Megadose Glutamine does Nothing for Strength Athletes
Glutamine [structural formula shown below] will no doubt remain on the shelves of sports supplements shops for years to come. If the study that sports scientists at the University of Saskatchewan in Canada did can’t change this, nothing can. It showed back in 2001 that glutamine doesn’t work.
Glutamine is not an essential amino acid. It’s an amino acid that the body makes itself, from other amino acids. Half of the free amino acids in the body consist of glutamine.
If you look at the fundamental research that has been done on the role of glutamine in physical exertion, it’s not that surprising that supplements manufacturers have put glutamine on the market. If your blood becomes acid, your body makes an alkaline substance from glutamine to neutralise the acid level in your blood. If your body doesn’t have enough glutamine available at that moment, it gets the adrenal glands to make more cortisol, which forces your muscles to release glutamine.
On top of that, glutamine converts easily into glucose. Many types of cell prefer to use glutamine as a source of energy.
In the mid 1990s an American researcher also discovered that just 2 g glutamine increases the growth hormone concentration by a factor 5. [Am J Clin Nutr. 1995 May; 61(5): 1058-61.] In this study, 9 test subjects were given glutamine after eating a light breakfast. The glutamine was dissolved in a glass of Coke.
Megadose glutamine does nothing for strength athletes
All this would be enough to believe in glutamine supplementation. If you give athletes extra glutamine, they produce less cortisol during exhaustive training, their muscle cells convert less amino acid into glucose and they synthesise more growth hormone. Demonstrating that strength athletes show more progression when they take glutamine supplements looked like a mere formality.
But because you do have to go through the formalities, Canadian scientists did an experiment in 2001 involving 31 male and female strength athletes aged between 18 and 24.
Half of the subjects were given 0.9 g glutamine per kg lean body mass every day for 6 weeks. That was equivalent to about 45 g glutamine a day – the highest dose you can give without it becoming toxic. The subjects divided the glutamine over two intakes: one just after training and one just before going to sleep. On the days that they didn’t train, the subjects were allowed to take the daytime dose whenever they wanted, but the night-time dose was taken at the same time as on training days.
The other half of the subjects were given a placebo. The placebo group had exactly the same progression as the glutamine group by the end of the experiment.
A popular theory is that all sorts of cells other than muscle cells, like gut, brain and immune cells slurp up all the glutamine before it can have an ergogenic effect.
Eur J Appl Physiol. 2001 Dec;86(2):142-9.