Glutamine: What is it?
Glutamine is a non-essential amino acid meaning that it is produced by the body. However, during times of injury, illness, hard training or overtraining, the body cannot produce enough glutamine to keep up with the amount of glutamine needed.
Glutamine: Immune support
Glutamine is needed for cell growth and to help fuel the immune system. When training at a high intensity, the levels of glutamine in your blood and muscles begin to fall. When blood levels of glutamine are low, our immune system is more exposed to infection and illness.
One study cited by Bean (2007) concluded that marathon runners that took 5g of glutamine straight after and 2 hours after the event had a reduced occurrence of illness in the week after the race. Just 19% of the glutamine-supplemented athletes noted any form of illness or infection compared to 51% of the athletes that received a fake supplement with no active ingredients.
Glutamine: Overtraining and Recovery
Overtraining is a state where the body has insufficient time to recover from the stress of exercise before the next session takes places. It is thought that hard training leads to depletion of glutamine due to the body’s inability to make as much as the body requires (Shepherd, 2005).
It has also been suggested that when glutamine is taken after exercise with carbohydrates that it enhances the storage of carbohydrate in the muscles by up to 25% (Bowtell et al, 1999) which ensures that there is muscle fuel available for future sessions and further reduces the risk of overtraining while improving recovery and future exercise performance.
Glutamine and Body composition
Supplementing a diet with glutamine can cause a 4 fold increase in growth hormone release, which may encourage protein synthesis (muscle building) while also reducing levels of a stress hormone called cortisol, which breaks muscle down (Gleeson, 2008).
Glutamine: When to use
L-Glutamine is the standard supplement used, this means it is an isolated form of an amino acid and has no other amino acids in the powder, this is useful as it means that it doesn’t have to fight with other amino acids for absorption from the stomach. Glutamine is found in protein powders, with products such as GRS – 5, Omni hardcore and 100% whey having added glutamine to maximise uptake by the muscles, stomach and blood. Other suggestions that taking L-glutamine powder before bed may aid growth hormone release during sleep and reduce muscle breakdown over the fasting night time period.
Bean, A (2007) Sports Supplements: Which nutritional supplements really work.
A & C Black, London
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Casrtrell LM, Poortmans JR, Newsholmes EA (1996) Does glutamine have a role to play in reducing infections in athletes. European Journal of Applied Physiology: 73: 488 – 90
Gleeson (2008) Dosing & efficancy of glutamine supplementation in human exercise & sports training. The Journal of Nutrition: 138: 2045s – 2049s
Parry- Billings, M, Evans J, Calder PC, Newsholme, EA (1990) Does glutamine contribute to immune suppression after major burns? Lancet; 336:523 –5
Rowbottom DG, Keast D, Morton AR (1996) The emerging role of glutamine as an indicator of exercise stress and overtraining. The Journal of Sports Medicine; 21(2): 80 – 97
Shephard RJ (2005) Chronic fatigue syndrome: A brief review of functional disturbance and potential therapy. Journal of Sports medicine & Physical Fitness: 45; 381 – 392