What is Glutamine?
Glutamine is the most abundant amino acid (building block of protein) in the body. The body can make enough glutamine for its regular needs. But during times of extreme stress (the kind you experience after heavy exercise or an injury), your body may need more glutamine than it can make. Most glutamine is stored in muscles, followed by the lungs where much of the glutamine is made.
Glutamine is important for removing excess ammonia (a common waste product in the body). It also helps your immune system function and may be needed for normal brain function and digestion.
You can usually get enough glutamine without taking a supplement because your body makes it and you get some in your diet. Certain medical conditions, including injuries, surgery, infections, and prolonged stress, can lower glutamine levels. In these cases, taking a glutamine supplement may be helpful.
Benefits of Glutamine Supplementation
“Several studies show that adding glutamine to enteral nutrition (tube feeding) helps reduce the rate of death in trauma and critically ill people. Clinical studies show that taking glutamine supplements strengthens the immune system and reduce infections, particularly infections associated with surgery.”
“Glutamine may help prevent or treat multiple organ dysfunction after shock or other injuries among people in the intensive care unit. Glutamine supplements may also help in the recovery of severe burns.”
“Glutamine helps protect the lining of the gastrointestinal tract known as the mucosa. For that reason, some researchers believe that people who have IBD (ulcerative colitis and Crohn disease) may not have enough glutamine. However, two clinical trials found that taking glutamine supplements did not improve symptoms of Crohn disease.”
“Athletes who train for endurance events (like marathons) may reduce the amount of glutamine in their bodies. It is common for them to catch a cold after an athletic event. Some experts think that may be because of the role glutamine plays in the immune system. For this select group of athletes, one study showed that taking glutamine supplements resulted in fewer infections. The same is not true, however, for exercisers who work out at a moderate intensity.”
Sources and How to Take It
Dietary sources of glutamine include plant and animal proteins such as beef, pork, poultry, milk, yogurt, ricotta cheese, cottage cheese, raw spinach, raw parsley, and cabbage.
Glutamine, usually in the form of L-glutamine, is available by itself, or as part of a protein supplement. These come in powders, capsules, tablets, or liquids.
Standard preparations are typically available in 500 mg tablets or capsules.
Take glutamine with cold or room temperature foods or liquids. It should not be added to hot beverages because heat destroys glutamine.
Some athletes can have high intakes of l-glutamine because of their high energy and protein intakes and also because they consume protein supplements, protein hydrolysates, and free amino acids.
Acute intakes of glutamine of approximately 20-30 g seem to be without ill effect in healthy adult humans and no harm was reported in 1 study in which athletes consumed 28 g glutamine every day for 14 d. Doses of up to 0.65 g/kg body mass of glutamine (in solution or as a suspension) have been reported to be tolerated by patients and did not result in abnormal plasma ammonia levels. However, the suggested reasons for taking glutamine supplements (support for immune system, increased glycogen synthesis, anticatabolic effect) have received little support from well-controlled scientific studies in healthy, well-nourished humans.
“Alterations in amino acid transport-as GLN shares the transporters with other amino acids, enhanced GLN intake may impair amino acid distribution among tissues and their absorption in the gut and kidneys.”
“Effect of the withdrawal of GLN supplementation-due to the adaptive response of the organism to enhanced GLN consumption, the withdrawal of GLN may enhance the risk of health problems resulting from GLN deficiency. It is concluded that enhanced intake of GLN has substantial side effects, and long-term studies should be performed to justify chronic consumption of a GLN-enriched diet.”
“Glutamine powder should not be added to hot beverages because heat destroys glutamine. Glutamine supplements should also be kept in a dry location.”
“People with kidney disease, liver disease, or Reye syndrome (a rare, sometimes fatal disease of childhood that is generally associated with aspirin use) should not take glutamine.”
“People who have psychiatric disorders, or who have a history of seizures, should use caution when considering supplementation with glutamine. Some researchers feel that taking glutamine may worsen these conditions.”
“Many elderly people have decreased kidney function, and may need to reduce their dose of glutamine.”
Glutamine (abbreviated as Gln or Q; encoded by the codons CAA and CAG) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain amide which replaces the side chain hydroxyl of glutamic acid with an amine functional group, classifying it as a charge neutral, polar (at physiological pH) amino acid. It is non-essential and conditionally essential in humans, meaning the body can usually synthesize sufficient amounts of it, but in some instances of stress, the body’s demand for glutamine increases and glutamine must be obtained from the diet.
In human blood, glutamine is the most abundant free amino acid, with a concentration of about 500–900 µM.