Food sources of glutamine include cabbage, beets, beef, chicken, fish, beans, and dairy products.

For serving size for specific foods, see Nutrient Rating Chart below at the bottom of this page.

Description Function Deficiency Symptoms Toxicity Symptoms Cooking, storage and processing Factors that affect function

Drug-nutrient interaction Nutrient interaction Health conditions Supplements Food Sources Public Recommendations References

Description

Glutamine is an amino acid synthesized by the body from another amino acid, called glutamic acid or glutamate. Glutamine is referred to as a conditionally essential amino acid because under certain circumstances the body is unable to produce enough glutamine to meet its needs, so it becomes "essential" during these times to obtain glutamine from the diet. The most abundant amino acid in the blood and muscle tissue, glutamine participates in many important physiological functions and is especially important in maintaining the health of the gastrointestinal tract and the immune system. In recent years, glutamine has become increasingly popular among athletes, as it is believed that glutamine helps prevent infections following athletic events and speeds post-exercise recovery.

How it Functions

Glutamine is best known for its ability to serve as a source of fuel for the cells that line the gastrointestinal tract. More specifically, glutamine is the preferred fuel source for cells lining the small intestine. By nourishing these cells, glutamine helps maintain the health and integrity of the gastrointestinal tract. A healthy gastrointestinal tract is vital to preserving overall well-being, as the lining of the gastrointestinal tract serves as a first line of defense against disease-causing microorganisms and also minimizes the absorption of potentially allergenic molecules. Glutamine also serves as a source of fuel for muscle and immune cells.

In addition, glutamine plays a role in maintaining the body's proper acid-base balance. Glutamine is synthesized from glutamate and ammonia. Ammonia is a toxic waste compound with a high pH value, meaning that it is basic (as opposed to acidic). When ammonia levels are elevated, the body clears ammonia from the blood by synthesizing glutamine. If the blood is too acidic (pH too low), the body can break down glutamine into glutamate and ammonia to increae the pH of the blood.

Glutamine also serves as precursor to the antioxidant glutathione, participates in glycogen synthesis (the storage form of carbohydrate), and provides nitrogen compounds for the manufacture of nucleotides which are used to make DNA and RNA.

Deficiency Symptoms

Because glutamine can be synthesized by the body from the amino acid glutamate, glutamine deficiency is not very common. Nevertheless, individuals undergoing severe physical trauma due to infection or extensive burns typically have low glutamine levels. These individuals often exhibit a weakened immune system and heightened intestinal permeability (also called "leaky gut"), which suggests that an inadequate supply of glutamine is associated with reduced immune function and increased intestinal permeability.

Toxicity Symptoms

Consumption of glutamine from food sources alone is not known to cause any harmful effects. Glutamine supplementation, even in doses exceeding 10 grams per day, is also believed to be safe. However, in a few research studies, patients given intravenous nutritional formulas (total parenteral nutrition) containing glutamine developed elevated liver enzymes, a sign of liver toxicity. When the glutamine was removed from the nutritional formulas, the liver enzymes of the patients returned to normal levels. Persons sensitive to monosodium glutamate (MSG) may also want to avoid glutamine supplements, since the body can convert glutamine into glutamate. For this same reason, people with epilepsy or bipolar disorder should use glutamine supplements with extreme caution. To date, Tolerable Upper Intake Levels have not been established for glutamine.

Impact of Cooking, Storage and Processing

There is no research showing problematic effects of cooking, storage, or processing on glutamine levels in food.

Factors that Affect Function

Muscle and blood concentrations of glutamine are rapidly depleted when the body is confronted with any type of physical stress. For example, high-intensity exercise, injury, surgery, burns, infections, and malnutrition cause the body to use up its stores of glutamine, and during these stressful times the body is unable to synthesize glutamine fast enough to meet its needs for this amino acid. Consequently, people under physical stress may be at risk for glutamine deficiency.

Also, the principle site for glutamine synthesis is muscle tissue. As a result, people with low muscle mass, such as the elderly, or muscle wasting diseases (for example, AIDS) may be at risk for glutamine deficiency.

Drug-Nutrient Interactions

Glutamine may be helpful in reducing the side effects associated with chemotherapy drugs, including mouth sores, diarrhea, and muscle and joint pain.

The body metabolizes glutamine to another amino acid called glutamate. Many anti-seizure medications including carbamazepine, phenobarbital, phenytoin (Dilantim TM), primidon (Mysoline TM), and valproic acid (Depakene TM) work by blocking glutamate stimulation in the brain. As a result, persons taking an anti-seizure medication should consult with a health care practitioner before taking a glutamine supplement.

Nutrient Interactions

One common way of making glutamine inside the body is by convering an amino acid called glutamic acid into glutamine. In order for this conversion to take place, a form of niacin-vitamin B3 is required. Glutamic acid is itself often synthesized though a complicated conversion reaction involving three additional molecules. This complex reaction requires vitamin B6 in order to occur. For these reasons, vitamins B3 and B6 can be regarded as helper nutrients when it comes to glutamine sufficiency in the body.

Health Conditions

Glutamine may play a role in the prevention and/or treatment of the following health conditions:

• Alcoholism
• Chemotherapy side effects
• Food allergies
• HIV/AIDS
• Irritable bowel syndrome
• Candida yeast overgrowth
• Post-exercise colds and flu
• Severe burns
• Ulcerative colitis

Form in Dietary Supplements

As a dietary supplement, glutamine is available in protein powders and powdered drink mixes.

Food Sources

Food sources of glutamine include most high-protein foods including beef, chicken, fish, beans, and dairy products.

Public Health Recommendations

No Dietary Reference Intakes have been established for glutamine.

References

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• Darmaun D. Role of glutamine depletion in severe illness. Diabetes Nutr Metab 2000 Feb;13(1):25-30 2000. PMID:15480.
• DiPasquale M. Amino Acids and Proteins for the Athlete: The Anabolic Edge. CRC Press: Boca Raton, FL, 1997 1997.
• Goodman MJ, Skinner JM, Truelove SC. Abnormalities in the apparently normal bowel mucosa in Crohn's disease. Lancet 1976 Feb 7;1(7954):275-8 1976. PMID:9640.
• Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.
• Institute of Medicine. The Role of Protein and Amino Acids in Sustaining and Enhancing Performance. National Academy Press: Washington DC, 1999 1999.
• Labow BI, Souba WW. Glutamine. World J Surg 2000 Dec;24(12):1503-13 2000. PMID:15440.
• Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000 2000.
• Mahan K, Escott-Stump S. Krause's Food, Nutrition, and Diet Therapy. WB Saunders Company; Philadelphia, 1996 1996.
• Medina MA. Glutamine and cancer. J Nutr 2001 Sep;131(9 Suppl):2539S-42S; discussion 2550S-1S 2001. PMID:15400.
• Mithieux G. New data and concepts on glutamine and glucose metabolism in the gut. Curr Opin Clin Nutr Metab Care 2001 Jul;4(4):267-71 2001. PMID:15430.
• Reeds PJ, Burrin DG. Glutamine and the bowel. J Nutr 2001 Sep;131(9 Suppl):2505S-8S; discussion 2523S-4S 2001. PMID:15420.
• Scarpignato C, Pelosini I. Management of irritable bowel syndrome: novel approaches to the pharmacology of gut motility. Can J Gastroenterol 1999 Mar;13 Suppl A:50A-65A 1999. PMID:9590.
• Vardimon L. Neuroprotection by glutamine synthetase. Isr Med Assoc J 2000 Jul;2 Suppl:46-51 2000. PMID:15470.
• Ziegler TR, Bazargan N, Leader LM, Martindale RG. Glutamine and the gastrointestinal tract. Curr Opin Clin Nutr Metab Care 2000 Sep;3(5):355-62 2000. PMID:15450.