Malnutrition-Sarcopenia Syndrome in older adults: Causes, consequences, and countermeasures.

Whether the Malnutrition-Sarcopenia Syndrome (MSS) represents a distinct clinical entity or simply describes severe malnutrition with prominent muscle wasting remains debated. Nevertheless, the coexistence of inadequate nutritional status and severe loss of skeletal muscle mass, strength, and function creates clinically significant challenges that warrant focused attention. The causes of MSS involve a vicious cycle driven by insufficient dietary intake, inflammation, hormone deficiency as well as physical inactivity. In a bidirectional relationship, malnutrition accelerates muscle protein breakdown and impairs synthesis, while sarcopenia reduces functional capacity and potentially leads to decreased physical activity and loss of independence. The consequences are substantial and include accelerated functional decline and delayed convalescence, reflected by prolonged hospital length of stay and higher rates of increased mortality compared to single conditions. Effective countermeasures require integrated interventions addressing both components simultaneously: adequate protein and energy intake, and vitamin D, combined with progressive resistance training, treatment of underlying diseases, and medication optimization. This multidisciplinary approach demonstrates synergistic benefits that exceed addressing either condition alone. Regardless of whether MSS constitutes a unique syndrome, recognizing this clinical pattern serves the pragmatic purpose of identifying vulnerable older adults who require comprehensive, simultaneous nutritional and functional interventions to break the vicious cycle and improve outcomes. See also the graphical abstract(Fig. 1).