Which statement about glutamine supplementation is true?

Which statement about glutamine supplementation is true?

• A. Parenteral supplementation is more beneficial than enteral because enteral glutamine is protein bound and content is hard to determine
• B. Enteral supplementation is more beneficial than parenteral
• C. Glutamine has no effect
• D. Dipeptide glutamine is never used in PN

Answer: (A)

In delivering glutamine, stability and how much actually reaches systemic circulation matter. Free glutamine is unstable in parenteral nutrition solutions and is rapidly degraded, so it’s given as a dipeptide (usually alanyl-glutamine) in PN. This dipeptide is stable in the IV mix, is efficiently hydrolyzed to glutamine in tissues, and provides a more reliable rise in systemic glutamine levels, which supports immune function and nitrogen balance in stressed patients. Enteral glutamine, while it can help the gut, is largely utilized by enterocytes and first-pass metabolism means less reaches the systemic circulation. The exact amount of free glutamine available from enteral sources can be hard to quantify because much of it is linked within dietary protein and varies with formula composition. That makes systemic delivery less predictable than parenteral dipeptide glutamine. Therefore, parenteral supplementation with a dipeptide form tends to be more beneficial for ensuring adequate systemic glutamine in patients receiving PN. The idea that dipeptide glutamine isn’t used in PN or that enteral glutamine is clearly superior isn’t supported by evidence.

In delivering glutamine, stability and how much actually reaches systemic circulation matter. Free glutamine is unstable in parenteral nutrition solutions and is rapidly degraded, so it’s given as a dipeptide (usually alanyl-glutamine) in PN. This dipeptide is stable in the IV mix, is efficiently hydrolyzed to glutamine in tissues, and provides a more reliable rise in systemic glutamine levels, which supports immune function and nitrogen balance in stressed patients.

Enteral glutamine, while it can help the gut, is largely utilized by enterocytes and first-pass metabolism means less reaches the systemic circulation. The exact amount of free glutamine available from enteral sources can be hard to quantify because much of it is linked within dietary protein and varies with formula composition. That makes systemic delivery less predictable than parenteral dipeptide glutamine.

Therefore, parenteral supplementation with a dipeptide form tends to be more beneficial for ensuring adequate systemic glutamine in patients receiving PN. The idea that dipeptide glutamine isn’t used in PN or that enteral glutamine is clearly superior isn’t supported by evidence.