Is supplementing with Glutamine beneficial to exercise performance?

Question

What benefits, if any, does Glutamine have on an experienced athlete? Given that the athlete has a balanced diet.

In past research, mostly based on examine.com, I have come to the conclusion that Glutamine does not have any significant benefits on exercise performance on an individual. Given that this individual is an experienced, healthy athlete who has a balanced diet.

Examine.com's Glutamine Article

Recently though I was told thought that this is not true. The person that told me I was incorrect was basing his argument on information he had read in a textbook on nutrition. I have never been able to get a completely confident answer. That being said, I am looking for answers that are backed by scientific information and verified and unbiased sources. Meaning, I am not looking for the first article on Glutamine from bodybuilding.com.

Answer 1

You aren't going to get more authoritative answers than what you already researched. Glutamine's response has several studies, and the quality of the studies have been graded (A-D) and magnitude of response for humans have been given a 3 star rating. Each of the studies are available in a link on the last column.

The bottom line is that for humans, there is "Minor" good affects for recovery and reduction of DOMS post training. There is a noticeable affect, however

There may be rat studies that show much better response to glutamine, but Examine.com does not consider those.

The questions I have are:

• What studies did this book on nutrition use?
• Who was the author?
• What was the context of the book?

These are all relevant to your friend's position. If the author is fitness trainer, they may be repeating information they've heard from other fitness trainers. It happens often, and it's not malicious--they just may have bad information. If the context of the book is sports nutrition then it has a little more weight. If the book cites its references, and there are human studies that show a greater affect, then letting the Examine.com folks know might be a good thing. They try to keep things up to date.

Answer 2

L-Glutamine is used to prevent (or limit) Delayed Onset Muscle Soreness. It is also used by the body's immune system as an energy source. So in taking it on a regular basis you should find that you are less susceptible to catching colds etc. and you shouldn't feel too sore if you are, say, doing heavy weight work.

This is from my own experience of heavy weight training and working in an open office environment (with people and their germs!). For me, I would not be without it.

There are lots of scientific articles out there. I'm not an expert (most of us here are not) so cannot give you a detailed response to how exactly it works, but from my own experience it is worth taking.

Answer 3

There's really nothing worth supplementing except for creatine which even that in itself doesn't have awesome out of this world results. Okay, to be fair, it can give pretty decent results and it has an actual effect that isn't just placebo. And you can literally feel it. But the extent to which it helps is maybe 1 or 2 extra reps. Unless you know you're actually deficient(such as taurine which can cause muscle cramps while lifting) in something I wouldn't bother worrying about it. Most of these products just want to be sold to you, that's all.

Answer 4

Basically, if I have to give a one line answer: Glutamine will help your muscle recover much faster, and won't let you loose muscle easily. So, no it won't help your performance.

However this read might be interesting.

Based upon BodyBuilding site, which I totally second upon here are essential things about Glutamine:

What Is Glutamine?

Glutamine is created in the human body when the non-essential amino acid glutamate (or glutamic acid) is broken down and binds with nitrogen-containing ammonia molecules. Think of glutamine as a kind of nitrogen sponge. It mops up ammonia and shuttles nitrogen between tissues, where it can be used for cell growth and tissue repair, among many other functions. It's been reported that some 30-35 percent of all nitrogen derived from protein breakdown is transported in the form of glutamine. Glutamine can also be broken down to re-synthesize glutamate, which makes glutamine a critical source of ammonia and nitrogen.

Approximately 70 percent of your body's internal glutamine is produced in skeletal muscle, from where it travels to the small intestine, kidneys, and white blood cells. These are the dominant sites of glutamine usage.

Internal levels of this amino acid depend on various factors. Pregnancy and lactation significantly deplete the body's glutamine stores, as do exhaustive exercise, illness, disease, starvation or fasting, rapid growth and development, and other conditions of extreme physiological stress. These are some of the conditions where increasing your glutamine intake or considering supplementation is appropriate.

What Does It Do?

Glutamine—like other alpha-amino acids—is involved in regulating protein synthesis and breakdown. However, there's far more to it than that. Glutamine significantly affects BCAA metabolism, gut barrier maintenance, normal immune function, glucose formation, water transport, neurotransmission, and more.

Your kidneys are a primary consumer of glutamine use that's where the ammonia cleaved from glutamine works to maintain your body's acid-base balance. Anywhere you find ammonia, you'll find glutamine. As metabolic acidosis increases—as in response to intense training or a high-protein diet—renal uptake of glutamine soars. In fact, one study found that just four days of a high-protein, high-fat diet, was enough to cause a 25 percent drop in glutamine levels in the plasma and muscle tissue.

If all of these competing uses begin to outpace your body's ability to produce glutamine, then you may start to show signs of deficiency, including muscle wasting, depleted energy, and increased susceptibility to infections.

What Are the Performance and Physique Applications?

Despite glutamine's various functions, little evidence suggests it will directly result in increased muscle mass, reduced body fat, or gains in muscle strength or power in normal, healthy people. However, given how stressful intense training is on the human body, athletes may see certain benefits from supplementing with significant levels of glutamine, or from stacking it with other supplements.

One study found that when athletes suffered from mild dehydration, supplemental glutamine increased exercise performance and enhanced fluid and electrolyte uptake when combined with a glucose and electrolyte beverage. Supplementation has also been shown to raise levels of growth hormone in response to cycling to exhaustion.

Extracellular concentrations of glutamine have also been shown to activate the signaling pathway mTOR, which is known to be responsible for increasing muscle size. However, here again, the benefits of glutamine supplementation required that other conditions be met: in this case, mTOR signaling appeared to require the presence of BCAAs (leucine, most importantly), as well as some threshold level of cellular hydration.

In another case, collegiate track and field athletes who consumed four grams of glutamine per day for eight weeks, along with a loading and maintenance dose of creatine, saw greater gains in lean body mass than those who used creatine alone. This may sound significant, but it's hard to draw conclusions over a mere eight weeks at such a low dosage. Whether higher doses or a longer study would have resulted in significant differences is anyone's guess.