Glutamine supplementation in the newborn infant

Area of Science:

• Biochemistry
• Nutrition
• Critical Care Medicine

Background:

• Glutamine is a non-essential amino acid synthesized from glutamate.
• Its metabolism is compartmentalized, with oral glutamine primarily metabolized in splanchnic tissues.
• Plasma glutamine levels decrease during acute stress and illness, leading to its classification as conditionally essential.

Purpose of the Study:

• To review clinical trials on glutamine supplementation in parenteral and enteral nutrition.
• To evaluate the impact of glutamine on various clinical outcomes, from acute effects to mortality and infection risk.
• To discuss the reasons behind the observed differences in trial outcomes, particularly in low birth weight (LBW) infants.

Main Methods:

• Review of clinical trials investigating glutamine supplementation.
• Analysis of outcome measures including acute physiological effects, protein metabolism, immune system activation, mortality, and nosocomial infections.
• Discussion of findings in adult and pediatric populations, with a focus on LBW infants.

Main Results:

• Acute studies in LBW babies showed some benefits, such as altered protein metabolism and immune system activation.
• These acute benefits did not translate into significant reductions in mortality or nosocomial infections.
• Glutamine's instability in solution limits its routine addition to parenteral nutrition mixtures.

Conclusions:

• While glutamine plays vital physiological roles and shows acute benefits in some critical illness contexts, its supplementation does not consistently improve long-term clinical outcomes like mortality or infection rates in LBW infants.
• The compartmentalized metabolism and potential instability of glutamine present challenges for effective supplementation.
• Further investigation is required to elucidate the precise role and optimal application of glutamine in critically ill populations.