The scientific basis of immunonutrition

Area of Science:

• Clinical Nutrition
• Immunology
• Critical Care Medicine

Background:

• Immune-modulating substrates, found in macro- and micronutrients, are increasingly studied for their clinical impact.
• Enteral formulas enriched with specific immune-modulating nutrients are available for clinical use.

Purpose of the Study:

• To review the scientific rationale behind enteral immunonutrition.
• To examine the effects of immune-modulating nutrients on mucosal barrier, cellular defense, and inflammatory responses.

Main Methods:

• Review of scientific literature on enteral immunonutrition.
• Analysis of mucosal barrier structure and function.
• Evaluation of cellular defense mechanisms.
• Assessment of local and systemic inflammatory responses.

Main Results:

• Critical illness impairs mucosal barrier and cellular defense, making enteral immunonutrition potentially beneficial.
• Meta-analyses suggest reduced infection risk, shorter ventilator and hospital stays with enteral immunonutrition.
• Benefits are observed in malnourished patients tolerating adequate formula amounts.
• No benefit or potential harm reported in severe sepsis, shock, or organ failure.

Conclusions:

• Enteral immunonutrition has a Grade A recommendation for clinical use, particularly in malnourished patients.
• Immune-enhancing substrates may exacerbate systemic inflammation in severe sepsis, requiring caution.
• Further research is needed to optimize immunonutrition strategies for different critical illness states.