(BQ) Part 2 book “Clinical biochemistry & metabolic medicine” has contents: Vitamins, trace elements and metals, the gastrointestinal tract, liver disorders and gallstones, cardiovascular disease, clinical biochemistry at the extremes of age, patient sample collection and use of the laboratory, and other contents. | 14 Nutrition Starvation Trauma and sepsis Nutritional assessment 216 217 217 This chapter gives an outline of certain nutritional abnormalities and how they overlap with aspects of chemical pathology. It is not, however, a substitute for a nutrition textbook. The reader may also find Chapters 12 and 13 (on carbohydrate and lipid disorders, respectively), Chapter 15 (on vitamin/trace elements) and Chapter 16 (on gastrointestinal function) relevant. Nutrition is an important topic, as about 1 billion of the world’s population are overweight yet, ironically, at the same time approximately 1 billion are undernourished or starving. Adequate nutrition is essential for a variety of reasons, including optimal cardiovascular function, muscle strength, respiratory ventilation, protection from infection, wound healing and psychological wellbeing. The principles of carbohydrate and lipid metabolism and gastrointestinal digestion and absorption all have important implications in the management of nutrition, and of intravenous (parenteral) nutrition in particular. These principles, including those of fluid and electrolyte homeostasis, must be fully understood in order to manage patients receiving parenteral nutrition. Daily energy loss as heat is about 120 kJ (30 kcal) per kilogram of body weight in a normal adult. In addition, there is a daily protein turnover of about 3 g/kg body weight (about g of nitrogen), of which about g of nitrogen/kg body weight is excreted (1 g of nitrogen is derived from about g of protein). These losses are usually balanced by dietary intake of equivalent amounts of energy, as carbohydrate, fat and protein. Glucose provides 4 kcal/g, and fat 9 kcal/g. Excess energy is stored as glycogen and triglyceride. If expenditure exceeds intake, these energy stores are drawn upon. In a well-nourished adult, enough energy is stored as hepatic glycogen to last at least a day, and therefore post-operative patients without complications do not .
