Dictionary:

glutamine

  (glū'tə-mēn')

Also from Answers.com... Asthma How to prevent and treat an asthma attack.

A nonessential amino acid, C₅H₁₀N₂O₃, occurring widely in plant and animal tissue and proteins and produced commercially for use in medicine and biochemical research.

[GLUT(EN) + AMINE.]

Key Terms: Arginine, Beta-hydroxy-beta-methylbutyrate, Bone marrow transplant, Cachexia, Gluconeogenesis, Glutaminase, Glutathione, Hepatic veno-occlusive disease, Lymphocyte, Mucositis, Natural killer cell, Parenteral nutrition, Short bowel syndrome.

Definition

Glutamine is an amino acid that is used as a nutritional supplement in the treatment of a variety of diseases, including cancer.

Purpose

Glutamine is the most abundant free amino acid in the human body and, in addition to its role as a component of protein, serves a variety of functions in the body. It is a non-essential amino acid because it is made by body cells. In addition most dietary protein contains ample amounts of glutamine and healthy people usually obtain all the additional glutamine that they need in their diet.

Cancer and other diseases and injuries induce a state of physiologic stress that is characterized by glutamine deficiency. This deficiency is aggravated by chemotherapy and radiation therapy used to treat cancer. Therefore, glutamine is sometimes described as a conditionally essential amino acid that needs to be supplemented when the body is stressed.

Cancer-related glutamine deficiency can reduce the tolerance of normal tissues to cancer treatment, necessitating reduced doses and possibly diminishing the effects of treatment. Glutamine supplementation may help protect normal tissues from chemotherapy and radiation while sensitizing tumor cells to these agents.

Increasingly in the early 2000s, glutamine is considered an important component of both oral and parenteral (intravenous) nutrition (PN) therapy during high-dose chemotherapy and radiation treatment. It also is used as a nutritional supplement for bone marrow transplant (BMT) patients, particularly those with leukemia or lymphoma whose bone marrow has been destroyed with high-dose chemotherapy.

Glutamine supplementation appears to do the following:

• improve nitrogen retention
• decrease the incidence of infection
• decrease the length of hospitalization, saving thousands of dollars

Glutamine supplementation also appears to reduce the incidence of gastrointestinal, nervous system, and heart complications arising from cancer therapy. Oral glutamine may reduce diarrhea and the duration and severity of other gastrointestinal side effects of chemotherapy. In particular it appears to help prevent the intestinal toxicity of the cancer drug fluorouracil. Glutamine may reduce the incidence and severity of mucositis, a common, painful inflammation of the membranes of the oral cavity that can result from chemotherapy. Rinsing with a glutamine-containing mouthwash can help reduce mouth sores from radiation and chemotherapy treatments. Glutamine also appears to reduce the need for antifungal agents during chemotherapy.

Description

Glutamine (Gln) or L-glutamine is available by prescription as a powder called NutreStore. It is taken as an oral suspension for treating short bowel syndrome. It also is available in nutritional formulas and as an individual nutritional supplement. As an intravenous supplement it may be supplied in the form of alanyl-glutamine dipeptide or glycyl-glutamine dipeptide.

Metabolic Effects

There is much speculation about why glutamine appears to be a beneficial adjunct for cancer treatment. Glutamine is required for numerous metabolic processes, including the following:

• Regulation of cell growth and function.
• Synthesis of proteins and nucleic acids (DNA and RNA).
• Movement of nitrogen in the body. Glutamine is the body's primary means of transferring ammonia in a nontoxic form.
• Gluconeogenesis—the formation of glucose from protein and fat.
• Maintenance of acid-base equilibrium in the body.
• As a major fuel for intestinal mucosal cells.
• Improved kidney cell function.

Tumors cause major disruptions in nitrogen and glutamine metabolism. The high rate of protein synthesis in rapidly growing tumors requires a continuous supply of amino acids. Tumors are referred to as nitrogen traps because they actively compete with normal tissues for nitrogen-containing compounds such as glutamine. Tumors also are referred to as glutamine traps because glutamine moves from normal tissues to tumors. Some evidence suggests that glutamine supplementation may diminish tumor growth, in part by improving overall protein metabolism.

Cancer cells generally move glutamine across their cell membranes at a faster rate than normal cells. Glutaminase—the enzyme that breaks down glutamine—has increased activity in cancerous cells, and there is evidence that glutaminase activity correlates with the proliferation of malignant cells.

Immunological Effects

Glutamine and arginine may be referred to as immunonutrients because of their important roles in the functioning of the immune system that protects the body from foreign entities, including cancer cells. Glutamine helps to regulate the immune system and is a major fuel for lymphocytes (a type of white blood cell) and other immune system cells. In cancer patients undergoing chemotherapy and total body irradiation, glutamine has been shown to boost the immune system by increasing the levels of circulating lymphocytes and other cells of the immune system.

In patients undergoing chemotherapy with radioactive drugs for advanced esophageal cancer, oral glutamine supplementation helped to protect immune system function by causing lymphocytes to divide and multiply. Glutamine supplementation also reduced the permeability of the gastrointestinal tract in these patients.

Antioxidative Effects

Glutamine appears to be the rate-limiting factor for the production of liver and intestinal glutathione (GSH), a chemical that protects cells against the damaging effects of oxidation. As cancer cells deplete the glutamine in normal cells, the levels of GSH drop. It has been suggested that PN without added glutamine may itself decrease GSH levels and increase oxidative damage. By increasing GSH levels, oral glutamine supplementation also may increase the selectivity of anti-cancer drugs by protecting normal cells from oxidative damage caused by the drugs. Glutamine supplementation also appears to protect normal cells from radiation-induced oxidative damage. Since GSH depletion reduces the activity of natural killer cells (immune system cells that destroy cancer cells) glutamine supplementation may increase GSH levels and restore natural-killer-cell activity. Some evidence suggests that this may diminish tumor growth.

Effectiveness

As of 2005, glutamine supplementation during cancer therapy and bone marrow or stem cell transplantation remains under investigation. Although some studies have demonstrated specific benefits in at least some types of cancer, numerous animal and human studies have shown no clear benefit or any effect on tumor response or on the side effects of chemotherapy. However, one study suggested that glutamine supplementation could increase the likelihood of long-term survival in patients with cancers of the blood.

Other studies have found that glutamine supplementation in cancer patients receiving high-dose chemotherapy and BMT decreases the incidence and/or severity of the following:

• chemotherapy-associated mucositis
• diarrhea associated with irinotecan, a drug used to treat colon and rectal cancers
• nervous system damage caused by the anticancer drug paclitaxel
• cardiac toxicity caused by the drug anthracycline

Combination Supplements

Cancer-related cachexia (severe malnutrition, weakness, and muscle-wasting) is caused by the increased breakdown of proteins and reduced protein synthesis in patients with advanced cancer. One study demonstrated that supplementation with specific nutrients, including a combination of glutamine, beta-hydroxy-beta-methylbutyrate (HMB), and arginine, could reverse these processes. Patients with stage IV cancer who received this combination gained significant fat-free body mass in four weeks and continuing over a period of 24 weeks, as compared to control patients who lost body mass.

Case studies have reported that the administration of glutamine orally and intravenously, in combination with oral vitamin E, decreases the signs and symptoms of hepatic veno-occlusive disease. This is an often-fatal type of liver failure that occurs in patients treated with high-dose chemotherapy in preparation for BMT.

Recommended Dosage

Glutamine supplementation generally is started three to five days before chemotherapy. The glutamine dosage used to treat short bowel syndrome is 5 g, six times per day for up to 16 weeks. It is taken with food, every two to three hours while awake. Nutritional guidelines for cancer patients generally recommend 2–4 g of glutamine per day to protect against radiation-induced enteritis (intestinal inflammation).

Dosages used in clinical studies of glutamine supplementation in cancer patients vary:

• 18–30 g per day, orally
• 10 g three times per day, orally
• 0.57 g per kg (2.2 lb.) of body weight per day
• 50 g per day of dipeptide glycyl-glutamine, in-travenously
• 0.4 g per kg (2.2 lb.) of body weight per day of dipeptide glycyl-glutamine, intravenously
• 14 g of glutamine per day in combination with arginine and HMB for up to 24 weeks

Precautions

Glutamine, taken orally or by injection, appears to be safe; however, precautions include the following:

• Excess amino acids may be excreted in the urine without being absorbed by the body.
• Excess amino acids can harm the kidneys.
• Glutamine, like any drug, can potentially cause an allergic reaction.
• It is not known whether glutamine supplementation is safe during pregnancy or while breastfeeding.
• Elderly patients may be more sensitive to glutamine supplementation, requiring lower doses.
• Glutamine can worsen liver disease.

Since glutamine is essential for the growth of both healthy and cancerous cells, it is theoretically possible that glutamine could fuel tumor cells, leading to more rapid growth. However, there is no evidence to suggest this, nor is there evidence that glutamine supplementation adversely affects treatment or clinical outcomes.

Side Effects

Glutamine supplementation in cancer patients does not appear to cause side effects or adversely affect quality of life.

Interactions

Glutamine supplementation is not known to negatively interact with other medications.

—Margaret Alic, Ph.D.

A non-essential amino acid, chemically the amide of glutamic acid.

Description

In healthy individuals, glutamine is a neutral, nonessential amino acid. Amino acids are critical to humans, since they form the proteins that are the building blocks for many body tissues, including muscles. Glutamine is the most abundant amino acid in our bodies. It performs several important functions in the body, particularly in those that are stressed because of certain diseases or conditions. Glutamine can be added to the body medically by physicians or through dietary supplements that people purchase without prescriptions.

General Use

Researchers continue to study glutamine's properties and effects. It is the most plentiful amino acid in the bloodstream and the body continues to produce it unless some sort of stress occurs. Cancer, burns or trauma, excessive exercise, and certain other stressful situations to the body may cause glutamine levels to drop.

Research suggests that when glutamine levels fall and are not replaced, several body functions are affected, particularly within the digestive tract. Glutamine also is considered important to overall immunity, or ability to fight off diseases and infections. In the past few decades, interest has grown for use of glutamine in helping cancer patients. Research continues on using glutamine therapy to help patients with sepsis, burns, trauma, inflammatory bowel disease, acquired immune deficiency syndrome (AIDS), bone marrow transplants, and other potential diseases and conditions.

Some clinical research has reported glutamine aided patients with multiple trauma and burns by helping them fight off infections. It may help AIDS patients put on weight at a much lower cost, and with fewer complications, than human growth hormone. Athletes who overtrain have higher rates of infectious diseases and allergies; it is thought a diet high in glutamine can help improve these athletes' immune functions.

As more people have begun looking for ways to enhance fitness, they have turned to protein supplements.

In 2003, it was reported that more than 1.2 million athletes used some type of performance-boosting supplement. Glutamine is used in the fitness industry as a supplement for bodybuilders who want to reduce muscle breakdown, or for recreational athletes on vigorous training schedules who feel the supplement fuels their immune systems.

Preparations

As a protein, glutamine occurs naturally in some foods, including meat, fish, legumes, peanuts, eggs, tofu, and dairy products. It also is highly concentrated in raw cabbage and beets. Cooking can destroy glutamine, particularly in vegetables. Much of a person's glutamine needs, even when exercising hard, can come from food sources. A 3–oz serving of meat contains about 3–4 grams of glutamine.

Glutamine supplements come in several forms. Some manufacturers sell tablets that also contain antioxidants (vitamins). The most common forms of glutamine supplements are protein powders that can be added to liquids and prepared protein drinks and shakes. Another amino acid called alanine may be combined with glutamine. The combined protein supplement is called alanyl-glutamine. The powder form is probably the most convenient and least expensive form of the supplement. When glutamine is used for medical purposes in a hospital setting, it may be administered via an enteral route, or through a tube directly into the intestine.

In 2002, the powder cost about 10 cents a gram, while the capsules cost between 12 and 23 cents per gram. Capsules deliver fewer grams of glutamine than the powder and the glutamine in capsules does not absorb as quickly as that in powder. The powder reportedly tastes mild and is not noticeable when added to favorite drinks.

Recommended doses of glutamine for fitness uses such as bodybuilding vary, but generally are 8–20 grams (g) a day and average about 15 g a day. Cancer patients on glutamine therapy may take a higher dose, about 30 g a day. An average daily therapeutic dose for the general public is 1.5–6 g.

Precautions

The powdered form of glutamine should be dissolved in a liquid and consumed quickly before it breaks down. Some literature recommends taking glutamine immediately before or after meals, or at the same time as eating protein, usually twice per day.

Glutamine is marketed as a dietary supplement, and therefore, the products are not regulated the same as prescription drugs. Those who take glutamine must be cautioned to carefully read labels; some supplements are not what they appear to be. In 2004, the U.S. Food and Drug Administration (FDA) outlined a new process to try to work toward better safety of the 29,000 dietary supplements on the American market. However, consumers still need to be cautious of contents and claims of dietary supplements. It also is important to follow dosage directions and/or to check with a physician or other certified medical or complementary medicine practitioner to ensure the correct dose is being taken. Finally, while many fitness promoters tout glutamine's effects, some researchers disagree with the science behind the claims. In time, more and larger clinical trails may be able to clear up the controversy over glutamine's ability to increase muscle size and strength in recreational athletes.

Side Effects

No noticeable negative side effects of glutamine at recommended dosage and preparations had been reported as of May 2004. However, long-term research is ongoing.

Interactions

As of May 2004, glutamine has not been shown to interact with any particular drugs or with other supplements. However, research on glutamine supplements is limited and ongoing. Consumption of cabbage can worsen goiters and a condition called hypothyroidism. Since glutamine is not a regulated substance, it is best to consult a physician when adding the supplement to the diet and to mention regular glutamine supplementation to a health professional when he or she is treating a patient for a new disease or condition, or adding or changing drug therapy.

Resources

Periodicals

"Advanced Nutrition: Absorbing Stuff from Team FLEX." Flex (February 2003): 183–191.

Krenkel, Jessica A. "Glutamine Supplementation in Bone Marrow Transplantation (BMT)." Topics in Clinical Nutrition (September 2002): 83–91.

Nick, Gina L. "Impact of Glutamine–rich Foods on Immune Function (Medicinal Properties in Whole Foods." Townsend Letter for Doctors and Nurses (April 2002): 148–157.

"Protein Supplements of Little Use, Says Trial." Nutraceuticals International (May 2001).

Rowley, Brian. "Glutamine Facts. (Hotline: Nutrition and Supplements)." Muscle & Fitness (January 2002): 38–42.

Rowley, Brian. "Amino Acids Essential for Muscle Growth. (Stack of the Month)." Muscle & Fitness (August 2003): 184–185.

Yeager, Selene. "Take a Powder. (Fitness Chick)." Bicycling (August 2003): 77–78.

Organizations

Center for Science in the Public Interest. 1875 Connecticut Avenue NW, Suite 300, Washington, DC, 20009. 202-332-9110. .

Other

Bird, Patrick J. Glutamine Supplements and Exercise University of Florida. [cited June 6, 2004]. .

"Glutamine." QFAC Bodybuilding [cited June 6, 2004]. .

"Report Offers Science-based Process and Guidelines to Evaluate Safety of Dietary Supplements." The National Academies Press Release. .

[Article by: Teresa G. Odle]

For more information on glutamine, visit Britannica.com.

An amino acid derived from glutamic acid. It is a constituent of proteins and plays an important role in protein metabolism. Glutamine is classified as a non-essential amino acid, but premature infants cannot make it fast enough to satisfy their requirements for protein synthesis, so they must be provided with supplements. This has led to the idea (as yet unsubstantiated) that glutamine supplementation might stimulate muscle growth in adults. Plasma glutamine levels may reflect the ability of an athlete to repair muscles after intense exercise. Low plasma glutamine levels have been associated with overtraining and exercise-induced muscle damage.

Gln; an amide of glutamic acid, an amino acid occurring in proteins; it is an important carrier of ammonia to the kidney where it is released by glutaminase.

• g. synthetase — enzyme catalyzing the synthesis of the amino acid, glutamine from glutamate ammonia and ATP. Major means of detoxifying ammonia from amino acid catabolism in peripheral tissues and then transporting the ammonia as the amido-N in glutamine to the liver of kidney.

Chemical structure of L-glutamine
Glutamine
Systematic (IUPAC) name
(2S)-2-amino-4-carbamoyl-butanoic acid
Identifiers
CAS number	56-85-9
PubChem	738
Chemical data
Formula	C5H10N2O3
Molar mass	146.15 g/mol
SMILES	N[C@@H](CCC(N)=O)C(O)=O
Complete data

Glutamine (abbreviated as Gln or Q; Glx or Z represents either glutamine or glutamic acid) is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide formed by replacing the side-chain hydroxyl of glutamic acid with an amine functional group. It can therefore be considered the amide of the acidic amino acid glutamate. Its codons are CAA and CAG.

Nutrition

Occurrences in nature

Glutamine is the most abundant naturally occurring, non-essential amino acid in the human body. In the body it is found circulating in the blood as well as stored in the skeletal muscles. It becomes conditionally essential (requiring intake from food or supplements) in states of illness or injury. Food sources of glutamine include meat, poultry, fish, beans, eggs, and dairy products.

Functions

1) A substrate for DNA synthesis.
2) Major role in protein synthesis.
3) Promotes muscle growth and decreases muscle catabolism. ^{[citation needed]}
4) Primary source of fuel for enterocytes (cells lining the inside of the small intestine).
5) Precursor for rapidly dividing immune cells, thus aiding in immune function.
6) Regulation of acid-base balance in the kidney.^{[citation needed]}
7) Alternative source of fuel for the brain and helps to block cortisol-induced protein catabolism.
8) As a form of fixed nitogen by heterocysts, exchanged for photosynthate from undifferentiated cyanobacterial cells.

Use

In catabolic states of injury and illness, GLN becomes conditionally-essential (requring intake from food or supplements). Glutamine has been studied extensively over the past 10-15 years and has been shown to be useful in treatment of serious illnesses, injury, trauma, burns, cancer and its treatment related side-effects as well as in wound healing for postoperative patients ^{(citation pending)}. That is why it is now also classified as a "nutraceutical". Glutamine is also marketed as a supplement used for muscle growth in weightlifting, bodybuilding, endurance and other sports.

Aiding gastrointestinal function

There have been several recent studies into the effects of glutamine and what properties it possesses, and, there is now a significant body of evidence that links glutamine-enriched diets with intestinal effects; aiding maintenance of gut barrier function, intestinal cell proliferation and differentiation, as well as generally reducing septic morbidity and the symptoms of Irritable Bowel Syndrome. The reason for such "cleansing" properties is thought to stem from the fact that the intestinal extraction rate of glutamine is higher than that for other amino acids, and is therefore thought to be the most viable option when attempting to alleviate conditions relating to the gastrointestinal tract. ^[1]

These conditions were discovered after comparing plasma concentration within the gut between glutamine-enriched and non glutamine-enriched diets. However, even though glutamine is thought to have "cleansing" properties and effects, it is unknown to what extent glutamine has clinical benefits, due to the varied concentrations of glutamine in varieties of food. ^[1]

Aiding recovery after surgery

It is also known that glutamine has various effects in reducing healing time after operations. Hospital waiting times after abdominal surgery are reduced by providing parenteral nutrition regimens containing amounts of glutamine to patients. Clinical trials have revealed that patients on supplementation regimens containing glutamine have improved nitrogen balances, generation of cysteinyl-leukotrienes from polymorphonuclear neutrophil granulocytes and improved lymphocyte recovery and intestinal permeability (in postoperative patients) - in comparison to those who had no glutamine within their dietary regime; all without any side-effects. ^[3]

See also

• Bodybuilding supplements
• Dietary supplements

References

1. ^{a  b}  Boza J.J., Dangin M., Moennoz D., Montigon F., Vuichoud J., Jarret A., Pouteau E., Gremaud G., Oguey-Araymon S., Courtois D., Woupeyi A., Finot P.A. and Ballevre O. Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers. Am J Physiol Gastrointest Liver Physiol. 2001 Jul; 281(1): G267-74. PMID 11408280 Free text
2. ^a  McAnena O.J., Moore F.A., Moore E.E., Jones T.N. and Parsons P. Selective uptake of glutamine in the gastrointestinal tract: confirmation in a human study. Br J Surg. 1991 Apr; 78(4): 480-2. PMID 1903318
3. ^a  Morlion B.J., Stehle P., Wachtler P., Siedhoff H.P., Koller M., Konig W., Furst P., Puchstein C. Total parenteral nutrition with glutamine dipeptide after major abdominal surgery. Ann Surg. 1998 Feb; 227(2): 302-8. PMID 9488531
4. ^a  Jiang Z.M., Cao J.D., Zhu X.G., Zhao W.X., Yu J.C., Ma E.L., Wang X.R., Zhu M.W., Shu H., Liu Y.W. The impact of alanyl-glutamine on clinical safety, nitrogen balance, intestinal permeability, and clinical outcome in postoperative patients: a randomised, double-blind, controlled study of 120 patients. JPEN J Parenter Enteral Nutr. 1999 Sep-Oct;23(5 Suppl):S62-6. PMID 10483898

External links

• Computational Chemistry Wiki
• Nutrients and HIV: Part Three

• Supplemental uses

Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids:	The 20 Common Amino Acids	Analogues of nucleic acids:
Alanine (dp) | Arginine (dp) | Asparagine (dp) | Aspartic acid (dp) | Cysteine (dp) | Glutamic acid (dp) | Glutamine (dp) | Glycine (dp) | Histidine (dp) | Isoleucine (dp) | Leucine (dp) | Lysine (dp) | Methionine (dp) | Phenylalanine (dp) | Proline (dp) | Serine (dp) | Threonine (dp) | Tryptophan (dp) | Tyrosine (dp) | Valine (dp)

Dietary supplements
Types	Amino acids • Bodybuilding supplement • Energy drink • Energy bar • Fatty acids • Herbal Supplements • Minerals • Probiotics • Vitamins • Whole food supplements
Vitamins and minerals	Retinol (Vitamin A) • B vitamins: Thiamine (B1) • Riboflavin (B2)• Niacin (B3)• Pantothenic acid (B5)• Pyridoxine (B6)• Biotin (B7)• Folic acid (B9) • Cyanocobalamin (B12) • Ascorbic acid (Vitamin C) • Ergocalciferol and Cholecalciferol (Vitamin D) • Tocopherol (Vitamin E) • Naphthoquinone (Vitamin K) • Calcium • Choline • Chlorine • Chromium • Cobalt • Copper • Fluorine • Iodine • Iron • Magnesium • Manganese • Molybdenum • Phosphorus • Potassium • Selenium • Sodium • Sulfur • Zinc
Other common ingredients	Carnitine • Chondroitin sulfate • Cod liver oil • Copper gluconate • Creatine • Dietary fiber • Elemental calcium • Ephedra • Fish oil • Folic acid • Ginseng • Glucosamine • Glutamine • Iron supplements • Japanese Honeysuckle • Krill oil • Lactobacillus • Lingzhi • Linseed oil • Red yeast rice • Royal jelly • Saw palmetto • Spirulina • Taurine • Wheatgrass • Wolfberry • Yohimbine • Zinc gluconate
Related articles	Codex Alimentarius • Enzyte • Metabolife • Hadacol • Nutraceutical • Multivitamin

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)