|NIH State-of-the-Science Panel Urges More Informed Approach
to Multivitamin/Mineral Use for Chronic Disease Prevention
Panel calls for expanded oversight of vitamin and mineral supplements
An independent panel convened this week by the NIH Office of Medical Applications
of Research and the Office of Dietary Supplements assessed the available evidence
on the safety and effectiveness of multivitamin/minerals (MVMs). Following two
days of expert presentations, public discussion, and panel deliberations, the
panel made recommendations regarding certain specific supplements but ultimately
concluded that more rigorous scientific research is needed before strong recommendations
can be made regarding MVM use to prevent chronic diseases.
The panel released a draft statement of its findings this morning, at the close
of the conference. The panel’s findings pertain to the generally healthy population,
and do not include pregnant women, children, or those with disease. Full text
of the panel’s draft state-of-the-science statement will be available late today
at http://consensus.nih.gov. The final
version will be available at the same Web site in four to six weeks.
“More than half of American adults are taking dietary supplements, the majority
of which are MVMs, and the bottom line is that we don’t know for sure that they’re
benefiting from them. In fact, we’re concerned that some people may be getting
too much of certain nutrients,” said J. Michael McGinnis, M.D., M.P.P., Senior
Scholar with the Institute of Medicine of the National Academy of Sciences, who
chaired the panel.
The panel recommended the combined use of calcium and vitamin D supplementation
for postmenopausal women to protect bone health. The panel also advocated that
anti-oxidants and zinc be considered for use by non-smoking adults with intermediate-stage,
age-related macular degeneration, an eye condition that can cause blindness.
The panel supports previous recommendations by the CDC that women of childbearing
age take daily folate to prevent neural tube defects (birth defects of the brain
and spinal cord) in infants. Conversely, it found no evidence to recommend beta
carotene supplements, a form of vitamin A, for the general population, and strong
evidence to caution smokers against taking them. Specifically, beta-carotene
was linked to an increase in lung cancer among smokers who took the vitamin regularly.
In looking specifically at MVMs for chronic disease prevention, however, the
panel found that the available data are insufficient to make a firm recommendation
for or against their use in the general population.
Of note, rates of MVM use are highest among those who engage in other positive
health behaviors such as regular exercise and eating a healthier diet, making
it difficult to determine whether the MVM alone is truly responsible for any
observed improvement in health.
Most of the public assumes that the components of MVM supplements are safe,
because many of the ingredients are found in everyday foods and the products
are available over-the-counter. The panel identified several possible risks associated
with MVM consumption, however. Among these is the potential for overconsumption
of certain nutrients, with the resulting possibility of adverse effects. Though
health-conscious individuals are likely to be focused on ensuring that they meet
the recommendations for essential nutrients, the combined effects of eating fortified
foods, taking MVMs, and consuming single vitamins or minerals in large doses,
may lead them to unwittingly exceed the Upper Levels (ULs) of nutrients, which
can be harmful.
Given these safety concerns and the limitations of the available evidence, the
panel advocated for changes in the regulation of dietary supplements — including
MVMs — by the Food and Drug Administration (FDA). Specifically, the panel
recommends that Congress expand FDA’s authority and resources to require manufacturers
to disclose adverse events, to ensure quality production, and to facilitate consumer
reporting of adverse events by including reporting information on dietary supplement
The panel also made several specific recommendations regarding future research,
including but not limited to the following:
- Design and conduct rigorous randomized, controlled trials of the impact of
individual supplements to test their efficacy and safety in prevention of chronic
disease, using well-validated measures
- Build new MVM databases that detail the exact composition of supplements,
update them on a continuous basis, and assure their constant availability to
the research community
- Develop a strategy to support a better understanding of possible interactions
between MVMs and prescribed or over-the-counter medications.
The 13-member panel included experts in the fields of food science and human
nutrition, biostatistics, biochemistry, toxicology, geriatric medicine, family
medicine, pediatrics and pediatric endocrinology, cancer prevention, epidemiology,
disease prevention and health promotion, and consumer protection. A brief biography
on Dr. McGinnis is available at http://www.iom.edu/?id=28194.
A listing of the panel members and their institutional affiliations is included
in the draft conference statement.
In addition to the material presented at the conference by speakers and the
comments and concerns of conference participants presented during discussion
periods, the panel considered pertinent research from the published literature
and the results of a systematic review of the literature commissioned by the
NIH Office of Medical Applications of Research (OMAR). The systematic review
was prepared through the Agency for Healthcare Research and Quality (AHRQ) Evidence-based
Practice Center (EPC) program, by the Johns Hopkins University Evidence-based
Practice Center. The EPCs develop evidence reports and technology assessments
based on rigorous, comprehensive syntheses and analyses of the scientific literature,
emphasizing explicit and detailed documentation of methods, rationale, and assumptions.
The evidence report on Multivitamin/Mineral Supplements and Prevention of Chronic
Diseases is available at http://www.ahrq.gov/clinic/tp/multivittp.htm.
The panel’s statement is an independent report and is not a policy statement
of the NIH or the federal government. The NIH Consensus Development Program,
of which this conference is a part, was established in 1977 as a mechanism to
judge controversial topics in medicine and public health in an unbiased, impartial
manner. NIH has conducted 118 consensus development conferences, and 27 state-of-the-science
(formerly “technology assessment”) conferences, addressing a wide range of issues.
A backgrounder on the NIH Consensus Development Program process is available
Interviews with panel members can be arranged by calling Kelli Marciel at 301-496-4819
or via e-mail to email@example.com.
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