Nutrition and gut immunity

Area of Science:

• Gastroenterology and Immunology

Background:

• The human intestine harbors a vast population of nonpathogenic bacteria, crucial for host and microbial survival.
• Critical illness, characterized by acidosis, gut starvation, antibiotics, and compromised mucosal defenses, creates vulnerability.
• This environment threatens both the host and the resident bacterial populations.

Purpose of the Study:

• To review the changes in host immunologic defenses during critical illness.
• To examine how altered oral or enteral intake impacts these defenses.
• To understand the consequences of mucosal injury on host-microbial interactions.

Main Methods:

• Literature review of studies on critical illness, gut microbiome, and host immunity.
• Analysis of mechanisms underlying altered immune responses.
• Examination of the role of nutritional intake and mucosal integrity.

Main Results:

• Critical illness significantly alters the gut environment and host defenses.
• Reduced oral or enteral intake exacerbates immune dysregulation.
• Breakdown of mucosal barriers increases susceptibility to bacterial translocation.

Conclusions:

• Altered nutritional status and mucosal integrity during critical illness profoundly impact innate and adaptive immunity.
• Understanding these immunologic shifts is vital for managing critically ill patients.
• Further research is needed to develop targeted interventions.