The DSHEA defines dietary supplements for regulatory purpose within the United States. The Office of Dietary Supplements at the NIH needed to implement research priorities using this definition and yet in some manner group the wide array of supplement ingredients available in the marketplace into more manageable categories. A definition was needed that also could be interpreted more readily in terms of research projects. An operating definition was requested in meetings with the NIH Institute Directors and other agencies who expressed difficulty in understating whether or not specific ingredients would be supported in the research and education programmes developed by the ODS. The resulting operating definition and categorization of dietary supplement ingredients was developed in collaboration with the staff of the Office of Special Nutritionals at the Food and Drug Administration (FDA), who had oversight for dietary supplement regulatory affairs, and a large group of ad hoc advisers who assisted the ODS in developing its strategic plan (see description below). Since dietary supplements found in the marketplace are not only available as single nutrients or plant-derived compounds but often in combinations, the ODS refers to dietary supplement ingredients in its writings and only uses the term 'dietary supplement' to refer to a specific product. This operating definition was developed with the understanding that the ODS would be addressing its activities to only those supplement ingredients that met the 'intended use' as dietary supplements and delivery methods described in the DSHEA. The final operating definition is given in Box 1.2.
In operationally defining dietary supplements, the ODS indicated that some ingredients may in fact be whole plants, plant parts, plant-derived, or modified foods that are termed 'functional foods' or compounds that are referred to as 'nutraceuticals' if in fact these compounds meet the requirements of the DSHEA. The ODS staff made this decision with care because the terminology in the late 1990s in the US was very confused, and the same compounds, particularly plant-derived materials, were termed differently by manufacturers, yet all were being marketed as dietary supplements in order to fit under the DSHEA regulatory umbrella. By designating the intended use of a product as a dietary supplement the manufacturer could avoid the more lengthy and costly review of the product as a drug or food. In addition, new terms were proliferating in an attempt to carve out market share among competing companies. The most common of these terms which have emerged with distinctive definitions that currently have become well understood in the marketplace are 'functional foods' and 'nutraceuti-cals' (see Box 1.3). The development of both of these product domains has led to extensive, high-quality research areas that are producing exciting new information related to the links between plant-derived materials, synthetic compounds and human
Following DSHEA, a dietary supplement is viewed by the ODS as any substance that is consumed in addition to the regular diet — that is, in addition to meals, snacks and beverages — and follows the methods of delivery clauses outlined in the Act. Food items, in any physical form (such as a liquid or a powder intended to be added to a liquid, etc.) that are intended to be a sole source of nutrition, meal replacements or conventional foods are not dietary supplements as defined in DSHEA, and thus are outside of the scope of ODS (ODS, 1998, p. 7).
Box 1.2 ODS operating definition of dietary supplement health. Other terms such as 'holistic medicines', 'herbal medicines', 'healthful herbs', continue to emerge and are confusing to the consumer in the United States. None of these terms have been accompanied by the development of clear definitions or research approaches that have been long-lived. None were incorporated into the operating definition or categories for research of the ODS.
The ODS reviewed the situation with functional foods and nutraceuticals as part of their strategic planning process. Based on the DSHEA, the operating definition of dietary supplements, and the then current definitions of functional foods, nutraceuticals and other market terminology, the ODS included in its strategic plan a statement of its assumptions and general approach to supporting research and related activities (see Box 1.4). This approach acknowledges that key dietary supplement ingredients that warrant research on efficacy and safety may be termed or contained in nutraceuti-cals or derivatives from functional foods. Such a clarification may not be warranted if the ODS strategic plan were written now, since these terms, in particular, have become more specifically defined and are much more widely understood through the growth in research and research publications (cf. Corridan et al., 2001; McCusker et al., 2001; Murray et al., 2001; Velmurugan et al., 2001; Zeisel, 2001). A recent discussion of the definition and regulations regarding nutraceuticals can be found in Zeisel (2001).
In the mid-1990s identification and verification of plant parts was problematic. Many companies were importing raw ingredients for dietary supplements as powders from outside the United States and the speciation was unclear. Rarely were pressed
Functional food — any modified food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains (Thomas and Earl, 1994).
Nutraceutical — any substance that may be considered a food or part of a food and provides medical or health benefits, including the prevention and treamtent of disease (DeFelice, 1993).
Nutraceutical — those diet supplements that deliver a concentrated form of a presumed bioac-tive agent from a food, presented in a nonfood matrix, and used to enhance health in dosages that exceed those that could be obtained from normal foods (Zeisel, 2001)
Box 1.3 Definitions of functional foods and nutraceuticals in common use in the United States
Therefore, the ODS will identify and foster research on the health benefits and risks of substances based on the merit of the underlying scientific evidence regardless of how they might be currently incorporated into the different categories of commercial products or their regulatory status in the commercial marketplace. This approach allows the ODS flexibility to address the scientific questions relevant to the role of specific substances in promoting health without being unnecessarily constrained by the nuances that bear on whether a substance may be lawfully used in a dietary supplement, or whether specific information on the label/ labeling causes a product to be marketed under regulatory frameworks other than as a dietary supplement. (ODS, 1998 p. 8)
Box 1.4 ODS approach to the variability of terminology of dietary supplements and dietary supplement ingredients voucher plant specimens sent with the powders to verify the taxonomy. Often, plant material was identified only by a common name from the country of origin, not by the standard Latin binomial. Common names for the same plant species vary from country to country and often across regions within the same country.
In 1992 the American Herbal Products Association (AHPA) published a compendium that linked all common plant names they could identify with appropriate internationally recognized scientific names (AHPA, 1992). The goal of AHPA was to reduce the confusion in the marketplace of the diversity of common names and outdated scientific nomenclature by advocating for the establishment of a 'uniform common name with a uniform Latin name' (p. I). The publication, Herbs of Commerce, included 550 primary species with 1800 cross-referenced synonyms. The book was prepared primarily to support the plant-derived dietary supplement, spice and herb industry and, as a result, it provided a rough definition of the diversity of the plant-derived products available in the US market in the early 1990s.
In order to deal with this diversity of dietary supplements of plant origins coupled with other substances that were defined by the DSHEA, the ODS used the expertise of the individuals who participated in their strategic planning process to group supplements into categories that could be discussed and addressed by research in a more meaningful manner. Since dietary supplements typically contain one or more ingredients, the ODS grouped these ingredients into three categories: botanicals, nutrients and other dietary substances as defined in Box 1.5. These categories therefore provided further elaboration on the operating definition and stated approaches. Clearly, the dietary supplement ingredients of plant origin far overshadowed the number of ingredients in the other two categories. Botanical supplement ingredients also included the
Botanical ingredients include all plant-derived materials whether fresh, preserved, or dried full plants, plant parts, plant species mixtures, plant extracts, and compounds found in such materials. Thus, items that are commonly termed 'herbs' or 'herbal products', regardless of whether they meet the dictionary definition of herb1 or that are comprised of parts, extracts, or preparations of woody plants will be included as botanical ingredients.
Nutrient ingredients include all essential and non-essential nutrients and other food constituents, that are typically described in standard nutrition reference texts or that fall within the review parameters of the Food and Nutrition Board, National Academy of Sciences in consideration of Dietary Reference Intakes (DRIs). Thus, this category would include substances recognized as essential nutrients (i.e., iron, vitamin C, essential amino acids, etc.) and substances not generally recognized as being essential but that have or may have a dietary or nutrient role in humans.
Other dietary substances comprises a broad and diverse group of substances that are neither of plant origin nor alone could be viewed as 'nutrients' within the common-sense meaning of the term. For example, such substances could include animal or plant metabolites or constituents, microorganisms and certain of their constituents, etc. The substances subject to inclusion in this category are limited by the statutory definition of 'dietary supplement' in the DSHEA (i.e., not an approved or investigational drug, not a conventional food or meal replacement, and intended to be used to supplement the diet, etc.).
1 Herb — a flowering plant whose stem above ground does not become woody.
Box 1.5 Categories of dietary supplement ingredients most diverse preparations, sources of origin and questions regarding the consistency of all aspects of production and marketing. As a further indication of the growth in the diversity of the dietary supplement ingredients of plant origin, AHPA recently published the second edition of Herbs of Commerce, which includes over 2,000 plant species (AHPA, 2000).
Because the focus of this present book is dietary supplements of plant origin, the authors use the term 'dietary supplement' to roughly equate to botanical supplements or supplement ingredients. While some authors discuss dietary supplement products that contain multiple ingredients, most are focused on the science behind the bioac-tive compounds in one plant species or specific plant parts of one or related plant species.
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