Margot Gosney is Professor of Elderly Care Medicine at the University of Reading and Consultant Physician at the Royal Berkshire NHS Foundation Trust. Here she reviews the Manual of Nutritional Therapeutics.
The 6th edition of this very detailed book has just been published: the fact that it has continued to be relevant and required reading since its first publication in 1983 indicates its usefulness. The American editors have gone out of their way to cover subjects not only in great detail, but also to provide very relevant and up to date references to support the chapters.
The section on “Recommendations for healthy elderly adults” is very detailed and some of the tables, particularly the recommended dietary allowances, are a good reference source. The detail delivered by this book enables the reader to understand many recommendations about RDA. For zinc, they describe how endogenous losses decline as zinc absorption declines with age, and therefore help the clinician to understand areas that are potentially puzzling. They stress that zinc balance is preserved: whilst zinc is important for maintaining immune function, they are pragmatic in their advice about recommended zinc intakes; one hundred and twenty three references support this chapter.
There is careful consideration of nutrition in chronic diseases too: one of the most helpful tables is the nutritional alterations in starvation, cachexia and sarcopenia, which is used to illustrate how total energy expenditure decreases in all three conditions, even though the resting energy expenditure increases significantly in cachexia. Whilst protein synthesis is severely diminished in starvation and declines in sarcopenia, it may increase or decrease in the condition of cachexia. The role of insulin resistance and serum cortisol in all three conditions is compared. Chapters also compare the findings of various international task forces on the modifiable dietary risks associated with cancer. This is particularly interesting with the variability in the number of servings of fruit and vegetables per day that are recommended by different organisations. Probably of no surprise to many of us is that the recommendation is greater than five portions, although this is not consistent. Similar discrepancies are seen in the grams of salt per day dietary recommendation. These vary from < 2.3 gms to 6gms; a clear indication of differing interpretations of the same research data.
The U.S. basis of this book influences some recommendations (e.g. the use of anabolic steroids for increase fat-free mass in patient with cancer) and may therefore not appeal to all countries. This book does not lack detail but the reader may find themselves overwhelmed with data in the absence of clear recommendations for all conditions that are relevant to everyday clinical practice.
For me, the most informative parts are the tables, where clinical and biochemical advice is given in parallel, e.g. monitoring the patient using tube feeding. The book, for me, compares to a book of poetry: it is perfect to dip in and out of, individual parts may touch different people, and everyone’s interpretation of the same passages may be different. Look at it in the library and decide if you can do without the data. I will be using a fact per day from it on Ward Rounds to enhance the science behind the clinical decision making.