Malnutrition and undernutrition John Saunders Trevor Smith Mike Stroud Abstract The term malnutrition is used to describe a deficiency, excess or imbal- ance of a wide range of nutrients, resulting in measurable adverse effects on body composition, function and clinical outcome. 1 As such it can refer to individuals who are either over- or under-nourished although it is frequently used synonymously with undernutrition, as is the case in this article. Although it is well known that malnutrition is common in the developing world, the fact that significant malnourishment occurs in UK society and health settings is not widely appreciated. Malnutrition occurs for psychosocial reasons and as a consequence of disease. It has direct effects on clinical outcomes and is associated with massive health- care expenditure. Recognition and treatment can have a significant impact on patient care and can reduce costs. Failure to diagnose and manage carries medico-legal risks. It is the responsibility of all doctors to recognize the fundamental importance of proper nutritional care to good clinical practice. 2 The focus of this article is predominantly con- cerned with malnutrition and its consequences in the UK. Keywords clinical outcome; health economics; malnutrition; MUST score; re-feeding syndrome; screening The term malnutrition is used to describe a deficiency, excess or imbalance of a wide range of nutrients, resulting in measurable adverse effects on body composition, function and clinical outcome. 1 It is the responsibility of all doctors to recognize the importance of proper nutritional care to good clinical practice. 2 Worldwide, more than 3.5 million mothers and children under 5 die unnecessarily each year owing to malnutrition, 3 and around 178 million children have stunted growth. Micronutrient defi- ciencies affect huge numbers; iodine deficiency alone is thought to affect about 2 billion people. In the UK, malnutrition remains an under-recognized problem facing patients, clinicians and the wider society. It is not only very common in hospital and institutional care settings but is widespread in the community. It is both a consequence and a cause of disease. Approximately 2% of the UK population are underweight e defined as a body mass index (BMI) below 18.5 kg/m 2 e but this is an underestimate of malnutrition, since those who unintentionally lose weight from a position of relative excess may also be at risk what- ever their BMI. The prevalence of malnutrition in the free-living elderly or those with chronic diseases increases at least two-fold and individuals in institutional care have a prevalence of malnutrition between 30 and 42%. 4 UK hospital patients with malnutrition are particularly likely to be malnourished for reasons summarized in Table 1. In a large national survey conducted in 2008, 28% of patients admitted in hospital were at risk as indicated by a high score on the MUST screening tool. The prevalence was particularly high in specific sub-populations (e.g. 34% of all emergency admissions and 52% of admissions from care What’s new? C NICE guidance on nutrition support in adults C Detailed nationwide BAPEN survey assessing nutritional status of hospital admissions revealed the extent of the problem C The high estimated financial cost of malnutrition has focused political attention on addressing the problem of malnutrition C Objectives for Nutrition in Undergraduate Medical Training (ICGN/Academy of Royal Medical Colleges) Causes of malnutrition and further deterioration in nutritional status among hospital in-patients Medical causes of inadequate and/or poor’quality oral intake C Anorexia of disease C Nausea and vomiting C Gastrointestinal dysfunction C Reduced absorption of macro- and/or micro-nutrients C Increased nutrient loses C ‘Nil by mouth’ for investigation or medical reasons C Physical disability and inability to feed self Environmental causes of inadequate and/or poor’ quality oral intake C Inadequate food quality C Inadequate food availability C No protected meal times C Inadequate training and knowledge of medical and nursing staff Altered requirements C In critical illness there are altered substrate demands and several sub-groups of patients have a increased energy expenditure (see below) Table 1 John Saunders MRCP is a Research Fellow in Clinical Nutrition at the Institute of Human Nutrition and a Specialist Registrar in Gastroenterology at Southampton University Hospital, Southampton, UK. Competing interests: none declared. Trevor Smith MRCP is a Consultant in Clinical Nutrition and Gastroenterology at the Institute of Human Nutrition and Southampton University Hospital, Southampton, UK. Competing interests: none declared. Mike Stroud BSc MD DSci FRCP is a Consultant Gastroenterologist and Senior Lecturer in Medicine and Nutrition at the Institute of Human Nutrition and Southampton University Hospital, Southampton, UK. Competing interests: none declared. UNDERNUTRITION AND CLINICAL NUTRITION MEDICINE 39:1 45 Ó 2010 Elsevier Ltd. All rights reserved.