Glutamine

What is glutamine?

Glutamine is a conditionally essential amino acid, which can be produced in your body from another amino acid glutamic acid and ammonia, but in increased body demands, such as in heavy exercise, injury, burns, chronic illness or cancer you might need to obtain additional amounts from foods in order to be healthy ^[1]. Glutamine is produced mainly in the muscles and consumed by the gastrointestinal and kidney cells ^[4].

In foods, glutamine is incorporated into proteins.

Glutamine abbreviation (symbol): Gln

Glutamine Functions in the Human Body

Glutamine is ^[2,5]:

• A building block of proteins
• A glucogenic amino acid — it can be converted into glucose
• An energy source for the intestinal, kidney and nerve cells
• The main nitrogen carrier
• A precursor for the excitatory neurotransmitter glutamate and for the inhibitory neurotransmitter GABA.
• A buffer – it affects the acid-base balance in the blood

Foods High in Glutamine

• ANIMAL FOODS: meat, fish, cheese
• PLANT FOODS: legumes

Foods low in glutamine: fruits, vegetables

Glutamine Supplements

Nonprescription (over-the-counter) oral L-glutamine supplements are available as tablets or powders. Prescription oral supplements and intravenous injections are also available.

Glutamine Health Benefits

Glutamine supplements are POSSIBLY EFFECTIVE for:

• Prevention of weight loss and relieving intestinal problems in individuals with HIV/AIDS ^[3,17]
• Replenishment of the liver glycogen stores after exercise, when ingested along with carbohydrates ^[4,18]

There is CONFLICTING EVIDENCE about the effect of intravenous or enteral (via intestinal tube) glutamine supplements in the prevention or treatment of infections and other complications in critically ill patients ^{[8,10,11,13,15,16]} or in improvement of symptoms in acute pancreatitis ^[3,12,14].

Glutamine supplements are POSSIBLY INEFFECTIVE ^[3] in the prevention or treatment of Crohn’s disease, cystinuria, or in improving athletic performance or rehydration in infants with severe diarrhea.

There is INSUFFICIENT EVIDENCE ^[3] about the effectiveness of glutamine supplements in the prevention or treatment of alcoholism or alcohol withdrawal, anxiety, attention deficit-hyperactivity disorder (ADHD), depression, diarrhea, exercise-induced fatigue ^[19], insomnia, irritability, low birth weight, muscle and joint pains caused by the drug paclitaxel (used to treat cancer), nerve pain, short bowel syndrome, sickle cell anemia, muscular dystrophy or soreness in the mouth caused by chemotherapy ^[7,9], stomach ulcers or ulcerative colitis, or in improving immunity during chemotherapy or promoting protein synthesis (muscle mass) ^[19].

Glutamine Safety: Side Effects, Toxicity

Glutamine is POSSIBLY SAFE for most adults when taken in doses up to 40 g daily or as intravenous injection in doses up to 600 mg/kg body weight daily ^[3].

Side effects may include nausea, vomiting, stomach pain, gas, dry mouth, runny nose, swelling of hands or feet, muscle or joint pain, headache, dizziness, tiredness, rash, itch, increased sweating; allergic reactions to glutamine are possible ^[5].

Who should not take glutamine supplements?

Pregnant and breastfeeding women ^[5], patients with hepatic encephalopaty, individuals allergic to monosodium glutamate (MSG) and patients with mania or seizures should avoid glutamine ^[3].

Glutamine-Drug Interactions

Glutamine may decrease the effectiveness of lactulose, and anticonvulsants, such as phenobarbital, primidone, valproic acid, carbamazepine, phenytoin ^[3].