THERAPEUTIC NUTRITION THERAPEUTIC NUTRITION A practical guide DR C. R. PENNINGTON King's Cross Hospital Dundee Scotland SPRINGER-SCIENCE+ BUSINESS MEDIA, B.V. © C. R. Pennington 1988 Originally published by Chapman and Hall in 1988 ISBN 978-0-412-29230-9 ISBN 978-1-4899-7108-1 (eBook) DOI 10.1007/978-1-4899-7108-1 This paperhack edition is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisher's prior consent in any form ofbinding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. All rights reserved. No part ofthis book may be reprinted or reproduced, or utilized in any form or by any electronic, mechanical or other means, now known or hereafter invented, including photocopying and recording, or in any information storage and retrieval system, without permission in writing from the publisher. British Library Cataloguing in Publication Data Pennington, C. R. Therapeutic nutrition : a practical guide. 1. Diet therapy 2. Nutrition I. Title 615.8'54 RM216 CONTENTS Preface ix 1 Introduction 1 2 Physiology and biochemistry in the 6 normal and malnourished 2.1 Body composition 6 2.2 Body compartments 10 2.3 Fuel composition 12 2.4 Metabolie biochemistry 13 2.5 Response to starvation and injury 22 2.6 Digestion and absorption 27 2.7 Intestinal adaption 33 2.8 Waterand electrolyte metabolism 34 Riferences 39 3 The diet and nutritional requirements 41 3.1 Food 41 3.2 Dietary components 45 3.3 Food additives 52 3.4 Food processing 53 3.5 Nutritional requirements 55 3.6 The healthy diet 60 3.7 Nutrition in childhood, pregnancy and old age 63 Riferences 66 vi Contents 4 Malnutrition 67 4.1 The recognition of malnutrition 68 4.2 The consequences of malnutrition 78 4.3 The causes of malnutrition 84 4.4 Other forms of malnutrition 89 References 91 5 Enteral nutrition 93 5.1 The role of enteral nutrition 94 5.2 Nutrient solutions 95 5.3 Methods of enteral feeding 106 5.4 Complications of enteral feeding 114 5.5 Patient monitoring 116 5.6 The cost of enteral feeding 117 References 117 6 Parenteral nutrition 119 6.1 lndications for parenteral nutrition 119 6.2 Parenteral nutrients 122 6.3 Nutrient administration 130 6.4 Central venous catheters 135 6.5 Complications of parenteral nutrition 144 6.6 Patient monitoring 156 6.7 Horne parenteral nutrition 158 6.8 The cost of parenteral nutrition 161 References 162 7 Nutrition in disease 165 7.1 Gastrointestinal disease 165 7.2 Diseases of the pancreas 175 7.3 Diabetes mellitus 176 7.4 Diseases of the liver 180 7.5 Alcohol-related disease 183 7.6 Cardiovascular disease 185 7.7 Hyperl i pidaemia 190 7.8 Renal disease 193 7.9 Respiratory disease 199 7.10 Haemopoietic diseases 201 7.11 Diseases ofbone 204 7.12 Neurological disease 206 Contents vii 7.13 Obesity 208 7.14 Anorexia nervosa and bulimia nervosa 213 7.15 Cancer 215 7.16 Inborn errors of metabolism 216 7.17 Intensive care 218 7.18 Nutrition in miscellaneous disorders 221 References 223 8 Diet and disease 226 8.1 Food poisoning 226 8.2 Food intolerance 236 8.3 Therapeutic dietetics 242 References 262 9 Drugs and nutrition 263 9.1 The inftuence of drugs on nutritional status 263 9.2 The inftuence of nutrition on drug metabolism 267 9.3 Drug delivery during artificial nutrition 269 References 270 Index 271 PREFACE Although the subject of nutrition is of major importance in most branches of medicine it has only recently attracted the attention of many clinicians and still receives little emphasis in the undergraduate curricula of most medical schools. There is now an increasing appreciation of the role of nutrition in the pathogenesis of many forms of chronic disease and the development of methods of nutritional support for the management of intestinal failure represents one of the most important and least heralded advances in therapeutics. This book is intended as a source of practical information on therapeutic nutrition. I hope it will be of value to the senior undergraduate who is learning about clinical practice, and the junior doctor who is training for postgraduate diplomas. I wish to express my thanks to my secretary, Miss Alison Mclntosh, for her invaluable help in deciphering and typing the manuscript, toMiss Maureen Sneddon ofthe Department ofMedical Illustration, Ninewells Hospital, for help with the illustrations and to my wife, Jane, for her support and professional dietetic advice. 1 INTRODUCTION The subject of nutrition is relevant to the entire spectrum of medical practice. Under-nutrition, over-nutrition and inappropriate nutrition are all major factors in the pathogenesis of disease. Disease frequently Ieads to malnutrition. In hospital practice nutritional therapy is primarily concerned with the treatment of malnutrition and with the prevention and management of disease. Following the discovery of vitamins, the description of vitamin deficiency syndromes and the recognition of the features of protein energy malnutrition, the subject of nutrition attracted little further medical interest and has been given little emphasis in the under graduate medical curriculum. Consequently medical graduates frequently have no concept of the importance of nutrition and poor understanding of dietetics. Nevertheless the same people are given responsibility for the supervision of ill and post-operative patients. It is not surprising that under-nutrition escapes recognition until malnutrition is severe. Many sturlies have shown that malnutrition is common in hospital practice, in both medical and surgical patients in Britain and the USA. Frequently nutritional status deteriorates during in-patient management: this applies particularly to surgical practice. Consequently many patients are at increased risk of complications such as infection and delayed wound healing which in turn impose additional nutritional demands. Common errors of nutritional management include a delay in establishing nutritional support, the failure to utilize fully the enteral route, and inexpert administration of parenteral nutrition which is expensive in terms of cost, resources and morbidity. 2 Introduction The recent resurgence of interest in the problern of malnutrition in hospital practice is attributable to a variety of factors. These include the recognition that malnutrition is common in hospital patients and the realization that weight loss is associated with morbidity and mortality in addition to that attributable to underlying disease. The emergence of gastroenterology as a speciality and the increased incidence of intestinal disease such as Crohn's disease has led to the concept ofintestinal failure. This in turn has stimulated the develop ment of methods of nutritional support. Finally the introduction of more aggressive forms of surgical and medical treatment and the development of intensive care have increased the number of patients with multi-system failure who require nutritional therapy as part of their management. Nutritional advisory groups and nutritional support teams have been formed in many hospitals by interested members of staff to develop and apply nutritional support techniques. The composition of a nutritional support team is outlined in Table 1.1. The members have individual and collective responsibilities. The anaesthetist supervises the nutritional management of patients in the intensive care unit and is frequently called upon to insert temporary central venous catheters. The bioehernist is responsible for biochemical monitaring which is particularly important in patients who require prolonged total parenteral nutrition and those with severe malnutrition or organ failure. The dietitian is involved in patientmonitaring and advising on the provision of macro- and micronutrients particularly in patients with anorexia, malabsorption and those who are being transferred from parenteral to enteral feeding. In addition, the dietitian is normally responsible for the selection of enteral feeds. The nurse supervises catheter care techniques and the administration of nasa enteral feeding. The pharmacist advises on nutrient compatibility and is responsible for the compounding of parenteral solutions. Occasional recourse to the microbiologist is also rcquired during episodes of catheter-related sepsis. The collective responsibilities of the nutrition team are outlined in Table 1.2. A dynamic team can be very effective in a variety of ways. Increasingly one of the most pressing responsibilities is cost con tainment. This is facilitated by limiting the range of enteral feeds tobe stocked by the pharmacy and encouraging the use ofthe less expensive polymeric preparations where possible. Economies arealso achieved by the careful selection of patients for parenteral nutrition and