Glutamin

Glutamin, or L-glutamine, is one of the twenty standard amino acids. It is a polar, nonessential amino acid that becomes conditionally essential under stress, illness, or injury when the body's capacity to synthesize it may be insufficient.

Chemical and biological characteristics: Glutamine is the amide of glutamic acid. In the body, it exists mainly in its L-form and participates in multiple metabolic pathways, including serving as a key nitrogen donor and as a precursor for the synthesis of nucleotides, glutathione, and other amino acids. In the brain, glutamine forms part of the glutamate–glutamine cycle, linking neurotransmitter metabolism with astrocytes and neurons.

Metabolism and function: Glutamine is synthesized from glutamate by the enzyme glutamine synthetase, primarily in muscle and other tissues. It is transported in the bloodstream to various organs and can be deaminated back to glutamate by glutaminase as needed. In the kidneys, glutamine metabolism contributes to ammonium production for acid–base balance. It also serves as an energy source for rapidly dividing cells, including enterocytes and immune cells.

Dietary sources and supplementation: Glutamine is abundant in protein-rich foods such as meat, fish, eggs, dairy products, legumes, and grains. It is also available as a free amino acid supplement and is used in some medical nutrition formulations, particularly for patients with critical illness or gastrointestinal disorders.

Clinical relevance: In clinical settings, glutamine supplementation has been studied for gut integrity, immune function, and recovery after trauma or surgery. Evidence of benefit varies by patient population and condition; it is generally considered safe at recommended doses, though caution is advised in severe liver disease and certain kidney conditions.