The use of dietary supplements has increased dramatically as our knowledge about the role of nutrients and other bioactive components of food in health has increased. Although much of the information about the diet and health connection that has driven this trend is related to the reduction of chronic disease risk in adults, belief in the prophylactic use of dietary intervention, including the use of dietary supplements, has been extended to consumers throughout the life cycle.
In response to a congressional mandate, the Office of Dietary Supplements (ODS) of the National Institutes of Health (NIH) organized a conference/workshop in January 2000, to explore the current state of our knowledge about the important issues related to bioavailability of dietary supplements. The conference, supported by a consortium that included organizations both within the federal research community (NIH, U.S. Department of Agriculture, the Food and Drug Administration, and the Centers for Disease Control and Prevention) and outside it, was intended to identify research needed to expand our knowledge about factors influencing the digestion, absorption, and biological activity of nutrients and other bioactive components of dietary supplements. One clear finding that emerged from these discussions was that the use of dietary supplements in children (infancy through adolescence) is increasing. However, little is known about either the evidence base to support appropriate indications, or the safety of these supplements for use by children.
To address this knowledge gap, the Office of Prevention Research and International Programs of the National Institute of Child Health and Human Development (NICHD) and the NIH ODS organized a conference to focus on dietary supplement use in children. In determining the scope of issues to be covered at the conference, the organizers utilized the definition of dietary supplements as provided by the Dietary Supplement Health and Education Act of 1994 (DSHEA) which specifies the following:
The Dietary Supplement Health and Education Act defines dietary supplements as: a product (other than tobacco) intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, mineral, amino acid, herb or other botanical; or a dietary substance for use to supplement the diet by increasing the total dietary intake; or a concentrate, metabolite, constituent, extract, or combination of any ingredient described above; and intended for ingestion in the form of a capsule, powder, softgel, or gelcap, and not represented as a conventional food or as a sole item of a meal or the diet. (DSHEA, Public Law 103-417, October 25, 1994)
The specific goals of the conference were to:
- Identify key gaps in our knowledge about factors influencing use, justification, and safety of dietary supplements in children
- Establish a realistic research agenda that can be used for future program planning to address these gaps
The conference consisted of presentations by a distinguished faculty of scientists, administrators and others involved research and activities related to dietary supplement use in children Six general topical areas included in the conference and reported in this supplement were:
- Overview of Dietary Supplements
- Patterns of Use
- Justification for Use
- Factors Influencing the Decision to Use Dietary Supplements
- Research Issues
Working Group Deliberations
The working group discussions dovetailed with the themes presented in the plenary sessions and provided opportunities for cross-fertilization of ideas from members of each stakeholder community. There were four working groups assigned the following topics:
||What are the essential components of a process to provide science-based justification for dietary supplement use in children?|
||What are the essential components of the safety analysis relative to dietary supplement use in children? The group discussion included recommendations about what might be the best process for ensuring safety of dietary supplements for children. Options covered included the classical toxicology approach versus risk analysis, and the safe upper limits approach employed by the National Academy of Sciences in its re-evaluation of Recommended Dietary Allowances. Discussions also addressed the need to understand potential physiological differences (e.g., developmental pharmacology) that might impact on the safety evaluation of dietary supplements used by children.|
||Methodologies-experimental design issues: designing studies involving children: What are the ethical and scientific issues that should be addressed in investigations involving children? These discussions were focused around two core issues: |
- Biomarkers/outcomes for interventions and descriptive studies
||Social/cultural and behavior factors associated with patterns of use in children: |
- How can we get input from and to consumers about dietary supplement use in children?
- What factors need to be evaluated to determine how attitudes and behaviors are formed relative to the use of dietary supplements?
The following is the summary of the recommendations from each working group.
||Essential components for science-based justification |
- Application of disease prevention and health promotion principles is needed to identify areas of critical need
- Guidelines for the conduct of research should be targeted to specific age groups
- Identification of funding sources (public and private) is vital to the conduct of such studies
- Establishing safe upper limits for dietary supplements is essential, using ephedra as an example for non-nutrients
- Exposure/consumption of dietary supplements in children is needed to establish research priorities
- Researchers need to develop appropriate in vivo and in vitro models for safety testing and surrogate metabolic markers
- A consumer/health professional education component is also important
- Research needs to determine if there is an evidence-based justification for concern about high levels of intake of dietary supplements. For example, is there a basis for concern about either short-term or long-term intakes of vitamins or mineral supplements above recommended amounts?
- Identification of key indicators of dietary supplement use for use in surveillance of target populations should be an essential element of these methodologies
- Biomarkers of exposure, effect, and susceptibility to disease and potential adverse outcomes are needed for both observational studies and for assessing impact of interventions
- Identification of indicators of interactions of supplements with other supplements, drugs, and/or nutrients is important in study design
- Career development and training opportunities should also be components
||Social/cultural and behavior factors |
- Research methodologies are needed to get input from and to consumers
- Knowledge and attitudes of caregivers/parents and how they are developed need to be evaluated to determine the impact of such environmental factors on dietary supplement use by children
- Sources of information/context, including cultural context, peer-group influences, knowledge, attitudes and beliefs of health-care providers, and impact of the media should be considered
- Researchers need to consider dietary supplement use in chronic diseases. For example, studies are needed to determine how supplements are used and perceived by caregivers and users
Follow-up Activities and Concluding Remarks
After the conference, members of the conference organizing committee and representatives of various institutes and centers from within the NIH and the federal research community held a meeting to identify the following research priorities:
- Identification of ways to better utilize currently available national survey data to determine the extent of dietary supplement use, what supplements are being used and what factors are influencing the use of dietary supplements in children
- Development of surveillance methodologies with specific reference to dietary supplement use: types, amounts, use patterns, predictors of use, etc
- Increased training opportunities in the area of nutrition to support expanded efforts to provide evidence-based justification for interventions, including dietary supplements, for disease prevention and treatment
- Advancement of a research agenda to investigate:
- Prevalence and impact of the use of performance enhancing dietary supplement use in children
- An expanded understanding of health disparities in the context of disease prevalence and prevention including an emphasis on understanding the factors influencing the use of dietary supplements and/or alternative and complementary medicine
The organizers of this conference are particularly grateful for the support of all of the members of the conference consortium. Organizations providing support for this conference included: NICHD, ODS, CDC, National Center for Complementary and Alternative Medicine, NIH Division of Nutrition Research Coordination, International Life Sciences Institute, Mead Johnson Nutritionals, Whitehall Robbins HealthCare, Consumer Healthcare Products Association, and with additional support from SmithKline Beecham Consumer Healthcare LP.
Description of the conference