appetite For Construction, JohnBerardi.com 2002 Nov 8
* The jury is still out on glutamine enhancing glycogen stores following resistance exercise. Most bodybuilders have a post-workout plan of high glycemic carbs anyway which replace any glycogen lost making further supplement unnecessary.
* In the study by Welbourne (1995) they demonstrated that a small 2g oral dosage of glutamine is capable of significantly elevating alkaline reserves as well as growth hormone. But does this affect the bodybuilder in any measurable way? According to the Cadow et al (2001) they didn't find any lean body mass gains. It might raise your growth hormone significantly but it begs the question…"does it actually DO anything for me when I'm trying to gain muscle?"
[More research is needed in this regard and how glutamine's growth hormone increase affects your muscle.]
* Finally, in regards to protein synthesis (muscle preservation and building) the most current research shows no direct correlation that glutamine increases the rate of protein synthesis at all. Even in some of the worst cases, it has little measurable effect. There goes the muscle building theory!
One study even went as far to test on people, the effects of adding glutamine to an amino acid mixture. They concluded that the original amino acid mixture increased protein synthesis by 48% but adding glutamine to the mixture had no additional protein synthesis effects.
At this point you're probably thinking that glutamine is a worthless supplement.
Am I right?
Glutamine isn't a worthless supplement and my intention is to only show you the other side of the coin so that you can decide for yourself. Even David Barr points out there are instances when glutamine supplementation might be beneficial to the bodybuilder, certain trauma instances, postoperative patient or for total parenteral nutrition (TPN) during severe illness.
* Steroid users improperly coming off a cycle. At this time, testosterone can be very low. There's a risk of increased catabolism regardless of the diet of the bodybuilder. At this point, glutamine supplementation might be beneficial
* When on a cutting diet and trying to get very lean, some bodybuilders will further increase a calorie deficit AND increase exercise volume. This can lead to an increase state of exercise induced stress and catabolism beyond that of a normal bodybuilder on a fat loss regime. Competitive bodybuilders come to mind in this instance. Glutamine may help reduce the stress and exercise related catabolism because it's beyond that of normal exercise induced stress.
* In elite endurance athletes or people who train under extreme conditions several times a day. These are cases where extreme stress (not clinical) but much more intense then regular exercise comes into play and glutamine may be beneficial.
* Under certain circumstances where catabolic waste is extreme (Alcoholism, Chemotherapy side effects, Food allergies, HIV/AIDS, Irritable bowel syndrome, Candida yeast overgrowth, Post-exercise colds and flu, Severe burns Ulcerative colitis). These are situations where a person is injured and trying to prevent catabolic waste.
David Barr makes a final comment after all his research that glutamine isn't a worthwhile supplement to the resistance trainer who is on a proper bodybuilding diet with post workout nutrition. Of course he doesn't call glutamine a dramatic supplement with muscle building benefits. He does show some instances where glutamine might be beneficial in legitimate wasting conditions. It's not exactly a black and white answer.
David said, "Since then I've had a while to let the results sink in. I know that most believers in glutamine will also have a hard time accepting the reality of the situation, which is why I didn't just try to convincingly show that glutamine wasn't as great as everyone thought; I tried to overwhelmingly demonstrate it."