Why an encyclopedia? The original Greek word means ‘the circle of arts and sciences essential for a liberal education’, and such a book was intended to embrace all knowledge. That was the aim of the famous Encyclopedie produced by Diderot and d’Alembert in the middle of the 18th century, which contributed so much to what has been called the Enlightenment. It is recorded that after all the authors had corrected the proofs of their contributions, the printer secretly cut out whatever he thought might give offence to the king, mutilated most of the best articles and burnt the manuscripts! Later, and less controversially, the word ‘encyclopedia’ came to be used for an exhaustive repertory of information on some particular department of knowledge. It is in this class that the present work falls.
In recent years the scope of Human Nutrition as a scientific discipline has expanded enormously. I used to think of it as an applied subject, relying on the basic sciences of physiology and biochemistry in much the same way that engineering relies on physics. That traditional relationship remains and is fundamental, but the field is now much wider. At one end of the spectrum epidemiological studies and the techniques on which they depend have played a major part in establishing the relationships between diet, nutritional status and health, and there is greater recognition of the importance of social factors. At the other end of the spectrum we are becoming increasingly aware of the genetic determinants of ways in which the body handles food and is able to resist adverse influences of the environment. Nutritionists are thus beginning to explore the mechanisms by which nutrients influence the expression of genes in the knowledge that nutrients are among the most powerful of all influences on gene expression. This has brought nutrition to the centre of the new ‘post-genome’ challenge of understanding the effects on human health of gene-environment interactions.
In parallel with this widening of the subject there has been an increase in opportunities for training and research in nutrition, with new departments and new courses being developed in universities, medical schools and schools of public health, along with a greater involvement of schoolchildren and their teachers. Public interest in nutrition is intense and needs to be guided by sound science. Governments are realizing more and more the role that nutrition plays in the prevention of disease and the maintenance of good health, and the need to develop a nutrition policy that is integrated with policies for food production.
The first edition of the Encyclopaedia of Human Nutrition established it as one of the major reference works in our discipline. The second edition has been completely revised to take account of new knowledge in our rapidly advancing field. This new edition is as comprehensive as the present state of knowledge allows, but is not overly technical and is well supplied with suggestions for further reading. All the articles have been carefully reviewed and although some of the subjects are controversial and sensitive, the publishers have not exerted the kind of political censorship that so infuriated Diderot.
Emeritus Professor of Human Nutrition
London School of Hygiene and Tropical Medicine