Our body uses L-glutamine to create proteins, so-called amino sugars, and to support the production of the super-antioxidant glutathione.
The body also uses L-glutamine to
- increase water retention in muscle cells,
- help signalling cell growth and to
- start intensifying production of protein and glycogen.
Glutamine is therefore a very popular supplement with strength athletes.
Among the free amino acids in human blood, L-glutamine is the most abundant at around 20% of the total. It also exists in a peptide-bonded state, which makes it chemically very stable.
When do we need L-glutamine
A pronounced lack of L-glutamine can be detected particularly during times of metabolic ill-health, such as after difficult operations, or when suffering from injuries or burns. This often means that appropriate supplementation becomes necessary.
Even existing infections can lead to a rapid increase in the need for Glutamine, and these too regularly require extra L-glutamine provision using nutritional supplements.
Above all, this versatile amino acid plays a role in the synthesis of amino sugars and other protein chains in organisms, which means that it is especially needed by tissues with a high cell division rate. Examples of these tissues, aside from the immune system, which also has rapid cell production, include the mucous cells in your small intestine and cells for mucous production in the mouth, such as those on the tongue.
If you do not have a large enough supply of L-glutamine in your body, it can therefore lead to immune system weaknesses and problems in your digestive system due to infections, and it can affect your quality of life significantly.
L-glutamine enables the production of the natural anti-oxidant glutathione, a known preventer of cell damage. It also works as a protection for all cells against oxidising free-radicals and can thus act against the development of cancer too.
As if that were not enough, this amino acid regulates the stability of acids and bases in the body, keeping proteins active, and through this ensures the correct execution of metabolic processes.
Foods high in L-glutamine
The recommended minimum dose of L-glutamine is around 10g per day, but can also be higher if certain specific factors are at play. In most need are competitive sportsmen and patients with liver or kidney diseases, who frequently need higher doses of up to 40g a day. In those cases nutritional supplements must normally be called upon because natural foodstuffs only contain very low levels of L-glutamine. The need for L-glutamine can also rise sharply during chemotherapy, which is why supplements can often be helpful then.
As L-glutamine is denatured by heat, meaning that its properties are diminished, it is mostly destroyed in the use of treatment processes at high temperatures. Keeping products which contain L-glutamine in direct sunlight over long periods will result in a continual reduction of the vital amino acids, so storage in dark places is recommended.
Next to cheese, the German cottage-cheese like product quark is known as the foodstuff containing the most L-glutamine, and thus it should be factored into your meal plans to provide you extra amounts of Glutamine. Milk and yogurt are also good providers of L-glutamine, although they contain markedly less in comparison. Raw and smoked meat contain some L-glutamine, as do soya and wheat products, which can all be used to reach your recommended daily dose.
Doses of L-glutamine
There are different recommendations as to when in the day L-glutamine can best be absorbed into the body. The theory that has stayed its ground the longest is one of consumption both in the morning and the evening. To best strengthen your immune system, taking one dose of 5g of L-glutamine after getting up and another 5g before going to bed is recommended. If your aim is to build up muscle mass with higher glycogen storage in your muscle tissue, you should take around 5 to 10 grams of Glutamine before and after working out.
If your L-glutamine levels drop to lower than your body needs, the consequences can be threatening. Not consuming enough L-glutamine over long periods of time can lead to your immune system having lower levels of activity and problems with absorbing vitamins.
Thus, not only do you then have a higher risk of infections, but also a lack of many other important nutrients because your intestine has not managed to absorb all the nutrients from food you have consumed, leaving them unused.
Functions of L-glutamine
L-glutamine is used in creating proteins and is therefore involved in the composition of many protein products. Amongst other functions, it helps to create so-called amino sugars, which assist the body in combating things like osteoarthritis, and supports production of glutathione.
Glutamine has been shown to have positive effects on Human Growth Hormone maintenance, immune system function, cell volume, and protein substrate recycling for increased proteine synthesis. These advantages make Glutamine a sensible anabolic supplement which is beneficial & popular with bodybuilders. Supplementation of 5-10g a day is beneficial to restore lost Glutamine in muscle cells1.
As well as this, it puts pressure on fluid retention in cells so that the cell volume can ultimately increase.
The body takes this increase in cell water retention as a signal for cell growth and starts to intensify production of protein and glycogen with the aim of increased performance of muscle cells.
At the same time, L-glutamine prevents muscle catabolism and improves your body’s ability to recover during sleep.
If, however, you are suffering from infection or trauma, the amount of free L-glutamine in your body’s muscle systems will reduce by up to 50%, and symptoms like tiredness and fatigue will occur.
Because L-glutamine also provides energy for the digestive cells, it aids those cells in their regeneration and renewal, therefore influencing the absorption ability of the intestine. Cells which divide quickly, such as those in the immune system too, are very reliant on having a supply of L-glutamine. This is why medical procedures like bone marrow transplants have much lower death rates when a targeted supplementary regime of L-glutamine has been given beforehand.
Other uses of L-glutamine can be found in the nervous system, as L-glutamine is very chemically similar to the neurotransmitter glutamic acid. To transport messages in the body, the nerve cells must be stimulated successfully in a row.
After this stimulation, the neurotransmitter has to be transported back to the earlier cell which previously released it in order to pass along the message. When back in the old cell, it is turned into L-glutamine so that it does not accidentally excite the next cell and send a false message.
In this way, a second and unwanted excitement of the nerve cells can be avoided, and finally L-glutamine is turned back into glutamic acid for the cycle to start again when needed.
As L-glutamine also has a certain anti-oxidative potential, it can protect human cells from destruction by free radicals, and is therefore able to, up to a certain point at least, prevent degenerative neurological illnesses like Alzheimer’s or Parkinson’s.
L-glutamine in use against illnesses
Autoimmune diseases in the digestive system like Crohn’s disease are almost always accompanied by reduced permeability of the intestinal wall, which ultimately leads to poor utilization of vitamins from the food you have eaten. Indian researchers have now proven that taking L-glutamine supplements as part of your diet (0.5g per kilo of body weight) can drastically increase intestinal permeability and thus improve the vital substances coming into your body. 2
As well as this, bodily activity has an essential influence on generation of L-glutamine and also regulates its uptake.
It’s no wonder that you have depleted stocks of L-glutamine in your body if you push yourself to physical limits and have a difficult training programme – but this is associated with weaknesses in your immune system.
L-glutamine accompanying cancer treatment
Another important field of application for L-glutamine in fighting illnesses is in cancer treatment. In the past, several studies were carried out, showing L-glutamine’s effects against tumours. 4
In their conclusions the researchers decided that appropriate L-glutamine supplementation can considerably improve the metabolism and entire clinical state of cancer patients without increasing tumour growth. This affects, among other things, an increase of the immune system’s activity, increased rate of cell renewal and a stronger creation of glutathione. Furthermore, L-glutamine can lower the risks of chemotherapy and radiotherapy, leading to the patient being put under less strain.
L-glutamine and glutamate
Glutamate is a flavour enhancer mostly known for being from the Far East. As it is an edible product, it is permitted by many laws regulating nutrition in amounts up to 10g per kilo of food. Glutamate is the salt of glutamic acid and is therefore chemically not comparable to, nor to be confused with, the amino acid L-glutamine.
As a food additive, the different forms of glutamate must be identified on packaging using the E-numbers E621 to E625. Companies prefer, however, to label their food with words like ‘spices’ or ‘yeast extract’, which is also permitted.
Allegedly toxic effects of glutamate in high doses have never been proven. In the 1940s children were administered with over 40g of glutamate per day over several months.
This was done under the belief that it could boost intellectual abilities. Neither an intellectual increase nor long-term toxic effects could be proven by the study.
L-glutamine is indeed not an essential amino acid because the body can synthesis it, but it is popular fields of sport and weight training to avoid the threat of muscle catabolism post workout. Among other things, it is used to provide energy for all of your cells and it regulates the stability of acids and bases in the body, keeping proteins active. Due to its multitude of positive qualities, scientists have started to use L-glutamine against illnesses such as cancer and Crohn’s because it can alleviate symptoms and lead to a faster recovery.
- Matt Samuels, RD. “Glutamine and it’s Role in Athletic Performance” http://www.afpafitness.com/articles/articles-and-newletters/research-articles-index/nutrition-wellness/glutamine-and-its-role-in-athletic-performance/ ↩
- “Benjamin J et al.: Glutamine and whey proteine improve intestinal permeability and morphology in patients with Crohn´s disease: A randomized controlled trial; Dig Dis Sci, 2011 Oct 26” ↩
- “Aostini, Francesco; Biolo, Gianni: Effect of physical activity on glutamine metabolism; Current Opinion in Clinical Nutrition & Metabolic Care; January 2010 – Volume 12 – Issue 1” ↩
- “Katharina S Kuhn et al.: Glutamine as indispensable nutrient in oncology: experimental and clinical evidence; European Journal of Nutrition, Volume 49, Number 4/ Juni 2010” ↩