Book reviews and notices

Human body composition: Growth, aging, nutrition, and activity. Gilbert B. Forbes. Springer-Verlag, New York, 1987. 350 pages. US$66.

This book reviews modern knowledge concerning body composition at all ages and for all physiological states. The ways in which composition is influenced by nutrition, physical activity, hormones, trauma, and disease are described. The book provides comprehensive, authoritative, and readable coverage of the subject without redundancy and includes more than 40 pages of references and a good index. It will be valuable for those whose teaching responsibilities include this subject and for physicians and graduate students whose research involves body-composition measurement.

Recent advances in obesity research. Vol. 5. Edited by E. M. Berry, S. H. Blondheim, H. E. Eliahou, and E. Shafrir. John Libbey, London, 1987. 397 pages. £32; US$56.

The First International Congress on Obesity provided the basis for the first volume in this series in 1974; subsequent congresses were covered in additional volumes in 1977, 1980, and 1983. The present volume is based on the congress held in September 1986. Given the enormous interest in the growing problem of obesity in most industrialized countries and for the more affluent in developing countries, research progress justifies congresses with this frequency. The present volume consists of 56 short chapters grouped into sections on epidemiology, genetics, the relationship between diabetes and hypertension, regional differences in adipose tissue distribution and metabolism, bioenergetics and thermogenesis, the cellular characteristics of adipocytes, central and endocrine regulation of adiposity, energy balance in pregnancy and lactation, pharmacological intervention, and the treatment of obesity, including very-low-calorie diets and exercise. With such a diversity of chapters, the subject and author index is particularly useful.

Among the highlights of greatest interest are the following

• Chapter 3: As judged from measurement of total body water by dilution of stable isotopes or lean body mass determined from total body potassium, anthropometric measurements such as body mass index and triceps or subscapular skinfold indices are equally valid predictors of adiposity.
• Chapter 7: It has been repeatedly shown that decreasing body weight results invariably in a lowering of blood pressure and that increases in blood pressure correlate well with body weight increment.
• Chapter 11: The waist/hip ratio is correlated with cardiovascular risk factors and predicts stroke and myocardial infarction in both men and women.
• Chapter 43: While several chapters deal with thermogenic and lipolytic drugs for the treatment of obesity, there are as yet no safe and efficacious drugs to promote weight loss or prevent weight regain after desirable body weight has been achieved.
• Chapters 47, 49-51: While chapters 49-51 report good results with protein-sparing very-low-calorie diets in morbid obesity, Garrow (chapter 47) argues that they are unnecessary and that their misuse is potentially dangerous.

While the chapters are of variable quality and by no means constitute a complete review of the field, the book provides a good insight into the state of current knowledge and research.

Nutritional intervention in the aging process. Edited by H. James Arnbrect, John M. Prendergast, and Rodney M. Coe. Springer-Verlag, New York, 1984. 343 pages. US$51.90.

With the proportion of elderly increasing in some developing countries and already constituting 11% to 16% of the population of industrialized countries. a book on nutrition and the aging process is timely. There are two major problems: the topic is relatively new, and much of the information is extrapolated from knowledge obtained with younger age groups or extrapolated with uncertain validity from studies in experimental animals. Nevertheless, the evidence presented in many of the chapters of this book indicates that "it is presently within the power of every healthy aging individual to delay the physiological decline and body composition change by integrating exercise into the daily routine, adjusting energy intake to maintain a youthful proportion of body fat,'' and consuming a diet that meets sound guidelines. The chapters relating to the sociologic factors, age-related changes in taste and smell, and in protein, mineral and vitamin metabolism adequately cover present knowledge. Many of the other chapters are more speculative and contribute little to the book's stated purpose of identifying nutritional interventions. The book only partially succeeds in justifying its title. but until more specific attention is paid to nutritional studies in the elderly, there will be little to add.

Nutrition and aerobic exercise. Edited by Donald K. Layman. ACS symposium series, 294E. American Chemical Society, Washington, D.C., 1986. 150 pages. USA/Canada, US$34.95; export price. US$41.95.

The potential health benefits of a combined programme of nutrition and exercise are being increasingly recognized and incorporated into national dietary goals and guidelines. Based on an American Chemical Society symposium, this book provides insight into current knowledge of nutrition and exercise for both the specialist and the non-specialist. Chapters deal with biochemical adaptations induced by exercise training, the influence of exercise on fuel utilization by skeletal muscle, effects on protein and amino-acid metabolism, lipid and protein metabolism, riboflavin requirements, trace element and calcium status, and water and electrolytes. The final chapter on aerobic exercise and body composition documents the potential of exercise at any age to conserve and increase lean body mass and increase the leanness-to-fatness ratio. Aerobic exercise is particularly important in preventing obesity and retarding osteoporosis.

The opening chapter lists a series of frequently asked questions to which the book provides answers. For example:

• Is exercise important for weight control? Yes, in conjunction with diet.
• Is increased protein essential for muscle building? Any increased need is minimal, not exceeding 7 g per day.
• Does exercise reduce the risk of heart disease'' Exercise has a beneficial effect on cardiopulmonary function as well as on plasma cholesterol and lipids.
• Should athletes take vitamin supplements? With the exception of possible psychological benefits, any other suggested benefits are without sound scientific documentation.
• Are salt tablets or electrolyte drinks essential for exercise during hot weather? It is essential to maintain water intake to prevent dehydration, but electrolyte supplementation in drinking fluids is not recommended during exercise lasting less than three to five hours. Electrolyte and carbohydrate supplementation is recommended during longer work or exercise periods when regular meals are not available, especially in hot environments.
• Does aerobic exercise create an increased need for iron? There is a direct correlation of iron deficiency with impaired physical work performance, but there is no evidence that exercise increases requirements for iron or other minerals.

The book is well illustrated, and references and a useful index are provided.

Nutrition and blood pressure. Edited by Peter Bursztyn. John Libbey, London, 1987. 169 pages. £19.

A well-written and well-documented series of chapters examines the relationship between blood pressure and vegetarian diets, obesity, dietary fat, dietary fibre, alcohol, dietary sodium and potassium, and calcium. Various workers have demonstrated that hypertensive patients often respond well to, and are sensitive to, weight reduction, salt-reduced diets, abstinence from alcohol, and a reduction of saturated fat as well as combined dietary measures. Dietary changes that include increased fibre intake and reduced fat, alcohol, and salt intake coupled with weight reduction produce a clinically useful reduction in the blood pressure of moderate hypertensives. The results of the dietary approach to hypertension are comparable to those achieved by drug treatments. Peasant populations tend to have low blood pressures and little hypertension, and diet appears to be the major responsible factor. However, it is noted that the physiological links between dietary factors and blood pressure have not been demonstrated experimentally. The book is an excellent summary and source of literature on this important topic.

Vitamin A deficiency and its control. Edited by J.C. Bauernfeind. Academic Press, Orlando, Fla., USA. 1986. US$95.

There has been a new wave of concern for the continuing widespread adverse health impact of avitaminosis A. If the estimate in the foreword of "8-10 million clinical cases per year, 500,00 of whom become blind" is anywhere near correct, this renewed interest in the problem is more than justified. There are also new studies suggesting that vitamin-A deficiency increases morbidity and mortality from infectious disease.

This multi-authored hook provides a comprehensive and authoritative up-date of the major issues, beginning with global occurrence and the physiological and metabolic basis of major signs of vitamin-A deficiency. Seven chapters then deal with the control of vitamin-A deficiency by periodic oral dosing in various countries. In addition chapters deal with the vitamin-A and provitamin-A composition of foods, and with organizations involved in the effort to eradicate avitaminosis A. It is unfortunate that its price will put this valuable book out of reach for most persons in developing countries who could make the best use of it.

Gene banks and the world's food. D. L. Plucknett, N. J. H. Smith, J. T. Williams, and N. M. Anishetty. Princeton University Press, Princeton, N.J., USA, 1987. US$42.

This book provides a history of germ-plasm preservation and exchange, from botanical gardens to modern cold-storage units, and a highly readable assessment of the scientific and political ramifications of gene-bank programmes.

ACCIS guide to United Nations information sources on food and agriculture. ACCIS guides to United Nations information sources, no. 1. FAO, Rome, 1987. 124 pages.

This publication is the first in a series of subject oriented guides to United Nations information sources. It is divided into 10 chapters, dealing with food and agriculture in general; plant production and protection; animal nutrition and health; food and nutrition; land and water development and natural resources; economic and social development; trade and commodities; agro-industries and industrial development; fisheries and agriculture; and statistics. Each chapter consists of a series of brief descriptions of information sources within its subject area. Some types of sources included are libraries and other units maintaining document collections, computerized data bases, including those currently not publicly available, and publications, particularly regular serial publications such as journals, newsletters, and yearbooks and some directories. Annexes contain national contact addresses, addresses of organizations included in the guide, and addresses of commercial on-line hosts offering access to United Nations system data bases. Indexes to subjects, names of organizations and departments, publication titles, and data bases and systems are also included.