National
Institutes of Health (NIH) consensus and state-of-the-science
statements are prepared by independent panels of health professionals
and public representatives on the basis of 1) the results of a
systematic literature review prepared under contract with the Agency
for Healthcare Research and Quality (AHRQ), 2) presentations by
investigators working in areas relevant to the conference questions
during a 2-day public session, 3) questions and statements from
conference attendees during open discussion periods that are part of
the public session, and 4) closed deliberations by the panel during
the remainder of the second day and the morning of the third. This
statement is an independent report of the panel and is not a policy
statement of the NIH or the federal government.
The statement reflects the panel's assessment of medical knowledge
available at the time the statement was written. Thus, it provides
a "snapshot in time" of the state of knowledge on the conference
topic. When reading the statement, keep in mind that new knowledge
is inevitably accumulating through medical research.
At least half of American adults take a dietary supplement, the
majority of which are multivitamin/multimineral (MVM) supplements. As
more and more Americans seek strategies for maintaining good health
and preventing disease, and as the marketplace offers an increasing
number of products to fulfill that desire, it is important that
consumers have the best possible information to make their choices.
Assessing the available scientific evidence on the benefits of MVM
supplement use for chronic disease prevention, identifying the gaps
in the evidence, and recommending an appropriate research agenda to
meet the shortfalls are subjects considered in this report.
The word vitamine was coined in 1912, as an abbreviated term
meant to capture the notion of important factors in the diet,
or "vital amines." This was preceded more than 150 years earlier
by British navy physician James Lind's discovery—in the first
recorded controlled trial—that citrus juice, a good source of what
was found 2 centuries later to be vitamin C, could prevent scurvy in
sailors. In 1913, the first vitamin was isolated: thiamin, the
deficiency of which caused beriberi. Thirteen vitamins and 15
essential minerals have now been identified as important to human
nutrition.
Large-scale fortification of diets began in the United States with
the addition of iodine to table salt in 1924 to prevent goiter,
followed by the addition of vitamin D to milk in 1933 to prevent
rickets and the addition of thiamin, riboflavin, niacin, and iron to
flour in 1941. Multivitamin/multimineral products providing more than
vitamins A and D became available in pharmacies and grocery stores in
the mid-1930s. In the early 1940s, the first MVM tablet was
introduced.
Although clinical deficiency of vitamins or minerals, other than
iron, is now uncommon in the United States, growth in supplement use
has accelerated rapidly with marketing spurred by claims—some based
on scientific studies—that chronic conditions could be prevented or
treated by supplement use. Annual sales of supplements to Americans
are now reported at about $23 billion, a substantial share of which
is spent on vitamins and minerals.
Because of such widespread use of MVM, increasing public and
medical confusion over apparently contradictory results from
studies, and reports of possible adverse effects from overuse
in certain circumstances, the Office of Dietary Supplements and
the Office of Medical Applications of Research of the NIH convened a
State-of-the-Science Conference on Multivitamin/Mineral Supplements
and Chronic Disease Prevention, held on 15–17 May 2006, in Bethesda,
Maryland. The goal of the conference was to assess the evidence
available on MVM use and outcomes for chronic disease prevention in
the generally healthy population of adults and to make
recommendations for future research. The conference focused on
vitamins and minerals and did not deal with botanicals, hormones, or
other supplements. It also did not address the treatment of vitamin
or mineral deficiencies. Except for considerations of safety, the
conference also did not review issues of primary relevance to
pregnant women or children.
Specifically, the conference explored the following key questions:
1) What are the current patterns and prevalence of the public's
use of MVM supplements? 2) What is known about the dietary nutrient
intake of MVM users versus nonusers? 3) What is the efficacy of
single vitamin/mineral supplement use in chronic disease prevention?
4) What is the efficacy of MVM in chronic disease prevention in the
general population of adults? 5) What is known about the safety of
MVM for the generally healthy population? and 6) What are the major
knowledge gaps and research opportunities regarding MVM use?
During the first 2 days of the conference, experts presented
information on each of the key questions. After weighing the
scientific evidence, including the data presented by the speakers
and a formal evidence report commissioned through AHRQ, an
independent panel prepared and presented a draft of this
state-of-the-science statement addressing the conference questions.
The evidence report prepared for the conference is available at http://www.ahrq.gov/clinic/tp/multivittp.htm.
For the purpose of this statement, the term MVM refers to any
supplement containing 3 or more vitamins and minerals but no
herbs, hormones, or drugs, with each component at a dose less
than the tolerable upper level determined by the Food and Nutrition
Board—the maximum daily intake likely to pose no risk for
adverse health effects. Our review also included studies of the
relationship of single-nutrient supplements and 2-nutrient
supplements to certain disease outcomes. The term primary
prevention refers to preventing the development of disease in a
person who does not have the disease in question. The chronic
conditions assessed include cancer; age-related sensory loss; and
cardiovascular, endocrine, neurologic, musculoskeletal,
gastroenterologic, renal, and pulmonary diseases.
A word is warranted about the nature of the evidence base considered
by the panel. The range of vitamins and minerals of possible
interest was so broad that the conference planning committee
chose to focus the evidence report on nutrients for which the
potential for impact had been most strongly suggested and on
conditions for which supplements were thought to have the most
potential influence.
The planning committee also limited the scope of the evidence
report to consideration of randomized, controlled trials (RCTs),
which are generally considered the gold standard for evidence-based
decision making. These are studies in which participants are
allocated by chance alone to receive or not to receive 1 of 2
or more clinical interventions. For example, while folate
supplementation was initially shown to decrease the risk for
neural tube defects in animal studies, outcome data in nonhuman
models were not considered sufficient evidence on which to base
policy recommendations. At the next level of evidence, observational
studies in humans suggested efficacy of folate supplementation
to prevent such defects. However, these were criticized because
they were not randomized and were potentially subject to bias.
Not until these findings were confirmed by RCTs in humans was
public policy implemented, including fortification of cereal
grains with folate.
An observational study is one in which the exposure or treatment
of interest is not assigned to the participant by the investigator.
Such studies suggested that ß-carotene intake might protect
against the development of some types of cancer. However, RCTs of
ß-carotene supplementation not only showed no benefit, they also
found an increased risk for lung cancer in persons who smoked
cigarettes or who were exposed to asbestos. These examples illustrate
both the risk of relying only on observational studies and the
advantage of RCTs in identifying both benefits and risks of MVM
supplementation.
Limiting the focus of our statement to RCTs has some inherent
limitations, given the potential of other types of studies to
provide important insights. Observational studies, for example,
are particularly useful for generating hypotheses, defining
adverse effects, and documenting long-term treatment consequences.
They are often essential precursors to the well-conducted RCTs
important for policy formation.
Our principal recommendations focus on the compelling research
activities that must be supported to better inform the decisions
that millions of Americans are making each day to use or not to
use MVM supplements to prevent chronic disease. At the same time,
mindful of the constraints of the available evidence base, we have
also taken care not to make premature recommendations about whether
generally healthy Americans should or should not take MVM
supplements. Because of the need for more reliable information on
MVMs, we have made strong recommendations for research and for
increased U.S. Food and Drug Administration (FDA) oversight of the
MVM industry.
1. What
Are the Current Patterns and Prevalence of the Public's Use of MVM
Supplements?
|
More
than half of American adults take dietary supplements in the belief
that they will make them feel better, give them greater energy,
improve their health, and prevent and treat disease. The use of
supplements has been steadily increasing, and growth appears likely
to continue. Currently, users spend more than $23 billion per year on
supplements, and among this supplement-using population, MVM is the
major category of supplements, used by about one third of Americans.
Uncertainty remains in estimating prevalence of use because of
problems defining these products; increasing complexity in the
formulation of supplements, including more non-MVM components and
specialized formulas; and varying frequency of use.
It appears that use is higher among women and among the children
of women who use supplements; in elderly persons; among people
with more education, higher income, healthier lifestyles and
diets, and lower body mass indices; and among residents of the
western United States. Individuals with chronic illnesses or
who are seeking to prevent recurrence of a serious disease (for
example, cancer) also tend to be more frequent users. Many dietary
supplement users perceive their health as better. Conversely,
MVM use is lower among smokers and certain ethnic and racial
groups, such as African-American persons, Hispanic persons, and
Native Americans, while certain Asian ethnic groups appear to have
higher MVM use. Ironically, populations at highest risk for
nutritional inadequacy who might benefit the most from MVM are the
least likely to use such products.
2. What
Is Known about the Dietary Nutrient Intake of MVM Users versus Nonusers?
|
According
to several studies, MVM supplement users (for example, adults,
infants, toddlers age 12 to 24 months, adolescents, and elderly
persons) also tend to have higher micronutrient intakes from their
diet than nonusers. Consequently, MVM users have an increased intake
and are more likely to exceed the upper level. The trend to "fortify"
certain foods not required by law to be fortified with vitamins and
minerals makes calculation of total intake more difficult. A recent
industry report estimates that, in 2005, 65% of Americans used such
fortified foods or beverages, worth $36 billion, and that these sales
are increasing rapidly.
The measurement of dietary vitamin/mineral intake and intake from
supplements is uncertain, which undermines our ability to accurately
assess the distribution of vitamin/mineral intake in the population,
as well as our ability to use observational studies to detect effects
of vitamin/mineral intake on chronic disease. In part, these
uncertainties stem from individuals' difficulty in identifying
correctly what supplements they are actually taking and their
frequency of consumption (for example, many products look alike but
are very different in their composition). Moreover, the lack of
databases of MVM composition limits the ability to translate
supplement intake into amounts of various vitamins and minerals
actually consumed. There are thousands of product labels, vast
differences in the amounts of vitamins/minerals delivered by various
products, and major variability within even the same product over
time and across batches.
These methodologic difficulties should be resolved by 2 actions.
The quality of self-reported data of MVM use should be improved
to enhance accuracy and specificity of reported MVM intake, and
new databases that detail the exact composition of MVM supplements
need to be built and updated on a continuous basis.
3. What
Is the Efficacy of Single Vitamin/Mineral Supplement Use in Chronic
Disease Prevention?
|
Few
high-quality clinical trials have been conducted to determine whether
single-use or paired vitamins/minerals prevent chronic diseases, and
even fewer are generalizable to the U.S. population. In addition,
much of the evidence derives from post hoc analyses for outcomes not
originally chosen as study end points. These studies are reviewed in
the evidence report.
Findings by Vitamin/Mineral
ß-Carotene
Two large trials (1, 2)
designed to test lung cancer prevention with ß-carotene found a
surprising increase in lung cancer incidence and deaths in smokers
and male asbestos workers. There was no effect in preventing a number
of other types of cancer, including gastric, pancreatic, breast,
bladder, colorectal, and prostate cancer as well as leukemia,
mesothelioma, and lymphoma. The overall mortality rate was elevated
in women, but not men, treated with ß-carotene throughout the
intervention and postintervention period. A third large trial (3), in
healthy American men, found no effect of ß-carotene on cancer
except an increased risk for thyroid and bladder cancer. Two
other ß-carotene trials (4, 5)
on prevention of nonmelanoma skin cancer found no effect on
subsequent skin cancer incidence. A large study of healthy American
women also found no effect of ß-carotene on cancer incidence (6).
Four of these ß-carotene trials (2, 3, 5,
7) also evaluated cardiovascular disease (CVD) and found no
benefits. In healthy women, there was a suggestion of increased
stroke risk in 1 study (6)
and an increased risk for CVD in women smokers in the Carotene
and Retinol Efficacy Trial (CARET) (8).
Vitamin A
No trials were found for vitamin A supplementation alone. When
vitamin A was paired with ß-carotene in 1 trial (2),
lung cancer and CVD deaths were increased. When vitamin A was
combined with zinc in another trial, there was no impact on
esophageal or gastric cardia cancer, although noncardia stomach
cancer decreased (9).
Vitamin E
Four trials tested vitamin E. One large study of healthy women,
the Women's Health Study (WHS), recorded decreased cardiovascular
deaths, although there was no effect on incidence of CVD events
(10).
Another trial found a decreased risk for prostate cancer (and a
suggestion of decreased colorectal cancer risk) in male smokers, as
well as a decreased risk for angina and thrombotic stroke (7,
11–14). No other effects were found on other types of cancer.
There was a trend toward increased bleeding, subarachnoid hemorrhage,
and hemorrhagic stroke among male smokers in this study (7), but
in the WHS, no increase in hemorrhagic stroke was seen among women (10).
Another trial (15)
yielded inconclusive results for main cardiovascular end points
because of small numbers and because the trial was stopped
prematurely. Two trials examined development of age-related cataract
(16)
and lens opacity (14),
respectively, and reported no effect of vitamin E
supplementation.
Vitamin B2 and Niacin
One large Chinese trial of vitamin B2 and niacin found a
decreased risk for nuclear cataracts (17).
No effects were found on cortical cataracts, mortality rates, stroke,
upper gastrointestinal dysplasia, or cancer.
Vitamin B6
Two small, short-duration studies of vitamin B6 to prevent
cognitive decline in elderly men and women showed no effects (18).
Folic Acid with or without Vitamin
B12
Multiple studies have shown the effectiveness of folic acid use by
women of childbearing age to prevent neural tube defects in
offspring. Four small, short-duration studies of folic acid, with or
without vitamin B12, to prevent cognitive decline in older
adults found no effects (19).
Selenium
Three trials tested selenium supplementation to prevent cancer. In
2 Chinese trials, selenium decreased liver cancer incidence in
patients at high risk because of either a family history of liver
cancer or hepatitis B exposure status (20).
The reports of these trials, however, lack many important details.
The third selenium trial was conducted in men and women who had a
history of skin cancer (21).
It found no decrease in skin cancer but reported reductions in total
deaths from cancer and in the incidence of lung, prostate, and
colorectal cancer (outcomes the study was not designed to
investigate).
Calcium and Vitamin D
Multiple studies demonstrate that calcium increases bone mineral
density in postmenopausal women but by itself does not decrease
fracture risk. Vitamin D alone does not increase bone mineral
density or decrease fracture risk, but it does work in combination
with calcium to decrease the risk for hip and nonvertebral fractures
in postmenopausal women. Vitamin D and calcium may increase the
risk for kidney stones. The single trial that tested the effect of
calcium supplementation and vitamin D on colorectal cancer risk found
no effect, but the doses may have been inappropriately low (22).
Summary
Few trials of individual or paired vitamins and minerals for the
prevention of chronic disease produced beneficial effects. We found
no evidence to recommend ß-carotene supplements for the general
population and strong evidence to recommend that smokers avoid
ß-carotene supplementation. In combination, calcium and vitamin D
have a beneficial effect on bone mineral density and fracture risk in
postmenopausal women.
On the basis of single studies and analysis of secondary outcomes,
there is a suggestion that selenium may reduce risk for prostate,
lung, and colorectal cancer; that vitamin E may decrease
cardiovascular deaths in women and prostate cancer incidence in male
smokers; and that vitamin A paired with zinc may decrease the risk
for noncardia stomach cancer in rural China. Trials of niacin;
folate; and vitamins B2, B6, and B12
produced no positive effect on chronic disease occurrence in the
general population.
4. What
Is the Efficacy of MVM in Chronic Disease Prevention in the General
Population of Adults?
|
Five
RCTs conducted in the United States, the United Kingdom, China, and
France studied the efficacy of MVM supplements in the primary
prevention of cancer and CVD and in delaying the development or
progression of cataract and age-related macular degeneration (9,
23–27). The 5 studies used combinations of 3 to 7 vitamins,
minerals, or both in 1 or more intervention arms.
We noted some limitations in these studies. In the Chinese study,
while the body mass index of study participants was within the
normal range, there were indications of inadequate intake of
some micronutrients, thus limiting the generalizability of this
study's findings to the U.S. population (9).
Three of these studies addressed eye disease, and all were performed
in patients who had existing eye disease and were seen in
ophthalmology clinics (25–27).
One of these studies had only 71 patients and included several
supplements other than vitamins and minerals in the intervention (27). A
binational study of cataracts had different entry criteria in each
country (25).
Findings by Disease
Cancer
Both trials that examined cancer end points found a reduction in
cancer incidence, mortality, or both. In China, overall cancer
incidence and mortality rates were significantly reduced, as
were incidence and mortality rates for the 2 leading types of
cancer, esophageal and gastric, in an arm of the study that
included vitamin E, ß-carotene, and selenium (9).
The decrease in esophageal cancer emerged as a statistically
significant finding only after many years of follow-up. Another
arm of the study, on zinc and vitamin A, was associated with a
reduction in noncardia gastric cancer, although other gastric cancer
and esophageal cancer were not reduced. In France, an intervention
consisting of vitamin E, selenium, vitamin C, ß-carotene, and zinc
was associated with a reduction in overall cancer incidence in men
only, but no individual type of cancer was clearly reduced (23).
Overall mortality rates in men were also lower in the intervention
group. No effect was seen in women. In China, younger persons in the
intervention group had a lower incidence of esophageal cancer, but
older persons had a higher incidence associated with treatment. Among
men in the French study with normal prostate-specific antigen levels,
the intervention was associated with a lower incidence of prostate
cancer but prostate cancer incidence was higher among men with high
prostate-specific antigen levels at baseline (24).
CVD
None of the reviewed studies showed any benefits or harm related
to CVD resulting from MVM use in the studied populations.
Cataract
Mixed results emerged from studies in which cataract progression
was the targeted outcome. Only modest and inconsistent effects
were found in the 2 studies that reported any benefit (25,
26).
Age-Related Macular Degeneration
One study showed less progression of intermediate-stage age-related
macular degeneration in persons receiving vitamins C and E,
ß-carotene, and zinc (26).
Summary
The uncertainty resulting from these trials suggests that multivitamin
trials are unlikely to lead to generalizable knowledge. They
cannot distinguish between the effects of individual components;
they are likely to be contaminated by MVM use in the placebo
group; they have a weaker biological basis than single-vitamin
or single-mineral studies; they require very large sample sizes;
and they will become outdated from a public health perspective
because of the changing composition of commonly used MVMs.
There is evidence from 1 well-designed trial to consider use of
antioxidants and zinc in adults with intermediate-stage age-related
macular degeneration. Some suggestive evidence points to a possible
benefit of selenium, vitamin E, or both in cancer prevention,
especially in men. However, studies have also identified subgroups
of the population whose cancer risk might increase with such
supplementation. Trials currently in progress (for example, the
Selenium and Vitamin E Cancer Prevention Trial [SELECT] and the
Physicians' Health Study II) should help determine the actual
benefits and harms of such supplementation.
5. What
Is Known about the Safety of MVM for the Generally Healthy Population?
|
Most
people assume that the ingredients in MVM supplements are safe. There
is evidence, however, that certain ingredients in MVM supplements can
produce adverse effects, including reports from RCTs that noted
excess lung cancer occurring in asbestos workers and smokers
consuming ß-carotene. In addition, esophageal cancer excess was found
with long-term follow-up of older Chinese patients treated with
selenium, ß-carotene, and vitamin E supplements (9).
There was also evidence for gender difference in patterns of lung
cancer and CVD risk related to ß-carotene. In another study, patients
with elevated prostate-specific antigen levels at baseline who were
receiving an MVM intervention had higher incidence of prostate
cancer (24).
Vitamin D and calcium may increase the risk for kidney stones for
certain people. These data raise safety questions both in general and
in special populations. Although these studies are not definitive,
they do suggest possible safety concerns that should be monitored for
primary components of multivitamins.
The RCTs and observational studies on vitamin and mineral supplements
have provided little information on the safety of single-vitamin,
single-mineral, or MVM dietary supplements. Safety assessments
were often limited to adverse reports from patients who dropped
out of trials. The RCTs did not include assessments of well-known
potential adverse end points. Issues that have not been adequately
addressed include but are not limited to reproducibility of the
MVM manufacturing process, characterization of the vitamin mix,
demonstration of the absence of contaminants, stability, and
interactions with other nutrients or drugs.
There is potential for adverse effects in individuals consuming
dietary supplements that are above the upper level. This can
occur not only in individuals consuming high-potency single-nutrient
supplements but also in individuals who consume a healthy diet
rich in fortified foods in combination with MVM supplements.
Furthermore, by law, the listing of ingredient amounts on nutrient
supplement labels is the minimum content; thus, higher intakes
are probable. Data from prospective studies have shown that
individuals taking MVM dietary supplements improved their nutritional
adequacy with respect to several nutrients but also increased
the proportion of their intakes above the upper level for several
of the supplemented nutrients. With the strong trends of increasing
MVM and other dietary supplement consumption, and the increasing
fortification of the U.S. diet, we are concerned that a growing
proportion of the population may be consuming levels considerably
above the upper level, thus increasing the possibility of adverse
effects.
The FDA has insufficient resources and legislative authority to
require specific safety data from dietary supplement manufacturers or
distributors before or after their products are made available to the
public. This lack of regulation exists despite the reality that many
of the ingredients of MVMs would be subject to premarket approval if
they were marketed as food additives and that in some cases the
ingredients possess biological activities similar, if not identical,
to those found in medications. The 1994 Dietary Supplement Health and
Education Act (DSHEA) assumed that history of use of a given
supplement was evidence for safety, thus grandfathering in all
supplements on the market before the legislation. However, use of
nutrients in foods and supplements in the United States is changing,
and we are concerned that public safety cannot be assured. Adverse
events from MVMs appear with some frequency in both the reports of
the American Association of Poison Control Centers and the FDA's
MedWatch system.
We found the primary recommendation of the 2005 Institute of
Medicine committee report on dietary supplements compelling:
"[T]he regulatory mechanisms for monitoring the safety of dietary
supplements, as currently defined by DSHEA, [should] be revised.
The constraints imposed on FDA with regard to ensuring the absence
of unreasonable risk associated with the use of dietary supplements
make it difficult for the health of the American public to be
adequately protected." The FDA should have the authority to
better inform consumers and health professionals regarding the
existence of upper levels as well as the possible risks of exceeding
those levels; develop a formal, mandatory adverse event reporting
system for dietary supplements; and mandate provision of a MedWatch
toll-free telephone number or Web site on product labels to
facilitate reporting of adverse events. Furthermore, we recommend
that health care professionals, consumers, and manufacturers
use the FDA MedWatch adverse event reporting system to report
adverse events associated with the use of dietary supplements.
Finally, we recommend that Congress revise and update the law
to reflect current knowledge.
6. What
Are the Major Knowledge Gaps and Research Opportunities regarding MVM Use?
|
This
review of the state of the science has identified important gaps in
knowledge about the relationship between MVM use and chronic disease
prevention in generally healthy adults. These deficiencies are
attributable to shortcomings in data quality and a paucity of
rigorously designed and conducted studies, especially RCTs. Hence,
this report emphasizes the need and rationale for rigorous,
state-of-the-art, methodologically and technologically
forward-looking research to bridge these gaps. We strongly recommend
the following actions.
1. Elicit more accurate information from individuals to improve
the quality of self-reported data on MVM use. Capitalize on new
electronic technologies, design and employ improved questionnaires,
and develop new dietary and MVM recall methods, all to enhance
accuracy and specificity of reported MVM intake.
2. 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. A national database,
such as that developed and maintained by the U.S. Department of
Agriculture for food composition, will be a major improvement for
determining potential impact, benefits, and harms of MVM.
3. Determine the most effective means to translate scientific
information and improve communication about dietary supplements
among consumers, health care providers, industry, scientists,
and policymakers.
4. Develop a strategy to support the study of possible interactions
of MVMs with nutrients or prescribed and over-the-counter
medications.
5. Study populations that reflect the diversity of the United
States ethnically, economically, and by age and sex. Focus on
population segments previously underrepresented and on individuals
at increased risk for chronic disease.
6. Capitalize on the rapidly progressing state of biomedical
science to develop and apply techniques for assessing the basic
biological mechanisms by which supplements may modify disease
risks, for example, nutritional genomics, molecular imaging,
and systems biology network approaches. The resulting knowledge
may identify important new biomarkers, early in the disease
process, that may inform observational studies and RCTs.
7. Design and conduct rigorous RCTs of the impact of individual
supplements (or paired supplements, when biologically plausible)
to test their efficacy and safety in prevention of chronic disease,
using well-validated measures. Select the vitamins and minerals
to be studied on the basis of their biological plausibility and
outcomes of appropriate observational and pilot studies. Include in
trials the most modern and validated biomarkers of exposure,
bioavailability intermediary metabolism, and early disease. When
possible, incorporate relevant genetic polymorphisms and other
indices of individual physiologic characteristics into trial design.
Randomized, controlled trials should employ such cost-effective and
innovative methods as fractional factorial designs, which will permit
the simultaneous evolution of multiple single supplements and their
low-order interactions. Assure sufficient trial duration of both
observational studies and RCTs during intervention and follow-up to
determine important outcomes that may inform public policy
decisions.
Use
of MVMs has grown rapidly over the past several decades, and dietary
supplements are now used by more than half of the adult population in
the United States. In general, MVMs are used by individuals who
practice healthier lifestyles, thus making observational studies of
the overall relationship between MVM use and general health outcomes
difficult to interpret. Despite the widespread use of MVMs, we still
have insufficient knowledge about the actual amount of total
nutrients that Americans consume from diet and supplements. This is
at least in part due to the fortification of foods with these
nutrients, which adds to the effects of MVMs or single-vitamin or
single-mineral supplements. Historically, fortification of foods has
led to the remediation of vitamin and mineral deficits, but the
cumulative effects of supplementation and fortification have also
raised safety concerns about exceeding upper levels. Thus, there
is a national need to improve the methods of obtaining accurate
and current data on the public's total intake of these nutrients
in foods and dietary supplements.
In systematically evaluating the effectiveness and safety of MVMs
in relation to chronic disease prevention, we found few rigorous
studies on which to base clear conclusions and recommendations. Most
of the studies we examined do not provide strong evidence for
beneficial health-related effects of supplements taken singly, in
pairs, or in combinations of 3 or more. Within some studies or
subgroups of the study populations, there is encouraging evidence of
health benefits, such as increased bone mineral density and decreased
fractures in postmenopausal women who use calcium and vitamin D
supplements. However, several other studies also provide disturbing
evidence of risk, such as increased lung cancer risk with ß-carotene
use among smokers.
The current level of public assurance of the safety and quality of
MVMs is inadequate, given the fact that manufacturers of these
products are not required to report adverse events and the FDA has no
regulatory authority to require labeling changes or to help inform
the public of these issues and concerns. It is important that the
FDA's purview over these products be authorized and implemented.
Finally, the present evidence is insufficient to recommend either
for or against the use of MVMs by the American public to prevent
chronic disease. The resolution of this important issue will
require advances in research and improved communication and
collaboration among scientists, health care providers, patients,
the pharmaceutical and supplement industries, and the public.
Appendix 1: NIH State-of-the-Science Panel on Multivitamin/Mineral
Supplements and Chronic Disease Prevention
|
J.
Michael McGinnis, MD, MPP (Panel and Conference Chairperson),
Institute of Medicine, The National Academies, Washington, DC;
Diane F. Birt, PhD, Department of Food Science and Human Nutrition,
Center for Research on Botanical Dietary Supplements, and College
of Agriculture and College of Human Sciences, Iowa State University,
Ames, Iowa; Patsy M. Brannon, PhD, RD, Division of Nutritional
Sciences, Cornell University, Ithaca, New York; Raymond J. Carroll,
PhD, Department of Statistics, Texas A&M University, College
Station, Texas; Robert D. Gibbons, PhD, Center for Health Statistics,
University of Illinois at Chicago, Chicago, Illinois; William
R. Hazzard, MD, Department of Medicine, Division of Gerontology
and Geriatric Medicine, University of Washington, VA Puget Sound
Health Care System, Seattle, Washington; Douglas B. Kamerow,
MD, MPH, Georgetown University and RTI International, Washington,
DC; Bernard Levin, MD, University of Texas M.D. Anderson Cancer
Center, Houston, Texas; James M. Ntambi, PhD, Departments of
Biochemistry and Nutritional Sciences, University of
Wisconsin–Madison, Madison, Wisconsin; Nigel Paneth, MD, MPH, College
of Human Medicine, Michigan State University, East Lansing,
Michigan; Douglas Rogers, MD, Section of Pediatric and Adolescent
Endocrinology, The Cleveland Clinic, Cleveland, Ohio; Audrey F.
Saftlas, PhD, MPH, Department of Epidemiology, The University of Iowa
College of Public Health, Iowa City, Iowa; William Vaughan,
Consumer's Union, Washington, DC.
Appendix 2
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Speakers
Anthony J. Alberg, PhD, MPH, Department of Biostatistics,
Bioinformatics, and Epidemiology, Hollings Cancer Center, Medical
University of South Carolina, Charleston, South Carolina; Bruce N.
Ames, PhD, University of California, Berkeley, and Children's
Hospital Oakland Research Institute, Oakland, California; Diane
Benford, PhD, Chemical Safety Division, Food Standards Agency,
London, United Kingdom; Benjamin Caballero, MD, PhD, Center for
Human Nutrition, Johns Hopkins Bloomberg School of Public
Health, Baltimore, Maryland; Allen Dobson, PhD, The Lewin Group,
Falls Church, Virginia; Peter Greenwald, MD, DrPH, Division of
Cancer Prevention, National Cancer Institute, National Institutes
of Health, Rockville, Maryland; Robert P. Heaney, MD, Department
of Medicine, Creighton University, Omaha, Nebraska; Han-Yao
Huang, PhD, MPH, Department of Epidemiology, Johns Hopkins Bloomberg
School of Public Health, Sidney Kimmel Comprehensive Cancer
Center, Johns Hopkins School of Medicine, Baltimore, Maryland;
Suzanne Murphy, PhD, RD, Cancer Research Center of Hawaii, University
of Hawaii, Honolulu, Hawaii; Roy M. Pitkin, MD, University of
California, Los Angeles, La Quinta, California; Ross L. Prentice,
PhD, Division of Public Health Sciences, Fred Hutchinson Cancer
Research Center, Seattle, Washington; Cheryl L. Rock, PhD, RD,
Family and Preventive Medicine, Cancer Prevention and Control
Program, University of California, San Diego, La Jolla, California;
Irwin H. Rosenberg, MD, Jean Mayer U.S. Department of Agriculture
Human Nutrition Research Center on Aging, Tufts University,
Boston, Massachusetts; Johanna M. Seddon, MD, ScM, Epidemiology
Unit, Department of Ophthalmology, Massachusetts Eye and Ear
Infirmary, Boston, Massachusetts; A. Elizabeth Sloan, PhD, Food
Technology, Functional Foods & Nutraceuticals, and
Flavor & The Menu, Escondido, California; Meir J.
Stampfer, MD, DrPH, Departments of Epidemiology and Nutrition,
Harvard School of Public Health and Harvard Medical School, Boston,
Massachusetts; Maret Traber, PhD, Linus Pauling Institute, Oregon
State University, Corvallis, Oregon; Jason J.Y. Woo, MD, MPH,
Division of Dietary Supplement Programs, Office of Nutritional
Products, Labeling, and Dietary Supplements, Center for Food Safety
& Applied Nutrition, U.S. Food and Drug Administration, College
Park, Maryland; Elizabeth Yetley, PhD, Office of Dietary
Supplements, National Institutes of Health, Bethesda, Maryland.
Planning Committee
Johanna Dwyer, DSc, RD, and Paul M. Coates, PhD (Planning Committee
Co-Chairpersons), Office of Dietary Supplements, National
Institutes of Health, Bethesda, Maryland; Mayada Akil, MD, Office of
Science Policy and Program Planning, National Institute of Mental
Health, National Institutes of Health, Bethesda, Maryland; David
Atkins, MD, MPH, Center for Outcomes and Evidence, Agency for
Healthcare Research and Quality, U.S. Department of Health and Human
Services, Rockville, Maryland; Barbara A. Bowman, National Center
for Chronic Disease Prevention and Health Promotion, Centers for
Disease Control and Prevention, Atlanta, Georgia; Elsa A. Bray,
Office of Medical Applications of Research, National Institutes
of Health, Bethesda, Maryland; Emily Chew, MD, Division of
Epidemiology and Clinical Research, National Eye Institute, National
Institutes of Health, Bethesda, Maryland; Gerald Combs Jr., PhD,
Grand Forks Human Nutrition Research Center, U.S. Department of
Agriculture, Grand Forks, North Dakota; Margaret Coopey, RN, MGA,
MPS, Center for Practice and Technology Assessment, Agency for
Healthcare Research and Quality, U.S. Department of Health and Human
Services, Rockville, Maryland; Cindy D. Davis, PhD, Nutritional
Science Research Group, National Cancer Institute, National
Institutes of Health, Bethesda, Maryland; James Everhart, MD, MPH,
Epidemiology and Clinical Trials Branch, Division of Digestive
Diseases and Nutrition, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes of Health, Bethesda,
Maryland; Judith A. Finkelstein, PhD, Neuroscience and
Neuropsychology of Aging Program, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland; Gilman D. Grave,
MD, Endocrinology, Nutrition, and Growth Branch, National Institute
of Child Health and Human Development, National Institutes of Health,
Bethesda, Maryland; Laura Kettel Khan, PhD, Chronic Disease
Nutrition, Division of Nutrition and Physical Activity, Centers for
Disease Control and Prevention, Atlanta, Georgia; Marguerite A.
Klein, National Center for Complementary and Alternative
Medicine, National Institutes of Health, Bethesda, Maryland; Barnett
S. Kramer, MD, MPH, Office of Medical Applications of Research,
National Institutes of Health, Bethesda, Maryland; Molly Kretsch,
PhD, National Program Leader for Human Nutrition, Agriculture
Research Service, U.S. Department of Agriculture, Beltsville,
Maryland; Catherine Loria, PhD, National Heart, Lung, and Blood
Institute, National Institutes of Health, Bethesda, Maryland;
Kelli K. Marciel, MA, Office of Medical Applications of Research,
National Institutes of Health, Bethesda, Maryland; J. Michael
McGinnis, MD, MPP, The Robert Wood Johnson Foundation, Washington,
DC; Joan A. McGowan, PhD, Musculoskeletal Diseases Branch, National
Institute of Arthritis and Musculoskeletal and Skin Diseases,
National Institutes of Health, Bethesda, Maryland; Linda D.
Meyers, PhD, Food and Nutrition Board, Institute of Medicine,
The National Academies, Washington, DC; Lata S. Nerurkar, PhD,
Office of Medical Applications of Research, National Institutes
of Health, Bethesda, Maryland; Malden C. Nesheim, PhD, Division
of Nutritional Sciences, College of Human Ecology, Cornell
University, Ithaca, New York; Lester Packer, PhD, Department of
Molecular Pharmacology and Toxicology, University of Southern
California School of Pharmacy, Los Angeles, California; Irwin H.
Rosenberg, MD, Jean Mayer U.S. Department of Agriculture Human
Nutrition Research Center on Aging, Tufts University, Boston,
Massachusetts; Susan Rossi, PhD, MPH, Office of Medical Applications
of Research, National Institutes of Health, Bethesda, Maryland; John
Paul SanGiovanni, ScD, Division of Epidemiology and Clinical
Research, National Eye Institute, National Institutes of Health,
Bethesda, Maryland; Paul A. Sheehy, PhD, National Institute of
Neurological Disorders and Stroke, National Institutes of Health,
Rockville, Maryland; Pamela Starke-Reed, PhD, Division of Nutrition
Research Coordination, National Institutes of Health, Bethesda,
Maryland; Amy F. Subar, PhD, MPH, RD, National Cancer Institute,
National Institutes of Health, Rockville, Maryland; Anne Thurn,
PhD, Evidence-Based Review Program, Office of Dietary
Supplements, National Institutes of Health, Bethesda, Maryland; Paula
R. Trumbo, PhD, Division of Nutrition Programs and Labeling,
U.S. Food and Drug Administration, College Park, Maryland.
Conference Sponsors
Office of Dietary Supplements (Paul M. Coates, PhD, Director);
Office of Medical Applications of Research (Barnett S. Kramer,
MD, MPH, Director).
Conference Cosponsors
National Cancer Institute (Andrew C. von Eschenbach, MD, Director);
National Center for Complementary and Alternative Medicine (Stephen
E. Straus, MD, Director); National Eye Institute (Paul A. Sieving,
MD, PhD, Director); National Institute on Aging (Richard J.
Hodes, MD, Director); National Institute of Arthritis and
Musculoskeletal and Skin Diseases (Stephen I. Katz, MD, PhD,
Director); National Institute of Child Health and Human Development
(Duane Alexander, MD, Director); National Institute of Diabetes and
Digestive and Kidney Diseases (Griffin P. Rodgers, MD, Acting
Director).
Conference Partners
Centers for Disease Control and Prevention (Julie Louise Gerberding,
MD, MPH, Director); U.S. Food and Drug Administration (Andrew
C. von Eschenbach, MD, Acting Commissioner); U.S. Department of
Agriculture (Mike Johanns, JD, Secretary).
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