Glutamine is an amino acid, one of the building blocks of protein that are
linked together by peptide bonds in specific chemical arrangements to form
proteins. It is found in both plant and animal proteins and is available in a
variety of supplemental forms. Glutamine helps the body maintain the correct
acid–alkaline balance and is a necessary part of the
synthesis of RNA and DNA. Glutamine also helps promote a healthy digestive
Unlike other amino acids that have a single nitrogen atom, glutamine contains
two nitrogen atoms that enable it to transfer nitrogen and remove ammonia from
body tissues. Glutamine readily passes the blood–brain
barrier and, within the brain, is converted to glutamic acid, which the brain
needs to function properly. It also increases gamma-aminobutyric acid (GABA) in
the brain, which is also needed for proper mental activity.
Glutamine is the most plentiful free amino acid in muscles. Its ability to
help build and maintain muscle makes glutamine especially attractive to dieters
and muscle-builders, but that same ability also helps prevent muscle-wasting
associated with prolonged inactivity, disease, and stress. With sufficient
glutamine in the bloodstream, muscle loss that would otherwise be caused by
injury, surgery, trauma, prolonged illness, or stress can be prevented. The body
uses glutamine and glucose to make glucosamine, an amino sugar that plays a key
role in the formation of nails, tendons, skin, eyes, bones, ligaments, heart
valves, and mucous secretions throughout the body.
Conditions that have been treated with L-glutamine supplements include
fibrosis, autoimmune diseases, arthritis, intestinal ailments, peptic ulcers,
diseases of the connective tissues, tissue damage caused by radiation treatment,
developmental disabilities, epilepsy, schizophrenia, fatigue, and impotence.
Because L-glutamine possibly reduces sugar and alcohol cravings, it could be
considered for treating recovering alcoholics. Suggested dose: 1,000 mg tid with
50 mg of vitamin B6, on an empty stomach.
Glutamine is found in animal proteins and vegetable proteins. Natural sources
of glutamine include soy proteins, milk, meats, raw spinach, raw parsley, and
Nutrition experts recommend choosing supplements whose label describes the
contents as USP pharmaceutical grade L-crystalline amino acids.
The purest form of amino acid supplements is called free-form and is
available in powder or encapsulated powder. Free-form amino acids are readily
absorbed and nonallergenic, and are stable at room temperature but destroyed by
high temperatures (350° to 660° F) typical of cooking.
Glutamine is available as an isolated amino acid or in combination amino acid
and protein supplements.
L-forms of amino acid supplements such as L-glutamine are believed to be more
compatible with human biochemistry than D-forms because the chemical structure
spirals to the left.
Glutamine is available in a variety of foods and food supplements, protein
mixtures, amino acid formulas, and individual supplements in liquid, powder,
tablets, and capsules. Supplemental forms of glutamine are sold in vitamin and
mineral sections of most pharmacies and health food stores.
- Glutamine is not one of the nine essential amino acids (which must be
ingested because the body cannot manufacture them). However, extreme stress and
prolonged illness may cause glutamine to become an essential amino acid, and
hence a valuable dietary component.
- Glutamine aids recovery after surgery, wounds or injury, hemorrhage,
prolonged illness including AIDS and cancer, and chemotherapy.
- In one recent study, glutamine reduced mouth pain by 4.5 days
compared to placebo users in 24 methotrexate chemotherapy patients suffering
from mouth sores and difficulty swallowing.
- Glutamine speeds healing of peptic ulcers.
- Because glutamine is one of the primary fuels used by intestinal
lining cells, supplementation with glutamine helps restore gastric mucosa and
improves mucosa metabolism. Glutamine also helps repair the gastrointestinal
lining after damage caused by radiation or leaky gut syndrome, and benefits
chronic GI diseases such as colitis, AIDS, cancer, and Crohn's disease. Large
doses (more than 1,000 mg tid) helped protect chemotherapy patients' stomach
linings, according to a 1996 study.
- Glutamine helps suppress food
|Dosage Ranges and Duration of
- Glutamine supplements, like all amino acid supplements, should be
taken on an empty stomach, preferably in the morning or between
- For peptic ulcers, 500 mg daily, taken on an empty stomach, is
- To curb food cravings, 1,000 mg daily is recommended.
- To treat irritable bowel syndrome (IBS), eliminate foods that trigger
symptoms and take glutamine (500 mg tid) and peppermint oil (1 capsule three to
six times daily).
- For stasis ulcers (open sores on the leg that are caused by poor
blood flow), take each day: glutamine (500 mg) with a basic nutritional
supplement program and vitamin C (2,000 mg in divided doses with meals and at
bedtime), vitamin A (10,000 IU), zinc (22.5 to 50 mg), and vitamin E (400 IU
orally and additional vitamin E oil squeezed from capsules onto the wound to aid
healing and prevent recurrence).
- To aid wound healing, take glutamine (500 mg) with a basic
vitamin-mineral formula and vitamin C (2,000 mg divided at meals and bedtime),
vitamin A (10,000 IU), zinc (22.5 to 50 mg), vitamin E (400 IU), and vitamin B3
(100 mg) daily.
Glutamine can worsen damage caused by any disease that allows ammonia to
accumulate to excess in the blood. It is not recommended in patients who have
Reye's syndrome, kidney disease, cirrhosis of the liver, or other illnesses that
cause overload of ammonia in the body.
Proteins (taken as a source of amino acid glutamine) should not be overused.
In healthy persons, protein is safely metabolized and broken down by the liver
into glucose and ammonia, which is a toxin. If one consumes an excessive amount
of protein or if digestion is poor or liver function is impaired, ammonia can
accumulate in the body and cause damage. Strenuous exercise can also promote
excess ammonia in the body. Too much ammonia can cause encephalopathy or hepatic
coma, or it can pose serious health threats. As ammonia is broken down by the
body into urea, the urea can cause kidney inflammation and back
- Glutamine supplements must be kept completely dry because moisture
causes glutamine powder to break down into ammonia and pyroglutamic
- Glutamine in foods is readily destroyed by cooking.
- Despite the similarity of their names, the following substances are
different and are not interchangeable: glutamine; glutamic acid, also called
glutamate; glutathione; gluten; and monosodium
In vitro, glutamine reduced the frequency of doxorubicin-induced chromosomal
aberrations (Tavares et al. 1998). In rats, treatment with glutamine before and
during doxorubicin administration diminished the cardiotoxic effects of the drug
by upregulating glutathione synthesis in the heart (Cao et al. 1999).
Clinically, treatment with glutamine (4 g bid) and doxorubicin reduced the
incidence and severity of mucositis relative to prior experience with
chemotherapy (Skubitz and Anderson 1996).
Chemotoxic effects were absent in 9 breast cancer patients treated with
glutamine (0.5 g/kg/day) during therapy with escalating doses of methotrexate
followed by doxorubicin; the median survival of participants was 35 months
(Rouse et al. 1995). Preclinical and clinical studies have demonstrated that
glutamine enhances the activity and tumor-selectivity of methotrexate therapy,
while actively protecting normal tissues. In rats, glutamine (1 gm/kg/day po)
and an intraperitoneal dose of methotrexate (20 mg/kg) increased the
concentration of the drug in tumors threefold (Rubio et al. 1998). Supplemental
glutamine also increased the therapeutic index for methotrexate by enhancing
glutathione synthesis systemically, thus improving drug tolerance while
simultaneously depleting tumor glutathione in rats (Rouse et al. 1995). In
addition, rats fed a glutamine-supplemented diet (3%) had decreased clearance
and urinary excretion of methotrexate by 25% and 65%, respectively (Charland et
Whether glutamine supplementation is beneficial during treatment with
5-fluorouracil appears to be questionable. In two placebo-controlled trials
involving several patients, oral glutamine supplementation did not have a
significant effect on 5-FU-induced mucositis (Jebb et al. 1994; Okuno et al.
1999). However, in another trial, glutamine (glycyl-L-glutamine) did reduce
indices of ulcerations in the gastric and duodenal mucosae significantly
(Decker-Baumann and Buhl 1999).
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cardiotoxicity. J Surg Res. 1999;85:178-182.
Castell LM, Newsholme EA. The effects of oral glutamine supplementation on
athletes after prolonged, exhaustive exercise. Nutrition.
Charland SL, Bartlett DL, Torosian MH. A significant methotrexate-glutamine
pharmacokinetic interaction. Nutr. 1995;11:154-158.
Decker-Baumann C, Buhl K. Reduction of chemotherapy-induced side-effects by
parenteral glutamine supplementation in patients with metastatic colorectal
cancer. Eur J Cancer. 1999;35:202-207.
Den Hond E, Hiele M, Peeters M, Ghoos Y, Rutgeerts P. Effect of long-term
oral glutamine supplements on small intestinal permeability in patients with
Crohn's disease. J Parenter Enteral Nutr. 1999;23:7-11.
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Li J, Langkamp-Henken B, Suzuki K, Stahlgren LH. Glutamine prevents
parenteral nutrition-induced increases in intestinal permeability. J Parenter
Enteral Nutr. 1994;18:303-307.
Napoli M. Chemo effect alleviated. Health Facts. October
Noyer CM, Simon D, Borczuk A, Brandt LJ, Lee MJ, Nehra V. A double-blind
placebo-controlled pilot study of glutamine therapy for abnormal intestintal
permeability in patients with AIDS. Am J Gastroenterol.
Okuno SH, Woodhouse CO, Loprinzi CL. Phase III controlled evaluation of
glutamine for decreasing stomatitis in patients receiving fluorouracil
(5-FU)-based chemotherapy. Am J Clin Oncol. 1999;22:258-261.
Rouse K, Nwokedi E, Woodliff JE, et al. Glutamine enhances selectivity of
chemotherapy through changes in glutathione metabolism. Ann Surg.
Rubio IT, Cao Y, Hutchins LF, et al. Effect of glutamine on methotrexate
efficacy and toxicity. Ann Surg. 1998;227:772-780.
Shabert JK, Wilmore DW. Glutamine deficiency as a cause of human
immunodeficiency virus wasting. Med Hypotheses. March 1996; 46:252-256.
Skubitz KM, Anderson PM. Oral glutamine to prevent chemotherapy induced
stomatitis: a pilot study. J Lab Clin Med. 1996;127:223-228.
Tavares DC, Cecchi AO, Antunes LM, et al. Protective effects of the amino
acid glutamine and of ascorbic acid against chromosomal damage induced by
doxorubicin in mammalian cells. Teratog Carcinog Mutagen.
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Copyright © 2000 Integrative Medicine
CommunicationsThis publication contains
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