Effects of nutritional therapy on morphofunctional outcomes in critically ill patients: A systematic narrative...

Morphofunctional deterioration, resulting from muscle depletion, accompanied by reduced strength and functional impairment, limits the autonomy and quality of life of patients surviving critical illness. However, studies exploring the impact of nutritional therapy on the morphofunctional trajectory of critically ill patients during and after Intensive Care Unit (ICU) admission are still scarce.

To synthesize and critically discuss the available evidence on the effects of nutritional therapy on morphofunctional outcomes in critically ill adult ICU patients, delineating the state of the art on the topic and highlighting current methodological gaps and limitations in the literature.

This is a literature review, conducted through systematic searches in major databases and grey literature. Primary studies published between 2015 and 2025 that evaluated nutritional interventions on muscle mass, strength, and/or physical function were included. Studies that combined non-nutritional interventions were excluded.

Twenty-nine studies were included. High-protein strategies concentrate the greatest proportion of positive effects, especially on muscle mass, with variable repercussions on strength and limited effects on physical function. Supplementation with β-hydroxy-β-methyl butyrate and adequate nutritional intake also showed a predominance of favorable effects, especially in structural outcomes. In contrast, interventions such as high-calorie nutrition, isolated amino acid supplementation, intermittent enteral feeding, early initiation of enteral nutrition, and the use of symbiotics mostly demonstrated no effect. Muscle mass was the most investigated parameter, with consistently favorable results. Although less evaluated, muscle strength showed the highest proportion of positive responses, especially when associated with concomitant effects on muscle mass. Physical function showed less responsiveness to interventions. Only eight studies evaluated more than one morphofunctional parameter, and only three investigated muscle mass, strength, and function in an integrated manner.

Nutritional therapy impacts the morphofunctional parameters of critically ill patients by preserving structural integrity, with conditional repercussions on strength, while functional recovery requires multimodal approaches. The need for studies that evaluate these parameters in an integrated manner is highlighted, as well as the inclusion and contextualization of longitudinal follow-up that extends beyond the ICU.