Although clinical nutrition is a frequently used intervention in inpatient care, high quality trials proving its effectiveness and safety when used in the acutely-ill polymorbid medical inpatient population are largely lacking. From an evolutionary perspective, illness-related low appetite is protective and part of the host response to improve recovery from disease. Large and well performed trials in the intensive care setting have shown deleterious effects of (parenteral) feeding strategies aiming at higher caloric intakes compared to lower intakes, raising the question of whether feeding per se may be simply maladaptive in acute severe illness. Outside critical care, similar large-scale studies are lacking with basic clinical questions regarding the optimal amount/composition of nutrition and best patient selection remaining largely unanswered. Also, the interplay of nutritional interventions and its influence on the microbiome remains largely unclear. Given the magnitude of morbidity caused by malnutrition and the high number of affected patients, it is surprising how little the medical community has invested in better understanding ways to improve this condition. It is now time to perform high-quality trials to better understand how to best deal with this condition in the acute care setting. Such trials will allow change from a one-size-fits-all approach, to more evidence-based, personalized nutritional interventions, ultimately improving patient outcomes. While there is ongoing discussion about definition of malnutrition, we should rather focus on the identification of patients who do or do not benefit from nutritional interventions.
Keywords: Acute illness; Inflammation; Malnutrition; Nutrition.