Which form of glutamine supplementation is most beneficial?

• A. Enteral
• B. Parenteral
• C. Both
• D. None

Answer: (B)

Glutamine becomes conditionally essential in severe illness, and delivering enough to support immune cells and gut lining is crucial. When nutrition support is needed, delivering glutamine intravenously provides a reliable, direct supply that bypasses gut absorption issues. The parenteral route, usually given as the alanyl-glutamine dipeptide, is favored because it is more stable in parenteral solutions and is efficiently utilized by cells, ensuring consistent plasma levels to immune cells, enterocytes, and other rapidly dividing tissues. Enteral glutamine can help when the gut is functioning and feeding tolerance is good, but in many critically ill or PN-requiring patients, the parenteral form offers more dependable delivery and potential benefit.