www.bmjbooks.com ABC OF NUTRITION Fourth edition Truswell Written by A Stewart Truswell General practice, Dietetics & Nutrition ABC OF NUTRITION FOURTH EDITION 44100 ABC of Nutrition 27/6/03 2:16 pm Page 1 ABC OF NUTRITION Fourth Edition ABCN-FM.qxd 7/19/03 3:32 PM Page i ABCN-FM.qxd 7/19/03 3:32 PM Page ii ABC OF NUTRITION Fourth Edition A STEWART TRUSWELL Emeritus Professor of Human Nutrition, University of Sydney, Australia with contributions from PATRICK G WALL CIARA E O’REILLY the late CHRISTOPHER R PENNINGTON NIGEL REYNOLDS ABCN-FM.qxd 7/19/03 3:32 PM Page iii © BMJ Publishing Group 1986, 1992, 1999, 2003 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording and/or otherwise, without the prior written permission of the publishers. First published in 1986 by BMJ Books, BMA House, Tavistock Square, London WC1H 9JR www.bmjbooks.com First edition 1986 Second edition 1992 Third edition 1999 Fourth edition 2003 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 0 7279 1664 5 Typeset by Newgen Imaging Systems (P) Ltd., Chennai, India Printed and bound in Spain by Graphycems, Navarra Cover shows halved apple, with permission from Gusto productions/Science Photo Library ABCN-FM.qxd 7/19/03 3:32 PM Page iv Contents Contributors vi Preface vii 1 Reducing the risk of coronary heart disease 1 2 Diet and blood pressure 10 3 Nutritional advice for some other chronic diseases 15 4 Nutrition for pregnancy 20 5 Infant feeding 24 6 Children and adolescents 32 7 Adults young and old 37 8 Malnutrition in developing countries 43 9 Other nutritional deficiencies in affluent communities 52 10 Vitamins and some minerals 59 11 Overweight and obesity 69 12 Measuring nutrition 78 13 Therapeutic diets 87 14 Food poisoning 94 Patrick G Wall, Ciara E O’Reilly 15 Food sensitivity 108 16 Processing food 113 17 Nutritional support 120 Nigel Reynolds, Christopher R Pennington 18 Some principles 125 Index 133 v ABCN-FM.qxd 7/19/03 3:32 PM Page v Ciara E O’Reilly PhD Technical Executive, Food Safety Authority of Ireland, Dublin, Ireland Christopher R Pennington MD, FRCPEd Late Professor of Gastroenterology, Ninewells Hospital and Medical School, Dundee, Scotland Nigel Reynolds MB, ChB, MRCP Medicine and Cardiovascular Group, Department of Digestive Diseases and Clinical Nutrition, Ninewells Hospital and Medical School, Dundee, Scotland A Stewart Truswell AO, MD, DSc, FRCP, FRACP Emeritus Professor of Human Nutrition, University of Sydney, Australia Patrick G Wall MB, BCh, BAO, MRCVS, MFPMM Chief Executive, Food Safety Authority of Ireland, Dublin, Ireland vi Contributors ABCN-FM.qxd 7/19/03 3:32 PM Page vi vii Preface to 3rd edition Nutrition is one of those subjects which comes up every day in general practice—or should do—yet in most undergraduate medical schools it is crowded out by the big clinical specialities and high technology procedures. It is for subjects like nutrition that the British Medical Journal’s ABC series is extremely useful. This book was started when Dr Stephen Lock, previous editor of the BMJ asked me to write a series of weekly articles for an imagined general practitioner, in an unfashionable provincial town who had been taught almost no nutrition at medical school. They now felt the need to use nutrition in the practice, but could spare only 15 to 20 minutes a week to read about it. The brief was that the writing must be practical and relevant; about half the page was to be for tables, figures, photographs or boxes (that is, not text) and these have to tell part of the story. The writing was to “come down off the fence”, to make up its mind on the balance of evidence and state it plainly. The first edition had no references but some reviewers asked for them and now in the era of evidence-based medicine some well chosen references seem indispensable when writing about nutrition. Nutritional concepts, of course, are not as tightly evidence-based as information about drugs because randomised controlled trials, so routine for drug therapy, are rare for nutrition. This book does not deal with all aspects of human nutrition, only those that are useful in everyday medical practice. The latest fads and controversies are not here either. This is the ABC of Nutrition, not the XYZ. A Stewart Truswell 1999 Preface to 4th edition When the first edition of this ABC was written in 1985 there was no “evidence-based medicine”, no human genome, no BSE or nvCJD, no epidemic of obesity and associated type II diabetes; there were no statins to lower plasma cholesterol and no genetically modified foods. Helicobacter pylori had just been discovered. The role of folate in neural tube defects had not been established, or raised plasma homocysteine as a risk factor for heart disease. The Barker hypothesis had not been propounded. These recent discoveries and ideas affect nutritional practice and they appear or influence what is in this new edition. A Stewart Truswell 2003 Preface ABCN-FM.qxd 7/19/03 3:32 PM Page vii ABCN-FM.qxd 7/19/03 3:32 PM Page viii For some doctors in affluent countries the first question about prevention of coronary heart disease (CHD) nowadays is whether to write a prescription for one of the statins (simvastatin, pravastatin, fluvastatin, atorvastatin, etc) which inhibit an early step of cholesterol biosynthesis in the body (see p 7). Tables are available to show whether the 5- or 10-year risk justifies the cost of long term statin medication, but the relation of diet and CHD is still of primary importance for the majority of people. What we eat is bound up with the aetiology of CHD. Many people do not know their current plasma cholesterol, many coronary deaths occur before medical help and most countries cannot afford these expensive drugs. Coronary heart disease is the largest single cause of death in Britain and the disease that causes most premature deaths, but it is only one-seventh as common in industrial Japan and rare in the masses in most developing countries. Its incidence must be environmentally determined because immigrant groups soon take on the incidence rate of their new country and there have been large changes in mortality over time. Coronary heart disease was uncommon everywhere before 1925 and then increased steadily in Western countries until the 1970s, except for a dip during the Second World War. Age-standardised mortality rates from coronary heart disease in the United States of America and Australia started to decline from 1966 and have reduced by more than 70%. In Britain rates are higher in Scotland and Ireland than in England, and higher in the north of England than the south. They have been declining since 1979 and have fallen by about 25%. Most EU countries have shown similar recent modest reductions of coronary mortality, but in the countries of eastern Europe coronary mortalities have risen. They have, however, recently fallen in Poland and the Czech Republic. Coronary heart disease is a multifactorial disease, but diet is probably the fundamental environmental factor. The pathological basis is atherosclerosis, which takes years to develop. Thrombosis superimposed on an atherosclerotic plaque, which takes hours, usually precipitates a clinical event. Then whether the patient dies suddenly, has a classic myocardial infarct, develops angina, or has asymptomatic electrocardiographic changes depends on the state of the myocardium. Each of these three processes is affected by somewhat different components in the diet. The characteristic material that accumulates in atherosclerosis is cholesterol ester. This and other lipids in the plaque, such as yellow carotenoid pigments, come from the blood where they are carried on low density lipoprotein (LDL). In animals, including primates, atheroma can be produced by raising plasma cholesterol concentrations with high animal fat diets. Much of this cholesterol is present in modified macrophages that have the histological appearance of foam cells. Experimental pathology studies indicate that these cells only take up large amounts of LDL if it has been oxidised. 2 This oxidation probably occurs within the artery wall. People with genetically raised LDL-cholesterol (familial hypercholesterolaemia) tend to have premature coronary heart disease. This is accelerated even more in homozygotes who have plasma cholesterols four times normal and all develop clinical coronary heart disease before they are 20. Thousands of papers have been written on diet and CHD. Since early in the century scientists have suggested links 1 1 Reducing the risk of coronary heart disease 80-84 Year Deaths per 100 000 75-79 70-74 65-69 60-64 55-59 50-54 92 91 93 90 89 88 87 86 0 90 180 270 360 450 Finland USA Australia UK Hungary Japan Coronary heart disease death rates in six countries, for men aged 25-74, 1950-83. (Adapted from Heart and Stroke Facts published by the National Heart Foundation of Australia, from WHO data.) CHD mortality in USA and Australia started to fall 10 years before any decline in UK coronary deaths and fell more profoundly. Smoking rates and medical treatments cannot explain these phenomena. They may have been due to dietary changes (increased polyunsaturated and decreased saturated fatty acids) 1 Photomicrograph of coronary artery with atherosclerosis Evidence linking diet and CHD This comes from: • animal experiments • pathology studies • genetic polymorphisms • epidemiology: ecological and cohort/prospective studies • randomised controlled trials with dietary changes. The strongest body of evidence comes from cohort studies which demonstrate environmental factors that are either associated with increased subsequent risk of CHD events (risk factors) or decreased subsequent risk (protective factors). ABCN-01 7/19/03 3:33 PM Page 1 [...]... first pass metabolism N Engl J Med 1990; 322: 95-9 Department of Health Nutritional aspects of the development of cancer Report of the Working Group on Diet and Cancer of the Committee on Medical Aspects of Food and Nutrition Policy The Stationery Office, 1998 Doll R, Peto R The causes of cancer: qualitative estimates of avoidable risks of cancer in the United States today J Natl Cancer Inst 1981;... Kalbfleisch JM Influence of nutritional factors on prevalence of diabetes Diabetes 1971; 20: 99-108 8 Report of a WHO Study Group Prevention of diabetes mellitus WHO Tech Rep Ser 844 Geneva: WHO, 1994 9 Ohlson LO, Larsson B, Svarsudd K et al The influence of body fat distribution on the incidence of diabetes mellitus 13.5 years of follow up of the participants in the study of men born in 1913 Diabetes... Randomised controlled trials are under way % of animals ABC of Nutrition 100 80 60 40 Dangerous arrhythmias Dangerous arrhythmia is one of the two major causes of death in CHD Over half the deaths occur before the arrival of paramedical or medical help Then in the ambulance or coronary care unit the treatment of ventricular fibrillation saves lives Developments in nutrition research are showing, with animal... an allergic (IgE) reaction occasionally occurs in the baby (5) The amount of caffeine in the milk after a cup of coffee is only about 2% of the maternal dose Likewise, the alcohol concentration of breast milk is about the same as that of plasma so single drinks of coffee or alcohol, well spaced out, are harmless, but the babies of alcoholics can be affected Beer stimulates prolactin secretion (at least... restriction? BMJ 1985; 290: 110-13 20 Ministry of Agriculture, Fisheries and Food The Dietary and Nutritional Survey of British Adults—Further Analysis London: HMSO, 1994 21 Bucher HC, Cook RJ, Guyatt GH et al Effects of dietary calcium supplementation on blood pressure A meta-analysis of randomised controlled trials JAMA 1996; 275: 1016-22 13 ABC of Nutrition 22 Sever P, Beevers G, Bulpitt C et al... 0.93 1.02 1.08 1.22 1.38 * 12-year follow up of cohort of 276 802 US men by stated alcohol habits at entry Reduced risk of CHD brought down total mortality at 1 and 2 drinks/day but not above Reproduced from Boffeta and Garfinkel11 Reducing the risk of coronary heart disease The management of hypertriglyceridaemia consists of looking for and dealing with any of the common associations The non-pharmacological... Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults Executive summary of the third report of the National Cholesterol Education Program (NCEP) Expert Panel of Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) JAMA 2001; 285: 2486-97 Department of Health Nutritional Aspects of Cardiovascular Disease Report on the Cardiovascular... Department of Health Nutritional aspects of cardiovascular disease Report of the Cardiovascular Review Group Committee on Medical Aspects of Food Policy London: HMSO, 1994 12 Law MR, Frost CD, Wald NJ By how much does dietary salt reduction lower blood pressure? III Analysis of data from trials of salt reduction BMJ l991; 302: 819-24 13 Beard TC, Cooke HM, Gray WR, Barge R Randomised controlled trial of a... analyses of 24-hour sodium excretion and blood pressure within and across populations BMJ 1996; 312: 1249-53 9 Department of Health Dietary reference values for food energy and nutrients for the United Kingdom Report of the Panel of the Committee on Medical Aspects of Food Policy London: HMSO, 1991, pp 152-5 10 Denton D, Weisinger R, Mundy NI et al The effect of increased salt intake on blood pressure of. .. Lancet 1991; 338: 131-7 3 Department of Health Folic Acid and the prevention of disease Report of the Committee on Medical Aspects of Food and Nutrition Policy London: Stationery Office, 2000 4 Forrest F, Florey du VC The relation between maternal alcohol consumption and child development: the epidemiological evidence J Publ Health Med 1991; 13: 247-55 [Review by members of the Dundee prospective team.] . 44100 ABC of Nutrition 27/6/03 2:16 pm Page 1 ABC OF NUTRITION Fourth Edition ABCN-FM.qxd 7/19/03 3:32 PM Page i ABCN-FM.qxd 7/19/03 3:32 PM Page ii ABC OF. www.bmjbooks.com ABC OF NUTRITION Fourth edition Truswell Written by A Stewart Truswell General practice, Dietetics & Nutrition ABC OF NUTRITION FOURTH EDITION