Good nutrition is essential to regulate the body’s cell growth and repair. Carbohydrates, lipids and proteins (providing energy) and vitamins and minerals (catalysing metabolic reactions) are all essential nutrients, together with water. Sufficient intake of these can be achieved by consuming a healthy diet composed of largely starches, vegetables and fruit, with smaller portions of proteins and dairy and even smaller amounts of fats and simple sugars. Together these substances will provide the daily calorific requirements, currently estimated to be 2500 kcal for an adult male and 2000 kcal for an adult female.¹

NICE (2012) defines malnutrition as ‘a state in which a deficiency of nutrients such as energy, protein, vitamins or minerals results in measurable adverse effects on body composition, function or clinical outcome’.² All individuals with a suboptimal diet are at risk, particularly those who are elderly with a reduced appetite, or who are unable to acquire and prepare food for themselves. Members of certain ethnic and subcultural groups may not eat all the recommended food types, thus predisposing them to malnutrition unless careful dietary adjustments are made. In acute and critical illness significant nutritional problems may occur. Firstly, the body experiences metabolic stress, especially with pyrexia, and this leads to increased energy expenditure and demand. Secondly, with hypoperfusion the cells are deprived of their normal energy sources and this leads to anaerobic metabolism and the production of lactic acid. This acidity creates a hostile environment for cells further impairing their growth, function and repair.³