Amino Acids For Muscle Growth
Any bodybuilder, athlete or anyone who works out regularly should know that in order to get muscles to grow, we need an abundant supply of protein or amino acids, especially the essential amino acids. If you didn’t, well now you do. Perhaps of even greater importance is the amount of Leucine that we consume. Leucine is not only an essential amino acid, but it’s also a branched chain amino acid which studies have shown to be perhaps the most potent stimulator for muscle growth.
An in depth look at Leucine and its effects on muscle growth can be found here, however in a brief explanation of how Leucine affects muscle growth; it does so by activating a protein known as the Mammalian Target of Rapamycin Complex 1 or mTORC1, which is involved in several processes, one of which involves increasing protein synthesis. An abundant supply of essential amino acids are also important to help activate and boost the activity of mTORC1, however, previous studies show that Leucine is the most important one.
Glutamine - Early Days
Glutamine, a non essential amino acid was considered earlier by the sports community as a crucial amino acid to maximise growth and muscle adaptations. This was perhaps mostly due to the fact that glutamine is not only the most abundant non-essential amino acid in our body, but because studies have been able to show that glutamine levels can be depleted by up to 50% with exercise. Ergo, replenishing this supply is crucial for optimum performance. Indeed this is the case as Glutamine is essential in helping to maintain a healthy immune system. Those participating in regular or intense exercise run the risk of having a depressed immune system which poses an increased infection risk, a hindrance to training and sustained growth. Thus supplementing with Glutamine may help prevent this from happening.
Glutamine - Lack of Support
However, over time, the positivity towards glutamine decreased as there weren’t strong enough studies showing that glutamine supplementation was able to significantly enhance muscular growth or strength. The most often quoted study in favour of the supplementation of glutamine would be Colker et al (2000) who showed that supplementation with both 5g of glutamine and 3g of BCAA's in an enriched whey protein shake was able to result in a higher muscle mass increase over the control group. However another study by Candow et al (2001), which supplemented participants with glutamine at 0.9g/kg of lean muscle mass, showed no muscle performance gains, changes in muscle degradation or body composition. With few studies and some conflicting results, the support for glutamine supplementation waned. Until recently….
Glutamine - A Changing Opinion
So glutamine by itself is not enough to increase muscle mass and strength but perhaps, it works best when combined with BCAAs, especially that of Leucine. Esbjornsson et al (2012) was able to show recently that acute spurts of intense activity lowered the amount of Leucine in the blood more so in males than in females. In contrast, females had a reduced amount of ammonia in the blood and muscles and a higher level of Glutamine. The results also showed that there was a significant link between the decreased Leucine and increased concentration of muscle ammonia. This prompted the authors to suggest that higher levels of Glutamine in the females, which helps to buffer ammonia are critical in supporting Leucine levels after exercise.
In addition Chiu et al (2012) found that cells deficient in Glutamine had decreased mTORC1 activity, even with adequate Leucine and essential amino acids. In which case, Glutamine is extremely helpful and necessary to maximise mTORC1 function. Combining these two studies, it becomes obvious that not only does Glutamine ensure a reduction in the degradation of the anabolic BCAA Leucine, but it is also necessary to maximise how Leucine works through mTORC1. In simpler terms, Glutamine may activate mTORC1 distinctly from Leucine but can also work synergistally or better with Leucine.
Have Some Glutamine Today
Glutamine, the most abundant non essential amino acid in our body is not only crucial in helping to boost your immune system but it may also offer anabolic potential too. So perhaps it might be in your favour to add Glutamine back into your supplement regime again to help you make the most out of your current supplements. In terms of dosage, 5g before and after your workouts is considered ideal.
1. Colker CM: Effects of supplemental protein on body composition and muscular strength in healthy athletic male adults. Curr Ther Res 2000, 61(1):19-28.
2. 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, 86(2):142-9
3. Esbjörnsson M, Rooyackers O, Norman B, Rundqvist HC, Nowak J, Bülow J, Simonsen L, Jansson E. ‘Reduction in plasma leucine after sprint exercise is greater in males than in females.’ Scand J Med Sci Sports. 2012 Jun;22(3):399-409. doi: 10.1111/j.1600-0838.2010.01222.x. Epub 2010 Sep 7.
4. Chiu M, Tardito S, Barilli A, Bianchi MG, Dall'asta V, Bussolati O. ‘Glutamine stimulates mTORC1 independent of the cell content of essential amino acids.’ Amino Acids. 2012 May 8. [Epub ahead of print]