Glutamine: benefits, dosage, contraindications
Scientific name(s)
L-glutamine
Family or group:
Amino acids
Indications
Scoring methodology
EFSA approval.
Sickle cell disease ✪✪✪✪✪
Oxidative stress contributes to the effects of sickle cell disease. Glutamine has an antioxidant effect by increasing the reduced proportion of nicotinamide adenine dinucleotide (NAD) in sickled erythrocytes (NAD functions as an electron carrier in redox reactions; the reduced form acts as a reductant). The administration of glutamine powder is approved in some countries (the United States Food and Drug Administration) to reduce acute complications of sickle cell disease in adults and children aged 5 years and older. Taking 5 to 15 grams (0.3 gram/kg of body weight) orally twice daily for 48 weeks in patients with sickle cell disease aged 5 years and older, with or without hydroxycarbamide, reduces the frequency of painful crises by 25% to 30%, the incidence of acute chest syndrome by 15%, the number of hospitalizations by 33%, and the number of days of hospitalization by 40% compared with placebo.
Posologie
Oral
5 - 15 g
48 - weeks
Adults, Children
powder
Burns ✪✪✪✪✪
Some clinical research shows that the administration of enteral nutrition in combination with glutamine at a rate of 0.35 to 0.5 grams/kg per day for 12 to 14 days, 24 to 48 hours after hospitalization for severe burns (excluding inhalation burns), reduces hospital length of stay by 6 to 9 days and may shorten wound healing compared with control enteral nutrition. Other clinical research shows that the administration of enteral nutrition supplemented with 4.3 grams of glutamine every 4 hours starting 24 hours after a burn reduces the risk of mortality by 83% and the risk of Pseudomonas infections in cases of severe burns (including inhalation burns).
Posologie
Oral
0.35 - 0.5 g/kg
14 - days
powder
Reduction of mortality and infectious morbidity in adult burn patients receiving enteral glutamine supplements: a prospective, controlled, randomized clinical trial.
The effect of supplemental enteral glutamine on plasma levels, intestinal function, and outcome in severe burns: a randomized, double-blind, controlled clinical trial.
A meta-analysis of trials using the intention to treat principle for glutamine supplementation in critically ill patients with burn.
HIV infection ✪✪✪✪✪
Oral glutamine appears to improve intestinal absorption of nutrients, decrease intestinal permeability, and increase weight gain in people with AIDS. Doses of 40 grams per day appear to have the greatest effect. Lower doses (14 grams per day for 8 weeks) may also be effective when used in combination with arginine and beta-hydroxy beta-methylbutyrate (a metabolite of leucine).nnIn addition, clinical research shows that oral glutamine at 30 grams per day for 10 days reduces the severity of nelfinavir-associated diarrhea (an antiretroviral) compared with placebo in HIV-infected patients.nn
Posologie
Oral
14 - 40 g
8 - weeks
powder
Synergies
A double-blind placebo-controlled pilot study of glutamine therapy for abnormal intestinal permeability in patients with AIDS.
Nutritional treatment for acquired immunodeficiency virus-associated wasting using beta-hydroxy beta-methylbutyrate, glutamine, and arginine: a randomized, double-blind, placebo-controlled study.
Recovery ✪✪✪✪✪
Several clinical studies have evaluated the effect of glutamine on the risk of infectious complications in critically ill patients. Some studies show that glutamine reduces the risk of infectious complications in multiple-trauma or surgical patients. Analyses of these clinical trials and others suggest that glutamine supplementation reduces the risk of nosocomial infections in critically ill patients by 15% to 18%. Enteral nutrition supplemented with glutamine at 20 g/day or 0.2 to 0.6 grams/kg/day has been used. As a rule, glutamine-enriched enteral nutrition is administered for at least 5 days.
Posologie
Oral
20 g
5 - days
powder
Metabolic and immune effects of dietary arginine, glutamine and omega-3 fatty acids supplementation in immunocompromised patients.
Total parenteral nutrition supplemented with the dipeptide L-alanyl-L-glutamine reduces infectious complications and glucose intolerance in critically ill patients: the multicenter, randomized, double-blind, controlled study conducted in France.
Randomized study of clinical outcomes in critically ill patients receiving glutamine-supplemented enteral nutrition.
Effects of glutamine-supplemented diets on intestinal immunology.
Randomized trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma.
Obesity ✪✪✪✪✪
A clinical study in six obese women shows that taking 0.5 g/kg of glutamine per day for 4 weeks reduced body weight by 2.8 kg and waist circumference by 3.8 cm compared with baseline but did not improve glycemic indices. nnAnother clinical trial in 36 overweight and obese patients shows that taking 30 g of glutamine per day for 2 weeks reduced waist circumference by 1.8 cm but did not improve body weight, body mass index (BMI) or glycemic indices compared with baseline. Given the small size of the studies, the short duration of treatment and conflicting results, the long-term effects of glutamine on body weight, waist circumference and glycemic indices in these patients are unclear.nn
Posologie
Oral
0.5 g/kg
4 - weeks
powder
Skin healing ✪✪✪✪✪
Preliminary research shows that daily intake of 20 grams of oral glutamine in combination with 500 mg of ascorbic acid, 166 mg of vitamin E, 3.2 mg of beta-carotene, 100 µg of selenium and 6.6 mg of zinc for 14 days in traumatized patients suffering from healing disorders reduced wound closure time by 29 days compared with placebo.nn
Posologie
Oral
20 g
14 - days
powder
Synergies
Irritable bowel syndrome ✪✪✪✪✪
Clinical research in patients with postinfectious irritable bowel syndrome with predominant diarrhea shows that taking glutamine at 5 g three times a day for 8 weeks leads to an improvement in symptoms with a reduction in the number of bowel movements per day compared with placebo. Glutamine intake also appears to reduce abdominal pain and improve quality of life.
Posologie
Oral
15 g
8 weeks
powder
Acid-base balance ✪✪✪✪✪
The use of glutamine as a nitrogen carrier is important for the excretion of nitrogenous wastes and the maintenance of acid-base balance. The kidney uses glutaminase to hydrolyze glutamine and generate ammonia, which is then excreted in the urine. The availability of ammonia facilitates the excretion of acid loads. In cases of acidosis, glutamine consumption and glutaminase activity are both increased in the kidney.
Posologie
Oral
14 g
powder
Properties
Digestive effect
The gastrointestinal tract is one of the largest users of glutamine in the body. Some data suggest that glutamine plays a regulatory role in the intestine, affecting cell proliferation and differentiation. Glutamine depletion can lead to atrophy, ulceration, and necrosis of the intestinal epithelium. nnIn an in vivo animal study, glutamine deficiency produced diarrhea, villous atrophy, mucosal ulcerations, and intestinal necrosis.nnIn patients suffering from diarrhea, glutamine appears to increase water and electrolyte absorption, reduce water and sodium loss in the intestine, and improve intestinal permeability.nn
Usages associés
Immunomodulator
Glutamine can improve the function of stimulated immune cells. It appears to affect lymphocyte proliferation, cytokine production, bacterial killing by neutrophils, and the phagocytic and secretory activities of macrophages.nnOn the other hand, decreased glutamine concentrations after surgery appear to impair neutrophil and monocyte function, which may increase the risk of infection. Parenteral glutamine after surgery appears to improve lymphocyte count and function in some patients.nn
Usages associés
Essential
Glutamine has various biological roles, notably acting as a carrier of nitrogen between tissues alongside alanine, acting as a precursor to the antioxidant glutathione, acting as a precursor of nucleotides, regulating acid–base metabolism and being involved as a substrate in gluconeogenesis. It can also stimulate the production of L-citrulline and L-glycine by acting as a substrate.
Usages associés
Wound healing
After an injury, about one third of the nitrogen mobilized for wound repair and the function of vital organs comes from glutamine. In human research, a combination of glutamine, arginine, and beta-hydroxy-beta-methylbutyrate increased collagen synthesis.
Usages associés
Bioenergetic
The oxidation of glutamine can generate adenosine triphosphate (ATP) for cellular respiration. In fact, glutamine serves as a primary respiratory fuel in certain cells such as enterocytes and lymphocytes. The total amount of cellular energy derived from glutamine depends on the degree of oxidation and the rate of glutamine utilization. These factors, in turn, largely depend on the relative proportions of available glutamine and glucose as well as the cell type.
Musculoskeletal effects
During physical stress, the body consumes more glutamine than skeletal muscles can produce. Progressive muscle breakdown can occur when the body tries to meet glutamine needs. Protein sparing occurs when sufficient protein and amino acids are provided to prevent muscle breakdown.nnAlthough glutamine is often used for muscle development, preliminary research suggests that glutamine does not affect muscle precursor cells, which would be responsible for muscle hypertrophy.nn
Antioxidant
There is substantial evidence suggesting that glutamine plays a key role in regulating the synthesis of glutathione, a powerful antioxidant. As a source of glutamate, glutamine provides one of the constituents of glutathione, but glutamine can also contribute to glutathione synthesis indirectly by exchanging intracellular glutamate (derived from glutamine) across the cell membrane for extracellular cysteine, another component of glutathione.nn
Usages associés
Neurological
Disruptions of glutamine metabolism and/or transport may contribute to alterations in glutamatergic or GABAergic transmission that are associated with various pathological conditions in the brain, such as epilepsy and hepatic encephalopathy. Glutamine appears to affect neurotransmission by interacting with N-methyl-D-aspartate (NMDA) receptors (they are ionotropic receptors activated under physiological conditions by glutamate and glycine that are essential for memory and synaptic plasticity).nn
Safe dosage
Adults 18 years and older: 14 g (powder)
Glutamine is taken as a supplement at a dose of 14 g/day (above dietary intake), safely and without adverse effects. Moreover, glutamine has been used safely in clinical research at doses up to 40 g per day or 1 g/kg per day.
Children aged 1 to 18 years: 700 mg/kg (powder)
Glutamine has been used in clinical research at a dose not exceeding 0.7 g/kg per day in children aged 1 to 18 years.
Interactions
Médicaments
Anticonvulsants: moderate interaction
Glutamine is metabolized to glutamate, an excitatory neurotransmitter, which could theoretically reduce the effects of anticonvulsant medications.
Lactulose: moderate interaction
Theoretically, glutamine is metabolized to ammonia, which may interfere with lactulose's ammonia-lowering effects.
Precautions
Pregnant women: avoid
Avoid use due to lack of reliable and sufficient information.
Breastfeeding women: avoid
Avoid use due to lack of reliable and sufficient information.
Contraindications
Cirrhosis: contraindicated
In cirrhotic patients, oral glutamine increases serum ammonia levels.
Hepatic encephalopathy: contraindicated
Theoretically, glutamine, which is metabolized to ammonia, could worsen hepatic encephalopathy.
Epilepsy: contraindicated
Theoretically, excessive amounts of glutamine and its metabolite, glutamate, could lower the seizure threshold.
Cancer: contraindicated
Glutamine metabolism is part of the cellular processes that regulate tumor progression and treatment responsiveness in a number of cancers, notably melanoma and breast cancer. Some types of cancer are highly dependent on glutamine because it provides energy, carbon, and nitrogen, all of which contribute to tumor growth and survival.
