Nearly 2,500 years ago, Hippocrates, the "father of modern medicine," embraced the concept, "Let food be thy medicine and medicine be thy food." Medicinal herbs have been used since time immemorial in all cultures the world over. Even though we know that diet plays a significant role in 5 of the 10 leading causes of death (including coronary heart disease, stroke, certain cancers, type 2 diabetes, and atherosclerosis), the advent of modern pharmaceutical therapy in the nineteenth century caused the unfortunate fall of the "food as medicine" philosophy within the practice of modern medicine.
The passage of the Dietary Supplement Health and Education Act of 1994 (DSHEA) marked a new era for the importance of nutrition in human health. Millions of consumers have embraced the concept of using food, dietary supplements, and herbal extracts to positively affect their health, and the dietary supplement industry has grown from almost zero to more than $20 billion in annual domestic sales, with worldwide sales exceeding $100 million. Although estimates vary, approximately 60% of adults in the United States identify themselves as consumers of dietary supplements; according to the Food and Drug Administration (FDA), close to 200 million Americans consume supplements.
Despite the widespread use of dietary supplements by American consumers, studies show that physicians and other health professionals are both unlikely to ask and unlikely to be told of their patients' use of supplements. This is partly because of the often daunting challenge of determining the proper clinical usage and relevance of dietary supplements.
The broad definition of dietary supplements encompasses a wide variety of plant constituents (roots, leaves, stems, etc.), vitamins, minerals, amino acids, and other ingredients that can have essential or nonessential bioactive constituents with associated health benefits (or risks).
Consumers tend to use dietary supplements either as "preventive nutrition" (e.g., a daily vitamin E supplement taken to prevent heart disease) or as "phytomedicine" (e.g., Ginkgo biloba used to alleviate mental dysfunction associated with senile dementia). Of course, consumers also use dietary supplements in myriad other ways as promoters of weight loss, to increase energy levels, and to treat specific diseases.
Although the FDA regulates dietary supplements in many of the same ways that it regulates conventional foods, supplement products are required to carry the disclaimer, "This product is not intended to diagnose, treat, cure, or prevent any disease." Like foods, but unlike drugs, most dietary supplements do not require premarketing approval by the FDA, but the FDA has the authority to restrict sales and remove specific supplements from the market if they are shown to pose a public health risk. Because the scientific and medical evidence for the efficacy and safety of dietary supplements is highly variable in terms of both quantity and quality, it is incumbent on health professionals to actively inform patients and clients of the risks and benefits associated with the use of these products. To do that, health professionals need to have a basic understanding of the evidence (for and against) the use of a particular supplement in a given condition or for a given effect.
This book is an effort to do just that: to provide health professionals with the background needed to converse with their patients or clients about the clinical evidence behind a wide variety of dietary supplements. Consumers need to realize that dietary supplements are not panaceas or "magic bullets" that can counteract poor health habits; rather, they are supplements to a comprehensive lifestyle approach to good health that also includes a balanced diet, regular physical activity, stress management, and other positive health practices.
As consumers in modern societies have become more interested in accessing herbal medicines in trade and through the recommendation of health care professionals, the clinical evidence for herbal medicine has grown significantly. Since the passage of the DSHEA, a tremendous amount of clinical investigation has been conducted into herbal medicine and other dietary supplements. This clinical evidence lessens the validity of doctors and pharmacists not wanting to supervise the use of supplements. It is especially important to recognize the tremendous importance of traditional medicine in developing the safe use of herbs.
The goal of the purely clinical approach taken in evaluating and reviewing dietary supplements is to review dietary supplements only on scientific merit to date. As the scientific community is better able to find appropriate methods of studying the merits of traditional medicine, we expect the use of these substances will become an increasing part of health care maintenance in mainstream medicine, as well as provide further credibility to traditional healing methods.
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