Aryana Libris

Authors : Coates Paul M. - Coates Paul M. - Betz Joseph M. - Blackman Marc R. - Cragg Gordon M. - Levine Mark - Moss Joel - White Jeffrey D.
Title : Encyclopedia of dietary supplements
Year : 2010

Link download : Coates_Paul_M_-_Encyclopedia_of_dietary_supplements.zip

Preface. Welcome to the second edition of Encyclopedia of Dietary Supplements, reflecting the combined efforts of more than 100 authors from 13 countries on 97 topics. Response to the first edition, published in 2005 and then supplemented by a series of online chapters, prompted us to revise and expand the Encyclopedia. There has been considerable expansion in research on many dietary supplements and their ingredients. We expect that this Encyclopedia will continue to be a valuable reference for students and researchers in physiology and chemistry, for health care providers, and for consumers who are interested in understanding the kind of science that is—or is not—behind the claims that are made for dietary supplements that are sold throughout the world, where standards of government regulation differ from country to country. In the United States, sales of products in the dietary supplement market approached $25 billion in 2009. Their form and their labeling are regulated by the Food and Drug Administration (FDA) as a result of legislation passed in 1994 called the Dietary Supplement Health and Education Act (DSHEA). The dietary supplement category in the United States includes vitamins, minerals, and other ingredients that are found in foods, as well as ingredients not ordinarily found in foods—such as extracts of herbs and other natural products—that are used by consumers for their potential health-promoting, disease-preventing, or performance-enhancing properties. Many of these are represented in the chapters of this book. The Encyclopedia is not just for consumers in the U.S. market, although we acknowledge that the term “dietary supplements” is an American expression. We are not aware of any other single term that describes all of the substances that we wish to include in this Encyclopedia, although terms such as food supplements, nutritional supplements, or natural health products have been applied as well. Sometimes the claims for benefit of specific products are borne out by well-documented scientific studies. In other cases, they are not, or the science to support their use is still at an early stage. Enthusiasm for their use may be based on popular legend or on longstanding patterns of use in traditional healing systems. In this book, we hope that readers will be able to examine the types of evidence that have been used to support claims of benefit and safety. The goal of this book is to provide readers with comprehensive, yet accessible, information on the current state of science for individual supplement ingredients or extracts. To this end, each entry reviews basic information available about the ingredient including, where applicable, its chemistry and functions, before detailing the preclinical and clinical literature. Articles conclude with references to the relevant literature. Given the large number of dietary supplement products in commerce, this book covers only a small fraction of them, with selection based primarily on the frequency of their use and the availability of a sufficient science base to discuss their efficacy and safety. It is clear that the level of scientific information available differs markedly among the various entries. For many ingredients, the chemistry and physiology, preclinical and clinical information, and mechanism of action are well known. For others, by contrast, some or many pieces of these data are missing. The preparation of some commercial products is of high quality and follows good agricultural, laboratory, and manufacturing practices. Again, by contrast, the preparations for others have not been reliable, making them subject to high variability in content and possible contamination. As dietary supplement use becomes more widespread, there are growing concerns about safety of some ingredients, including possible harmful interactions between supplements and prescribed drugs. When known, this information is included in the chapters of this book. These issues should form the basis for future research. The field of dietary supplements is a rich one, and the science related to this large class of ingredients is expanding all the time. All the chapters that appeared in the first edition have been revised and updated for this edition. In addition to providing these updated chapters, we have included 12 additional chapters on topics not previously covered, reflecting the emergence of dietary supplements in the marketplace, as well as the science behind them. There is also a new chapter on the challenges of dietary supplement research. Additional changes involve gathering several related chapters under “umbrella” topics: Carotenoids and Polyphenols. Two of the chapters in this edition of the Encyclopedia, on Ephedra and Androstenedione, were commissioned before their status as dietary supplements in the U.S. market was changed. In 2004, the FDA banned ephedra-containing products from the dietary supplement market in the United States. Also in 2004, the FDA issued warning letters to companies then marketing products containing androstenedione; the regulatory status of these products as dietary supplements has therefore changed. Nevertheless, until recently, both ephedra and androstenedione were widely consumed in the United States.We felt, therefore, that discussion of the science of these ingredients was important. The chapters have been updated to reflect the new regulatory status of these ingredients. Where possible and applicable, chapter names for botanical ingredients have been adapted to conform to the standardized common names in the American Herbal Products Association’s Herbs of Commerce, Second Edition (2000). The accepted scientific names (with authority) and additional synonyms may be found in the individual chapters. We express our thanks to the authors of the individual chapters. This is a challenging and somewhat controversial field, but we believe that our authors have provided a balanced and current view of the literature. We also acknowledge with gratitude the hard work and guidance of Informa Healthcare’s editorial staff, particularly the project editor, Timothy DeWerff. Finally, we wish to emphasize that the inclusion of chapters on particular dietary supplements in this Encyclopedia does not imply that we endorse them. Paul M. Coates Joseph M. Betz Marc R. Blackman Gordon M. Cragg Mark Levine Joel Moss Jeffrey D. White. ...