Nutrition interventions and post–intensive care syndrome: A narrative review

Growing attention has been directed toward the long-term consequences of critical illness, particularly the physical, cognitive, and psychological impairments following intensive care unit (ICU) discharge. At the core of the physical domain lies ICU-acquired weakness (ICU-AW). ICU-AW is driven by systemic inflammation, prolonged catabolism, malnutrition, and immobility. The resultant sustained muscle loss significantly impairs recovery and causes loss of independence, reduced quality of life, and increased mortality. Malnutrition-either preexisting or acquired in the ICU-is a major determinant of recovery, yet nutrition management remains challenging because of the risks of both overfeeding and underfeeding. Compounding this is the lack of robust biomarkers to guide individualized nutrition strategies. Current evidence supports illness phase-specific, personalized nutrition, starting with hypocaloric feeding during the acute phase of critical illness and progressing to higher-energy, protein-rich support during recovery. Recent studies caution against excessive early protein provision, which may suppress autophagy and induce metabolic stress. Monitoring tools such as indirect calorimetry and body composition analysis may guide tailored interventions. Additionally, immunonutrients, anabolic agents, and early rehabilitation show promise as adjunctive strategies, although further high-quality trials are needed to define their role and risk-to-benefit ratio. This narrative review examines the pathophysiology of muscle wasting during critical illness; reviews recent data addressing the central role of nutrition in modulating outcomes, including post-intensive care syndrome; and reviews recent developments that are improving our understanding of nutrition, biomarkers, and individualized nutrition and nutrition adjuncts.