The science and art of nutritional assessment Khursheed Jeejeebhoy Gastroenterology Division, St Michael’s Hospital, Toronto, Ontario, Canada INTRODUCTION Nutritional health is maintained by a state of equilibrium in which nutrient intake and requirements are in balance. Malnutrition occurs when net nutrient intakes (nutrient intake corrected for abnormally large faecal or urinary losses) is less than requirements. Malnutrition leads to a succession of metabolic abnormalities, physiological changes, reduced organ and tissue function, and loss of body mass. In order for Nutritional Assessment to be clinically useful it is necessary to examine each of the proposed methods by asking the following questions: Does the method specifically assess the risk of morbidity and mortality resulting from malnutrition? Does it identify and separate the causes and consequences of malnutrition and disease in the individual patient? Can the technique determine whether the patient will clinically benefit from nutritional support? In this presentation these questions will be evaluated for the following nutritional assessment techniques: TRADITIONAL NUTRITIONAL ASSESSMENT INDICES. Nutritional status has been traditionally defined by body composition, plasma protein concentrations, immune competence and multivariate analysis. BEDSIDE CLINICAL ASSESSMENT–SUBJECTIVE GLOBAL ASSESSMENT. A clinical method for evaluating nutritional status, termed subjective global assessment (SGA), encompasses historical, symptomatic, and physical parameters. MEASUREMENT OF BODY COMPOSITION. The body consists of compartments or components. There are over thirty five well recognized components and these are organized into five levels of increasing complexity, atomic, molecular, cellular, tissue system, and whole body. FUNCTIONAL TESTS OF MALNUTRITION. Functional impairment in malnutrition has been previously studied by examining changes in immune function, ability to perform work in an ergometer and in changes of heart rate during maximal exercise. CONCLUSION Malnutrition is a continuum which starts when the patient fails to eat enough to meet needs and progresses through a series of functional changes which precede any changes in body composition which are related to the duration of reduced intake and its severity. To base the definition of malnutrition on any one of these changes is inappropriate. Only by recognizing the different facets of malnutrition can we define its various manifestations in relation to our clinical objectives.   From PENSA 2009 “Energizing Nutrition Support Practice for Life” June 5-7 2009, Shangri-La Hotel, Kuala Lumpur, Malaysia Page: 26