Glutamine is Worthless

[YellowJacket]

TweetEffect of glutamine supplementation combined with resistance training in young adults.

Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T.

College of Kinesiology, University of Saskatchewan, Saskatoon, Canada.

The purpose of this study was to assess the effect of oral glutamine supplementation combined with resistance training in young adults. A group of 31 subjects, aged 18-24 years, were randomly allocated to groups (double blind) to receive either glutamine (0.9 g x kg lean tissue mass(-1) x day(-1); n = 17) or a placebo (0.9 g maltodextrin x kg lean tissue mass(-1) x day(-1); n = 14 during 6 weeks of total body resistance training. Exercises were performed for four to five sets of 6-12 repetitions at intensities ranging from 60% to 90% 1 repetition maximum (1 RM). Before and after training, measurements were taken of 1 RM squat and bench press strength, peak knee extension torque (using an isokinetic dynamometer), lean tissue mass (dual energy X-ray absorptiometry) and muscle protein degradation (urinary 3-methylhistidine by high performance liquid chromatography). Repeated measures ANOVA showed that strength, torque, lean tissue mass and 3-methylhistidine increased with training (P < 0.05), with no significant difference between groups. Both groups increased their 1 RM squat by approximately 30% and 1 RM bench press by approximately 14%. The glutamine group showed increases of 6% for knee extension torque, 2% for lean tissue mass and 41% for urinary levels of 3-methylhistidine. The placebo group increased knee extension torque by 5%, lean tissue mass by 1.7% and 3-methylhistidine by 56%. We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.

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J Strength Cond Res 2002 Feb;16(1):157-60
The effects of high-dose glutamine ingestion on weightlifting performance

Antonio J, Sanders MS, Kalman D, Woodgate D, Street C.

Sports Science Laboratory, University of Delaware, Newark, Delaware 19716, USA.

The purpose of this study was to determine if high-dose glutamine ingestion affected weightlifting performance. In a double-blind, placebo-controlled, crossover study, 6 resistance-trained men (mean +/- SE: age, 21.5 +/- 0.3 years; weight, 76.5 +/- 2.8 kg(-1)) performed weightlifting exercises after the ingestion of glutamine or glycine (0.3 g x kg(-1)) mixed with calorie-free fruit juice or placebo (calorie-free fruit juice only). Each subject underwent each of the 3 treatments in a randomized order. One hour after ingestion, subjects performed 4 total sets of exercise to momentary muscular failure (2 sets of leg presses at 200% of body weight, 2 sets of bench presses at 100% of body weight). There were no differences in the average number of maximal repetitions performed in the leg press or bench press exercises among the 3 groups. These data indicate that the short-term ingestion of glutamine does not enhance weightlifting performance in resistance-trained men.

[YellowJacket]

TweetInt J Sports Med 2000 Jan;21(1):25-30 Related Articles, Links


The effect of free glutamine and peptide ingestion on the rate of muscle glycogen resynthesis in man.

van Hall G, Saris WH, van de Schoor PA, Wagenmakers AJ.

Department of Human Biology, Maastricht University, The Netherlands. RH01769@RH.DK

The present study investigated previous claims that ingestion of glutamine and of protein-carbohydrate mixtures may increase the rate of glycogen resynthesis following intense exercise. Eight trained subjects were studied during 3 h of recovery while consuming one of four drinks in random order. Drinks were ingested in three 500 ml boluses, immediately after exercise and then after 1 and 2 h of recovery. Each bolus of the control drink contained 0.8 g x kg(-1) body weight of glucose. The other drinks contained the same amount of glucose and 0.3 g x kg(-1) body weight of 1) glutamine, 2) a wheat hydrolysate (26% glutamine) and 3) a whey hydrolysate (6.6% glutamine). Plasma glutamine, decreased by approximately 20% during recovery with ingestion of the control drink, no changes with ingestion of the protein hydrolysates drinks, and a 2-fold increase with ingestion of the free glutamine drinks. The rate of glycogen resynthesis was not significantly different in the four tests: 28 +/- 5, 26 +/- 6, 33 +/- 4, and 34 +/- 3 mmol glucosyl units x kg(-1) dry weight muscle x h(-1) for the control, glutamine, wheat- and whey hydrolysate ingestion, respectively. It is concluded that ingestion of a glutamine/carbohydrate mixture does not increase the rate of glycogen resynthesis in muscle. Glycogen resynthesis rates were higher, although not statistically significant, after ingestion of the drink containing the wheat (21 +/- 8%) and whey protein hydrolysate (20 +/- 6%) compared to ingestion of the control and free glutamine drinks, implying that further research is needed on the potential protein effect.

[YellowJacket]

TweetMetabolism 2000 Dec;49(12):1555-60 Related Articles, Links


Intravenous glutamine does not stimulate mixed muscle protein synthesis in healthy young men and women.

Zachwieja JJ, Witt TL, Yarasheski KE.

Exercise and Nutrition Program, Pennington Biomedical Research Center, Baton Rouge, LA, USA.

We investigated the effects of a glutamine-supplemented amino acid mixture on vastus lateralis muscle protein synthesis rate in healthy young men and women. Three men and 3 women (27.8 +/- 2.0 yr, 22.2 +/- 1.0 body mass index [BMI], 56.1 +/- 4.5 kg lean body mass [LBM]) received a 14-hour primed, constant intravenous infusion of L[1-13C]leucine to evaluate the fractional rate of mixed muscle protein synthesis. In addition to tracer administration, a clinically relevant amino acid mixture supplemented with either glutamine or glycine in amounts isonitrogenous to glutamine, was infused. Amino acid mixtures were infused on separate occasions in random order at a rate of 0.04 g/kg/h (glutamine at approximately 0.01 g/kg/h) with at least 2 weeks between treatment. For 2 days before and on the day of an infusion, dietary intake was controlled so that each subject received 1.5 g protein/kg/d. Compared with our previous report in the postabsorptive state, amino acid infusion increased the fractional rate of mixed muscle protein synthesis by 48% (P < .05); however, the addition of glutamine to the amino acid mixture did not further elevate muscle protein synthesis rate (ie, 0.071% +/- 0.008%/h for amino acids + glutamine v 0.060% +/- 0.008%/h for amino acids + glycine; P = .316). Plasma glutamine concentrations were higher (P < .05) during the glutamine-supplemented infusion, but free intramuscular glutamine levels were not increased (P = .363). Both plasma and free intramuscular glycine levels were increased when extra glycine was included in the infused amino acid mixture (both P < .0001). We conclude that intravenous infusion of amino acids increases the fractional rate of mixed muscle protein synthesis, but addition of glutamine to the amino acid mixture does not further stimulate muscle protein synthesis rate in healthy young men and women.

[YellowJacket]

TweetJ Appl Physiol 2002 Sep;93(3):813-22 Related Articles, Links


Exercise-induced immunodepression- plasma glutamine is not the link.

Hiscock N, Pedersen BK.

Copenhagen Muscle Research Centre and Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark.

The amino acid glutamine is known to be important for the function of some immune cells in vitro. It has been proposed that the decrease in plasma glutamine concentration in relation to catabolic conditions, including prolonged, exhaustive exercise, results in a lack of glutamine for these cells and may be responsible for the transient immunodepression commonly observed after acute, exhaustive exercise. It has been unclear, however, whether the magnitude of the observed decrease in plasma glutamine concentration would be great enough to compromise the function of immune cells. In fact, intracellular glutamine concentration may not be compromised when plasma levels are decreased postexercise. In addition, a number of recent intervention studies with glutamine feeding demonstrate that, although the plasma concentration of glutamine is kept constant during and after acute, strenuous exercise, glutamine supplementation does not abolish the postexercise decrease in in vitro cellular immunity, including low lymphocyte number, impaired lymphocyte proliferation, impaired natural killer and lymphokine-activated killer cell activity, as well as low production rate and concentration of salivary IgA. It is concluded that, although the glutamine hypothesis may explain immunodepression related to other stressful conditions such as trauma and burn, plasma glutamine concentration is not likely to play a mechanistic role in exercise-induced immunodepression.

[YellowJacket]

TweetEffect of glutamine and protein supplementation on exercise-induced decreases in salivary IgA.

Krzywkowski K, Petersen EW, Ostrowski K, Link-Amster H, Boza J, Halkjaer-Kristensen J, Pedersen BK.

The Copenhagen Muscle Research Centre, Rigshospitalet, 2200 Copenhagen, Denmark.

Postexercise immune impairment has been linked to exercise-induced decrease in plasma glutamine concentration. This study examined the possibility of abolishing the exercise-induced decrease in salivary IgA through glutamine supplementation during and after intense exercise. Eleven athletes performed cycle ergometer exercise for 2 h at 75% of maximal oxygen uptake on 3 separate days. Glutamine (a total of 17.5 g), protein (a total of 68.5 g/6.2 g protein-bound glutamine), and placebo supplements were given during and up to 2 h after exercise. Unstimulated, timed saliva samples were obtained before exercise and 20 min, 140 min, 4 h, and 22 h postexercise. The exercise protocol induced a decrease in salivary IgA (IgA concentration, IgA output, and IgA relative to total protein). The plasma concentration of glutamine was decreased by 15% 2 h postexercise in the placebo group, whereas this decline was abolished by both glutamine and protein supplements.None of the supplements, however, was able to abolish the decline in salivary IgA. This study does not support that postexercise decrease in salivary IgA is related to plasma glutamine concentrations.

[YellowJacket]

TweetEffect of carb intake on plasma glutamine

Int J Sport Nutr 1998 Mar;8(1):49-59 Related Articles, Links


Effect of low- and high-carbohydrate diets on the plasma glutamine and circulating leukocyte responses to exercise.

Gleeson M, Blannin AK, Walsh NP, Bishop NC, Clark AM.

School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, England.

We examined the effects of a low-carbohydrate (CHO) diet on the plasma glutamine and circulating leukocyte responses to prolonged strenuous exercise. Twelve untrained male subjects cycled for 60 min at 70% of maximal oxygen uptake on two separate occasions, 3 days apart. All subjects performed the first exercise task after a normal diet; they completed the second exercise task after 3 days on either a high-CHO diet (75 +/- 8% CHO, n = 6) or a low-CHO diet (7 +/- 4% CHO, n = 6). The low-CHO diet was associated with a larger rise in plasma cortisol during exercise, a greater fall in the plasma glutamine concentration during recovery, and a larger neutrophilia during the postexercise period. Exercise on the high-CHO diet did not affect levels of plasma glutamine and circulating leukocytes. We conclude that CHO availability can influence the plasma glutamine and circulating leukocyte responses during recovery from intense prolonged exercise.

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Clin Nutr 2002 Oct;21(5):423-9 Related Articles, Links


Carbohydrate supplementation during intense exercise and the immune response of cyclists.

Bacurau RF, Bassit RA, Sawada L, Navarro F, Martins E Jr, Costa Rosa LF.

Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.

OBJECTIVE: To evaluate the effect of carbohydrate supplementation upon some aspects of the immune function in athletes during intense indoor cycling. METHODS: Twelve male athletes cycled for 20 min at a velocity corresponding to 90% of that obtained at the anaerobic threshold and rested for 20 min. This protocol was repeated six times. The athletes received, during the trial, water ad libitum, or a solution of carbohydrate (95% glucose polymers and 5% fructose) at 10% (w/v), 1 g kg h every 20 min, starting at the 10th minute of the first exercise period, plus extra water ad libitum. RESULTS: Exercise induced a reduction in peripheral blood mononuclear cell proliferation (37%) as well as in the production of cytokines by cultured cells (interleukin-1 (IL-1), interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), by 37%, 35%, 26% and 16%, respectively). All of these changes were prevented by the ingestion of a carbohydrate drink by the athletes, except that in IFN-gamma production, which was equally decreased (17%) after the second trial. The concentration of plasma glutamine, an important fuel for immune cells, was decreased in the placebo group but maintained in the group that received carbohydrate. CONCLUSION: Carbohydrate supplementation affects positively the immune response of cyclists by avoiding or minimizing changes in plasma glutamine concentration


An excerpt from "Appetite For Construction
Building Results From Research"
by John M. Berardi

Should I Spend my Hard-Earned Money on Glutamine or Hookers?

.... A high protein diet provides a big whack of glutamine as it is. In fact, if you follow standard bodybuilding protein recommendations, about 10% of your total dietary protein intake is composed of glutamine (milk proteins are composed of somewhere between 3 — 10% glutamine while meat is composed of about 15% glutamine). This means that a high protein diet (400g/day) already provides me with about 40g of glutamine.

• While the theorists still cling to the idea that since glutamine helps clinical stress, it might help with exercise stress, it‚s important to note that exercise stress has got nothin‚ on surgery, cancer, sepsis, burns, etc. For example, when compared with downhill running or weight lifting, urinary nitrogen loss is 15x (1400%) greater in minor surgery, 25x (2400%) greater in major surgery, and 33x (3200%) greater in sepsis. When it comes to the immune response, it‚s about 9x (800%) greater with surgery. When it comes to metabolic increase, it‚s 7x (600%) greater with burn injury, and when it comes to creatine kinase release; it‚s about 2x (100%) greater with surgery. As I said, exercise has got nothin‚ on real, clinical stress. It‚s like trying to compare the damage inflicted by a peashooter and that inflicted by a rocket launcher.

• The major studies examining glutamine supplementation in otherwise healthy weightlifters have shown no effect. In the study by Candow et al (2001), 0.9g of supplemental glutamine/kg/day had no impact on muscle performance, body composition, and protein degradation. Folks, that's 90g per day for some lifters.

• The majority of the studies using glutamine supplementation in endurance athletes have shown little to no measurable benefit on performance or immune function.

• And with respect to glycogen replenishment in endurance athletes, it's interesting to note that the first study that looked at glycogen resynthesis using glutamine missed a couple of things. Basically, the study showed that after a few glycogen depleting hours of cycling at a high percentage of VO2 max interspersed with very intense cycle sprints that were supramaximal, a drink containing 8g of glutamine replenished glycogen to the same extent as a drink containing 61g of carbohydrate.

The problem was that during the recovery period, a constant IV infusion of labeled glucose was given (i.e., a little bit of glucose was given to both groups by IV infusion). While this isn't too big of a deal on its own since the infusion only provided a couple of grams of glucose, the other problem is that during glycogen depleting exercise, a lot of alanine, lactate, and other gluconeogenic precursors are released from the muscle.

What this means is that there's a good amount of glucose that will be formed after such exercise, glucose that will be made in the liver from the gluconeogenic precursors and that will travel to the muscle to replenish glycogen. Therefore, without a placebo group that receives no calories, carbohydrates, or glutamine, we have no idea of knowing whether or not the placebo would have generated the same amount of glycogen replenishment as the glutamine group or the glutamine plus carbohydrate group. To say it another way, perhaps there's a normal glycogen replenishment curve that was unaffected by any of the treatments.

• And finally, with respect to the claims that glutamine might increase cell swelling/volume (something I once believed was a reality), we decided to test this theory out in our lab using multifrequency bioelectric impedance analysis as well as magnetic resonance spectroscopy. The pilot data that's kicking around has demonstrated that glutamine supplementation has no effect on total body water, intracellular fluid volumes, or extracellular fluid volumes (as measured by mBIA) and has no effect on muscle volume (as measured by nMRS)...

[YellowJacket]

Tweet**Ive got plenty more if anyone still thinks this shit is beneficial

And before you come in and say "it works for me, I recover faster with it and I wasnt as sick for as long...blah blah blah" Think about the physiological processes that take place for all of that to happen and go back and read these articles, not gonna happen. Oh the power of placebo.

[OldWiseGuy]

TweetNot all studies are correct. And it's still a protein. Do you wish to say that protein is worthless?

[OldWiseGuy]

TweetDo you know how to read yellowjacket? It did add a small bit to performance. But everyone knows it's about recovery. And malt is not a true placebo and has a effect of it's own.

[PIT]

TweetDidn't do jack shit for me.

PIT

[YellowJacket]

Tweet

Originally posted by OldWiseGuy
Not all studies are correct. And it's still a protein. Do you wish to say that protein is worthless?

Actually its an amino acid. Do you understand the compounds and their links? So maybe before you attempt to be a smartass you should educate yourself a bit. Protein is a strand of amino acids, glutamine is a single amino acid that the body produces in abundance. Seemed like a good argument on your part huh? Oh well.

Do you know how to read yellowjacket? It did add a small bit to performance. But everyone knows it's about recovery. And malt is not a true placebo and has a effect of it's own.

Now you can make this personal if you wish, but I think you should reconsider. Yes, I know how to read, are the words to big for you to interpret? Obviously since you're still rambling on about its benefits.

[YellowJacket]

TweetHere, this one is pretty easy to read

Glutamine
Destroying the Dogma, Part 1
by David J. Barr


One of the most frequent supplement questions I get as a strength coach is whether or not athletes should use the amino acid glutamine for either performance enhancement or size gains.

The topic comes up so much that it almost seems as though glutamine is a "no brainer" supplement just like creatine. In fact, its popularity is such that at least two separate online message boards, as well as numerous magazines, have feature articles on the use of glutamine as a supplement. The dogma of glutamine supplementation had even permeated the SWIS symposium to the extent that the numerous conversations about this amino acid were solely about how much to take, rather than whether or not to take it.

So, it seems as though everything is pretty cut and dried when it comes to glutamine use… or is it? While there was some literature-supported speculation as to the potential benefits of glutamine supplementation, there needs to be an updated review of the literature examining the current status of this purported "wonder supplement." In fact, there's quite a bit of information that's been left out of the popular bodybuilding literature that needs to be brought to light.

But before we get on to that, we should review some of the basics of glutamine.


Glutamine: The Basics

For those of you who are new to the concept of glutamine supplementation, you should know that it's a non-essential amino acid created largely by our muscles. It's also noteworthy that glutamine is the most abundant free amino acid in our bodies, comprising up to 2/3 of the muscle free amino acid pool.(13) This fact, coupled with the idea that muscle is the largest producer of this amino acid, could suggest that supplementation would be beneficial.

One potential problem with this is that glutamine is a non-essential amino acid (meaning that we don't have to consume outside sources containing this amino acid because our bodies can make it on its own), but this is where things get interesting: the use of glutamine by many different cells in our bodies is so great that there may be times when its use exceeds its availability, therefore glutamine has been termed a "conditionally essential" amino acid.(18)

This means that during times of physical stress the body may actually need glutamine from the diet to maintain proper cellular function. Clearly, activities such as resistance training constitute a physical stress on the body, which is one reason that athletes have been targeted for glutamine supplementation.

Another interesting fact about our muscles and glutamine is the issue of transport. For an amino acid to get into or out of our muscles, it has to be transported by specific carriers. Using these carriers, our muscle takes up amino acids according to demand from protein composition (i.e. what our muscles need the most), BUT amino acid release is NOT according to composition.

Alanine and glutamine can account for up to 50% of amino acid release from muscle despite accounting for only about 15% of total muscle protein.(31) Obviously, this is a huge discrepancy—which is normally made up for through glutamine production—but as mentioned earlier, during times of physical stress (i.e. exercise), the synthesis of glutamine is hindered. Everyone knows that lacking even one amino acid can hinder muscle growth, which fortifies the theory of glutamine supplementation by athletes.

Now that you're familiar with the basics behind glutamine supplementation, it's time to delve into the literature and pull out some more specific theories as to the beneficial effects of glutamine supplementation.


Glutamine and Muscle Mass

Interest first arose in glutamine as a supplement when it was found that glutamine enrichment elevated levels of protein synthesis in isolated rat muscles.(21) This isn't surprising since it's also been found that muscle protein synthesis levels can be correlated with free glutamine levels.(17) It's also been shown in vitro using rat skeletal muscle cells that glutamine may decrease protein breakdown.(22)

Additionally, we know that the anabolic/catabolic state of a muscle cell is related to it's hydration status—this simply means that cellular swelling has an anabolic or an anticatabolic effect on the affected cells (including muscle cells). Based on this, it's been found that glutamine supplementation may mediate cell swelling and therefore an anticatabolic effect through either increasing cell swelling or hindering cellular dehydration.(28)

Sure you say, these theories are all well and good in cell cultures or animals, but what about the human studies? Well, studies in humans indicate that glutamine supplementation may improve nitrogen balance in critically ill patients, as well as assist in the prevention of protein synthesis decreases following surgery (a HUGE physical stress) or following a 14-hour fast.(13, 12,24,13) There have even been a couple of studies done on resistance trained subjects (more on that a little later)!


Glutamine and Overtraining

We've all felt the scourge of overtraining: the lethargy, the sickness, and the lack of desire to train. Aside from the horrible feeling associated with overtraining, we also know that the longer we're out of the gym, the longer we go without any anabolic stimulus to our muscles. Based on this, another theory suggesting glutamine supplementation for athletes involves the prevention of overtraining.

Glutamine is used as a fuel source by many cells of our body, including many cells of our immune system. Now if you recall that there are times of stress where the body's production fails to meet its needs for glutamine, you can see that this could negatively affect the immune system. In fact, you may not be surprised to find that blood glutamine levels may be compromised following exercise induced overtraining.(1)

Surveys of endurance athletes supplementing with glutamine following a marathon race showed lower rates of infection than those who didn't supplement.(8,9) As for the applicability to bodybuilding, one study showed that resistance exercise may induce a small transient (ie short-term) negative effect on some cells of the immune system, although plasma glutamine levels weren't examined.(6)

So now we have theories for glutamine supplementation to increase protein synthesis/inhibit protein breakdown, as well as boost immunity following intense exercise. This sounds great, but we have yet to look at glutamine's potential effect to stimulate glycogen replenishment following exercise. Glutamine infusion has been shown to enhance glycogen stores following cycling exercise twice as much as compared to subjects who infused saline or other amino acids.(27) If this happened after weight training, it could even help with our cellular swelling and have the aforementioned postive effect on protein accretion.

Another study supports the use of glutamine for enhancing muscle glycogen. Bowtell et al. found that glutamine supplementation following exercise enhanced glycogen resynthesis in muscle just as well as the ingestion of a glucose polymer.(4)

Sadly at this point, many readers have already gone out and bought their kilos of glutamine, and are now reading only to find out how to use the stuff. You may argue, why not? There's plenty of evidence to support the theories presented! This was exactly the thinking when glutamine was introduced to bodybuilders several years ago. In fact, the journal articles reviewed above are the same research papers that can be found time and again, in any outdated article that's trying to sell you on glutamine. But things have recently changed; new studies have been done on animals, and people involved in resistance training, but the results are less than positive.


What the Glutamine Salespeople Don't Want You To Know:

Glutamine and Protein Synthesis — The other side of the coin

We've seen the theory that glutamine levels in the blood and muscle may decrease during or following exercise, and that this decrease correlates with reduced levels of protein synthesis. Several studies have addressed whether this relationship between glutamine and protein synthesis was a coincidental or a causal (meaning that one caused the other) relationship.

The first study compared the abilities of glutamine and the amino acid alanine to stimulate protein synthesis in rats with artificially reduced blood and muscle glutamine levels.(23) As expected, glutamine infusion increased intramuscular glutamine levels, while alanine didn't. Surprisingly, even depleting muscle glutamine levels by 60% had no effect on protein synthesis. What may also surprise you is that restoring blood and muscle glutamine levels to normal had no effect on protein synthesis compared to rats receiving no glutamine treatment! Additionally, even though whole body protein turnover didn't change, alanine stimulated protein synthesis!

In support of this contention, researchers studied the effect of glutamine supplementation on septic rats. Sepsis is a severely catabolic condition, during which glutamine levels (and protein synthesis) fall. Again, this study showed that despite increasing muscle glutamine levels to even higher than normal, it had no effect on protein synthesis or the catabolic state of the rats.(11)

Cumulatively, these studies show that decreased or increased levels of glutamine in the muscle has no effect on protein synthesis.

Another study, performed on people, examined the effect of adding glutamine to an amino acid mixture on muscle protein synthesis .(30) Ultimately, infusion of the original amino acid mixture increased protein synthesis by nearly 50%, but adding glutamine to this mix had no additional effect. This study is particularly relevant because most consumers of glutamine do so following a workout, along with other amino acids (or a whole protein).

Finally, Wusteman et al., used a drug to reduce muscle protein synthesis, along with muscle glutamine levels, in rats.(29) Much like the Olde Damink et al. study, restoring muscle glutamine levels to normal had no effect on protein synthesis. This study further supports the concept that blood and muscle glutamine levels have no bearing on protein synthesis and protein turnover.


Editor's note: Part 2, which pretty much presents a case for relegating glutamine to the Retired Supplements shelf (except for very specific circumstances) will be posted next week.


David J. Barr, CSCS, MSc. Candidate, is a Varsity Strength and Conditioning Coach at the University of Waterloo

[YellowJacket]

TweetHeres part 2 for you, and my my my, look at all those references

Last week, David Barr started shooting holes into the reputation of the long-standing bodybuilding supplement, glutamine.. While glutamine was staggered and bleeding at the end of part 1, watch as Barr sticks a sharp knife into glutamine's still barely beating heart and twists it.


Another One Bites the Dust

You may recall that the theory of exercise induced immunosuppression is often cited, based on the fact that glutamine levels decrease after exercise, as does our immunity.(10)

What we must now address is whether the relationship between the body’s glutamine stores and the effects of exercise on the immune system exhibit a causal or coincidental relationship (just as we did for protein synthesis). A recent review article in "The Journal of Applied Physiology" examined this connection between plasma glutamine and exercise-induced immunosuppression.(15)

The study admitted that there are conflicting reports about plasma glutamine levels following long duration exercise, repeated high intensity bouts, as well as short single high intensity bouts. This indicates that plasma glutamine concentrations may be affected differently depending on the intensity and duration of exercise.

Even data on blood glutamine concentrations following eccentric exercise is mixed, which can relate directly to bodybuilders and their use of heavy loads. Based on the relatively small reductions in plasma glutamine that might occur following exercise, supplementation with glutamine wouldn’t likely affect the immune cells.

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.

Another recent review looked at over 75 research papers pertaining to the effect of glutamine on immunity and muscle growth, and came to the following conclusion: "Overall, although glutamine obviously plays important metabolic roles within the body, supplementation does not appear to provide consistent beneficial or therapeutic effects, except during certain catabolic situations. Glutamine availability, therefore, does not seem to be a limitation in many challenge situations."(19)


What about the glycogen?!

Yep, we have one final theory to validate spending God-awful amounts of money on glutamine; that of enhanced glycogen resynthesis following our workouts. In addition to the aforementioned studies showing better glycogen storage, there is also a study showing no effect of oral glutamine on glycogen regeneration following high intensity interval training.(26)

This issue was actually addressed by the authors of the Candow study, who found no strength or mass changes in trained individuals using glutamine (versus a placebo).(7) They suggested that the studies done showing enhanced glycogen recovery used exercise bouts which depleted intramuscular glycogen by 90%(!), while resistance exercise only depletes muscular glycogen by ~36%.

The bottom line is that the jury is still out on glutamine enhancing glycogen resynthesis following resistance exercise, but it seems unlikely that it would have any effect. Toss in the huge amounts of high glycemic carbs that most of us use following our workouts, and it’s almost a sure bet that glutamine won’t do anything for additional glycogen storage under normal dietary situations.


Things That Mom Never Told You About Glutamine Supplementation

It’s important to examine the method used for getting glutamine into the body in the human studies presented. Unfortunately, getting glutamine into our blood and to our muscles is a lot harder than one may expect. It was mentioned earlier that many cells of the body use glutamine for fuel. Well one area of cells that just loves glutamine is the gastrointestinal tract. In fact, it can account for up to 40% of glutamine utilization in the body! Now figure out the first area to come into contact with our "wonder supplement," and you can see that you have to take a whole crap-load of the stuff all at once, just so our gut doesn’t use it all!

Now, dumping 20g of one amino acid into our bodies at once may sound fun to some, but then again we can safely call these people masochists. For the rest of us, this huge glutamine dump may lead to some GI distress, which we all know is NOT fun.

Fortunately, the two studies performed with bodybuilders using relatively high dosages of glutamine (0.3g/kg/d and 0.9g/kg lean mass/d) reported no side effects of any kind.(2, 7) What is unfortunate is that the authors of these studies also showed no positive effect of any kind!


Glutamine and Resistance Trained Athletes: The Studies

One recent study examined the effect of acute glutamine ingestion on weightlifting performance.(2) This study examined the potential buffering effect of glutamine on lactic acid production during resistance exercise (to the point of momentary muscular failure).

One hour following glutamine ingestion (0.3g/kg), glycine ingestion (0.3g/kg), or placebo drink ingestion, the trained subjects performed 2 sets each of leg press (@ 200% body weight) and bench press (@ 100% body weight). This would equate to an average of ~23g of either amino acid ingested all at once, but there were no reports of GI discomfort.

Each subject consumed one of the three supplements before three separate testing sessions separated by a week. There was no effect of glutamine on number of reps performed compared to glycine or placebo ingestion. These results indicate that a high dose of glutamine ingested before exercise has no positive or negative effects on weightlifting performance in trained subjects.

If you’re interested in glutamine for its effect on muscle mass and strength, you’re in luck because a study was done on that, too! This next study is undoubtedly one of the best kept secrets in bodybuilding! In this study, the trained subjects consumed either 0.9g/kg lean body mass/day (average of 45g/day!), or a placebo, in 2 divided doses.(7)

It's noteworthy that using this amount of glutamine would run over 1200$USD per year for a 200lb guy!

By the end of the 6-week period, there were no differences in terms of 1Rep Max on squat or bench between the groups. There were also no differences between groups when it came to the gains in lean body mass (i.e. the amount of muscle they put on) during the trial period. This study was well designed and used the highest amount of glutamine ever studied for these purposes.


Glutamine Ain't All That Bad

After kicking the crap out of glutamine for most bodybuilding purposes, it is important to realize that there are certain situations where glutamine can be useful.

A recent study from the journal "Metabolism" shows that glutamine injections following glucocorticoid (ie catabolic steroid -such as cortisol) treatment can increase protein synthesis in the gastrointestinal system of dogs.(16) Unfortunately, nonoxidative leucine disposal, a measure of whole-body protein synthesis, remained unchanged in the glutamine treated group.

There are a dozen ways you could interpret these findings, but at least we can say that glutamine supplementation may improve protein synthesis in some tissues following gluccocorticoid treatment. In fact, glucocorticoid treatment is one area where glutamine supplementation may really help!

Another study with rats supports this contention, again using corticosteroid administration.(14) Although glutamine infusion had no effect on muscle protein synthesis in the rats not receiving cortisol, there was a beneficial effect in the glucocorticoid treated rats. In fact, glutamine infusion actually attenuated more than 70% of the muscle wasting caused by the cortisol injections!

Along these lines, certain catabolic conditions (such as sepsis) may be another useful situation in which glutamine could help out. One literature review clearly concluded that "The increased intake of glutamine has resulted in lower septic morbidity in certain critically ill patient populations."(3) This means that people with certain catabolic medical conditions may live longer when taking glutamine. Keeping this in mind, we also know that AIDS can be associated with muscle wasting. Recent evidence has arisen to demonstrate that glutamine supplementation may attenuate AIDS-induced muscle wasting.(25)

Overall, these studies show that glutamine could be very helpful for muscle mass during corticosteroid treatment and certain wasting conditions. For those of you who think that your everyday training may be intense enough to simulate a catabolic condition, keep in mind that these people are dying because of their catabolism, so you're really no where near that level.

The only time a bodybuilder even remotely approaches these kind of catabolic conditions is when improperly coming off a cycle of anabolic steroids. In this situation the user has minimal anabolic stimulus from Testosterone and a large amount of cortisol just waiting to eat that muscle (again, this is only when done improperly). In this situation, glutamine supplementation might help, but it's not a situation you should be in anyway.

The other time that glutamine supplementation may be beneficial to bodybuilders is when on a low carbohydrate diet. Glutamine can not only be converted to glucose, but may also have an anapleurotic effect.(5) In other words, it may replenish metabolic intermediates, in this case, ATP (especially important when you're lacking carbs). This is another article unto itself, so I'll leave it at that for now.

You may be asking why you’ve never heard of most of these studies, and why everything you’ve heard about glutamine was always so amazing. I can indirectly answer that by reminding you of one simple fact: no one makes money by showing that supplements don’t work. I’ll leave the rest of the thinking on this matter to you.

Despite this, you may still be skeptical regarding the points mentioned, based on the original dogmatic theories associated with glutamine use (and how long you’ve been hit over the head with them). But then again, that’s why they’re just theories. To paraphrase Homer Simpson: "Sure it may work in theory, but then again even communism works...in theory."

It's the mark of a great person who can devise a theory, drawing from many different ideas, and stick to it. Without this, science would be meaningless. But it's the mark of an even greater person when they can admit, without shame, that their idea is wrong.

Sometimes theories pan out and sometimes they don’t, but we have to be able to let go of them once they're shown to be incorrect. This doesn’t mean that we shouldn’t believe new theories when they first come out; it just means that we have to be conscious about the fact that they aren’t dogma and may be wrong.

Case in point: The theory behind glutamine was so great that I refused to believe the authors of the Candow et al. (2001) study when they told me the results in person. I was an educated bodybuilder and I wasn’t going to let some egghead scientist (who was actually more muscular than I was, and therefore far from being just an "egghead") tell me that I was wrong. Of course, I wanted to believe that glutamine was useful (even though I got nothing from it) and when someone wants to believe something you can’t convince them otherwise.

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.


Bottom Line

Glutamine is good for hospital patients and rich people with money to waste. If you’re involved in resistance training and already have proper post workout nutrition, along with a moderate carb intake, then glutamine probably won’t do anything for you. In fact, none of the proposed theories dealing with glutamine supplementation have worked out in the athletic world. It’s also one of the most expensive supplements around (simply based on dosage recommendations), so it’s way too costly to use for personal experimentation — especially when the updated scientific literature doesn’t support the theories.


David J. Barr, CSCS, MSc. Candidate, is a Varsity Strength and Conditioning Coach at the University of Waterloo. You can contact him at dbmuscle@hotmail.com.


References

1. Antonio J, Street C.

Glutamine: a potentially useful supplement for athletes. Can J Appl Physiol 1999 Feb;24(1):1-14

2. Antonio J, Sanders MS, Kalman D, Woodgate D, Street C.

The effects of high-dose glutamine ingestion on weightlifting performance. J Strength Cond Res 2002 Feb;16(1):157-60

3. Boelens PG, Nijveldt RJ, Houdijk AP, Meijer S, van Leeuwen PA.

Glutamine alimentation in catabolic state. J Nutr 2001 Sep;131(9 Suppl):2569S-77S; discussion 2590S

4. Bowtell JL, Gelly K, Jackman ML, Patel A, Simeoni M, Rennie MJ.

Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. J Appl Physiol 1999 Jun;86(6):1770-7

5. Bruce M, Constantin-Teodosiu D, Greenhaff PL, Boobis LH, Williams C, Bowtell JL.

Glutamine supplementation promotes anaplerosis but not oxidative energy delivery in human skeletal muscle. Am J Physiol Endocrinol Metab 2001 Apr;280(4):E669-75

6. Bush JA, Dohi K, Mastro AM, Volek J, Lynch JM, Triplett-McBride, Putukian M, Sebastianelli WJ, Newton RU, Hakkinen K, Kraemer WJ. Exercise and recovery responses of lymphokines to heavy resistance exercise J Str Cond Res 2000 14(3) 344-349

7. Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T.

Effect of glutamine supplementation combined with resistance training in young adults. Eur J Appl Physiol 2001 Dec;86(2):142-9

8. Castell LM, Poortmans JR, Newsholme EA.

Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol Occup Physiol 1996;73(5):488-90

9. 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

10. Castell LM.

Can glutamine modify the apparent immunodepression observed after prolonged, exhaustive exercise? Nutrition 2002 May;18(5):371-5

11. Fang CH, James JH, Fischer JE, Hasselgren PO.

Is muscle protein turnover regulated by intracellular glutamine during sepsis? JPEN J Parenter Enteral Nutr 1995 Jul-Aug;19(4):279-85

12. Hammarqvist F, Wernerman J, von der Decken A, Vinnars E.

Alanyl-glutamine counteracts the depletion of free glutamine and the postoperative decline in protein synthesis in skeletal muscle. Ann Surg 1990 Nov;212(5):637-44

13. Hankard RG, Haymond MW, Darmaun D.

Effect of glutamine on leucine metabolism in humans. Am J Physiol 1996 Oct;271(4 Pt 1):E748-54

14. Hickson RC, Czerwinski SM, Wegrzyn LE.

Glutamine prevents downregulation of myosin heavy chain synthesis and muscle atrophy from glucocorticoids. Am J Physiol 1995 Apr;268(4 Pt 1):E730-4

15. Hiscock N, Pedersen BK.

Exercise-induced immunodepression- plasma glutamine is not the link. J Appl Physiol 2002 Sep;93(3):813-22

16. Humbert B, Nguyen P, Dumon H, Deschamps JY, Darmaun D.

Does enteral glutamine modulate whole-body leucine kinetics in hypercatabolic dogs in a fed state? Metabolism 2002 May;51(5):628-35

17. Jepson MM, Bates PC, Broadbent P, Pell JM, Millward DJ.

Relationship between glutamine concentration and protein synthesis in rat skeletal muscle. Am J Physiol 1988 Aug;255(2 Pt 1):E166-72

18. Lacey JM, Wilmore DW.

Is glutamine a conditionally essential amino acid? Nutr Rev 1990 Aug;48(8):297-309

19. Lobley GE, Hoskin SO, McNeil CJ.

Glutamine in animal science and production. J Nutr 2001 Sep;131(9 Suppl):2525S-31S; discussion 2532S-4S

20. Low SY, Taylor PM, Rennie MJ.

Responses of glutamine transport in cultured rat skeletal muscle to osmotically induced changes in cell volume. J Physiol 1996 May 1;492 ( Pt 3):877-85

21. MacLennan PA, Brown RA, Rennie MJ.

A positive relationship between protein synthetic rate and intracellular glutamine concentration in perfused rat skeletal muscle. FEBS Lett 1987 May 4;215(1):187-91

22. MacLennan PA, Smith K, Weryk B, Watt PW, Rennie MJ.

Inhibition of protein breakdown by glutamine in perfused rat skeletal muscle. FEBS Lett 1988 Sep 12;237(1-2):133-6

23. Olde Damink SW, de Blaauw I, Deutz NE, Soeters PB.

Effects in vivo of decreased plasma and intracellular muscle glutamine concentration on whole-body and hindquarter protein kinetics in rats. Clin Sci (Lond) 1999 Jun;96(6):639-46

24. Petersson B, von der Decken A, Vinnars E, Wernerman J.

Long-term effects of postoperative total parenteral nutrition supplemented with glycylglutamine on subjective fatigue and muscle protein synthesis. Br J Surg 1994 Oct;81(10):1520-3

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[iced]

Tweetive always thought it was placebo. I read that same article in T-mag. nice read. That crap is way too expensive.

[Alpine]

Tweet

Originally posted by YellowJacket


Overall, these studies show that glutamine could be very helpful for muscle mass during corticosteroid treatment and certain wasting conditions. For those of you who think that your everyday training may be intense enough to simulate a catabolic condition, keep in mind that these people are dying because of their catabolism, so you're really no where near that level.

The only time a bodybuilder even remotely approaches these kind of catabolic conditions is when improperly coming off a cycle of anabolic steroids. In this situation the user has minimal anabolic stimulus from Testosterone and a large amount of cortisol just waiting to eat that muscle (again, this is only when done improperly). In this situation, glutamine supplementation might help, but it's not a situation you should be in anyway.

The other time that glutamine supplementation may be beneficial to bodybuilders is when on a low carbohydrate diet. Glutamine can not only be converted to glucose, but may also have an anapleurotic effect.(5) In other words, it may replenish metabolic intermediates, in this case, ATP (especially important when you're lacking carbs). This is another article unto itself, so I'll leave it at that for now.

So I guess this is what the great Glutamine has been reduced to. A slight help in extremely catabolic conditions. Well, I have 600grams of L-Glutamine left still. I guess I might as well take it post cycle - cant hurt. I'll never buy it again though.