The present volume is one of a series concerned with topics considered to be of growing interest to those whose ultimate aim is the understanding of the nutrition of man. Volumes on Sweetness, Calcium in Human Biology and Sucrose: Nutritional and Safety Aspects, have already been published, and another, on Dietary Starches and Sugars in Man: A Comparison, is in preparation. Written for workers in the nutritional and allied sciences rather than for the specialist, they aim to fill the gap between the textbook on the one hand and the many publications addressed to the expert on the other. The target readership spans medicine, nutrition and the biological sciences generally and includes those in the food, chemical and allied industries who need to take account of advances in these fields relevant to their products. Funded by industry but with an independent status, the Inter national Life Sciences Institute (ILSI) is a non-profit organization founded to deal objectively with the numerous health and safety issues that today concern industry internationally. ILSI sponsors scientific research, organizes conferences and publishes monographs relative to these problems. London Ian Macdonald March 1988 Series Editor Preface This volume has been prepared at a time when interest in both the biological roles of zinc and its nutritional significance is growing rapidly.