by Tim Wood, Ph.D., Executive
Vice President, R and D, USANA Health Sciences, Inc.
EXECUTIVE SUMMARY
The value of
nutritional supplements in promoting and protecting human health is intensely debated.
Some argue that supplements provide a convenient and effective means for
supplying the optimal intakes of essential nutrients that people need for good
health. Others argue that there is no conclusive evidence that supplements
provide any true health benefits at all. The latter argument has been bolstered
over the past several years by a steady stream of negative research reports
published in leading medical journals.
This paper
examines the supplement debate and questions some of the recent evidence
suggesting that nutritional supplements are ineffective and unsafe. It is
argued that much of the current controversy and negativity surrounding
nutritional supplements results from inappropriate use of a pharmaceutical,
acute-care model in the clinical evaluation of nutritional products; products
whose real value is in preventing rather than treating disease. As a result of
this mismatch, nutritional supplements are often tested inappropriately,
results of studies are interpreted less than objectively, and valid but
non-clinical evidence of benefit is often discounted or ignored.
As a case in
point, I focus on vitamin E supplements and their role in preventing heart
disease. But the central tenets raised in this paper pertain to nutritional
supplements in general, and to much broader issues surrounding the field of
primary prevention as a whole. We now spend about $2.0 trillion dollars
annually on healthcare in the US. Ninety-eight percent of this spending goes to
the treatment of injuries and disease. And, the lion’s share goes to the
treatment of chronic degenerative diseases (e.g. heart disease, cancer, and
type 2 diabetes), the leading causes of premature death and disability in our
society. Only 2% of our healthcare dollars are spent on primary prevention;
measures designed to keep healthy people healthy. This despite the fact that
most chronic degenerative diseases are highly (60-90%) preventable.
In this
light, increased emphasis on primary prevention holds tremendous potential for
improving the effectiveness of our healthcare system. Most Americans have the
opportunity to add years of health to their lives by embracing prudent
lifestyle strategies and habits over the long-term. Clearly, such strategies
need to be broad-based, encompassing diet, nutrition, exercise, stress
management, and the avoidance of harmful habits like smoking. And just as
clearly, a program of responsible supplementation, designed to compliment
healthy eating habits and provide the advanced levels of essential vitamins,
minerals and antioxidants required for lifelong health, can play an important
role in this endeavor. The science, when approached broadly with an open mind,
is convincing on this point.
ABOUT THE AUTHOR
Tim Wood is
Executive Vice President of Research and Development for USANA Health Sciences,
Inc. He received his Ph.D. in the Biological Sciences from Yale University in
1980. He also holds an MBA from the Gore School of Business. Dr. Wood joined
USANA Health Sciences in 1996 and has overseen the company’s Research and
Development, Quality Assurance, and International Regulatory efforts since that
time.
INTRODUCTION
The value of
nutritional supplements in promoting and protecting human health is intensely
debated. Some argue that supplements provide a convenient and effective means
for supplying, on a daily basis, the optimal intakes of essential nutrients
that people need for good health. Others argue that there is no conclusive
evidence that supplements provide any true health benefits at all. The latter
argument has been bolstered over the past several years by a steady stream of
negative research reports published in leading medical journals. Several such
papers have concluded that antioxidants and B vitamin supplements are
ineffective at reducing the risks of heart disease and cancer (Lee et al, 2006;
Kirsh et al, 2006;Zoungas et al, 2006). Others have reported that calcium and
vitamin D supplements provide at best incomplete protection against
osteoporosis (c.f. Jackson et al, 2006). Still others have questioned the
safety of nutritional supplements (c.f. Bjelakovic et al, 2004, Bairati et al,
2005; Miller et al, 2005). Each time such studies appear, newspaper headlines
blare “Supplements Proven to Be Snake Oil” or “Vitamin E May Be Deadly”.
Morning talk shows feature doctors and alternative practitioners who argue over
the latest findings. Sadly, the public grows more confused about what to
believe concerning the role of nutrition and nutritional supplements in health.
This paper
examines the supplement debate and questions some of the recent evidence
suggesting that nutritional supplements are ineffective and unsafe. I argue
that much of the current controversy and negativity surrounding the benefits of
nutritional supplements result from inappropriate use of a pharmaceutical,
acute-care model in the clinical evaluation of nutritional products - products
whose real value is in preventing rather than treating disease. It is further
argued that while the case against supplements may be evidence-based, the relevance
of much of that evidence is questionable.
Healthcare versus Disease Management
This year,
Americans will spend $2 trillion on healthcare (Borger et al, 2006). This
enormous sum represents about $7,000 in healthcare spending for every man,
woman, and child in the US. It also equates to a spending rate of more than
$60,000 per second…and that’s 24-7-365. How is this money being spent?
Ninety-eight percent goes to the treatment of injuries and disease, and the
lion’s share of this goes to the treatment of chronic degenerative diseases
such as heart disease, cancer, type 2 diabetes, osteoporosis, Alzheimer’s
disease, and the like. Today, these are the leading causes of premature death
and disability in our society (CDC, 2002).
In
comparison, only 2% of our healthcare dollars are spent on primary prevention -
measures designed to keep healthy people healthy. This despite the fact that
all of the chronic degenerative diseases listed above are highly preventable.
It is estimated, for example, that 60-70% of the current cases of heart disease
could have been prevented through improved nutrition, better exercise habits,
avoidance of smoking, and the adoption of other healthy lifestyle habits (Koop,
2002). Similar statistics apply to the prevention of cancer, stroke, cataracts,
osteoporosis, and macular degeneration (c.f. Michel, 2002; Rosenthal, 2002).
Type 2 diabetes is thought to be 90% preventable, largely through improved
nutrition and exercise (Hu et al, 2001).
This lopsided
pattern in spending is a clear reflection of today’s dominant healthcare
paradigm; one that focuses on disease treatment rather than disease prevention.
Ours is a reactive as opposed to proactive healthcare system. We wait for
people to develop chronic illnesses, and then we spend enormous amounts of
money treating those illnesses. The alternative, a focus on primary prevention
and an investment in keeping healthy people healthy, receives lip service, but
is largely ignored in practice. Clearly our healthcare system is less about
caring for health and more about managing disease.
It is also a
system of high-tech, acute-care medicine based on the promise of powerful, fast
acting drugs and surgeries that produce therapeutic results in hours, days or
weeks. We spend tens of billions of dollars every year on medical research in a
quest to develop ever more effective diagnostics, drugs, drug delivery systems,
implants, and surgeries (Meeks, 2002). And we spend billions more on patenting
these technologies. Why? Because our healthcare system is lucrative. It is no
accident that we spend $2 trillion annually on healthcare in the US, that
pharmaceutical companies rank among the most profitable in America, and that
our healthcare costs are rising at near double-digit rates that surpass
inflation and growth in our Gross Domestic Product (Polich, 2005; Borger et al,
2006).
To be sure,
acute, treatment-based medicine is useful and effective in dealing with urgent
medical conditions such as trauma, infection, or incipient heart attacks.
However, our almost singular focus on reactive, acute-care medicine also
carries serious limitations, costs and liabilities. This approach is not
particularly effective in dealing with chronic degenerative diseases like heart
disease, cancer and osteoporosis. After decades of research, we still have no
reliable cures for these diseases. We can treat them and manage them, but we
cannot cure them. Moreover, this approach is expensive, both in dollars spent
and in years of health lost to premature death and disability. Chronic diseases
rob far too many Americans of their health, independence, and quality of life
far too early (Michaud et al, 2001). Finally, acutely acting medicines and
surgeries have many undesirable side effects. Every year, prescription drugs -
taken as prescribed - injure more than 1.5 million Americans so severely that
they require hospitalization. One hundred thousand others are killed by
prescription drugs, making such medicines a leading cause of death in the
United States (Lazarou et al, 1998).
A Vital Role for Primary Prevention
Is there a
better way? I would argue that rebalancing our healthcare system to include a
larger emphasis on primary prevention is an essential step. I would further
argue that we can act now. We know enough today about the principles of primary
prevention, and about the basics of a healthy lifestyle (nutrition, exercise,
stress management, avoidance of smoking, etc) to implement significant
improvements without delay. And I would argue that nutritional supplementation
can play a vital role in this arena.
The research
is clear. Diet and nutrition play key roles in supporting good health (WHO,
2003). It is equally clear that Americans, as a whole suffer from generally
poor nutritional habits (Frazao, 1999). As a nation we are overfed and
undernourished. Two thirds of American adults are overweight or obese (Flegal
et al, 2002; Hedley et al, 2004), and high percentages of us are chronically
deficient for one or more of the essential vitamins, minerals and antioxidants
(FASEB, 1995).
Some would
argue that this problem lies in poor diet alone; that all we need to do is eat
better. Clearly, a healthy well balanced diet is an absolute foundation for any
program of optimal nutrition. But is a healthy diet enough? Can we obtain
“optimal levels” of the essential vitamins, minerals, and antioxidants on a
routine basis from diet alone? Many, including myself, argue “no”; that optimal
intakes of the essential nutrients, intakes required to optimize health and
minimize the risk of chronic diseases, are significantly higher than the amounts
that can be obtained routinely from food (and significantly higher than the
current RDA’s). In my view, optimal nutrition is best achieved through a
combination of a healthy well balanced diet plus a responsible program of
nutritional supplementation. In my view, a healthy diet and nutritional
supplements are not mutually exclusive. This is not an “either-or” proposition.
It is an “and” proposition.
Is there
substantial scientific evidence to support this notion? Yes. There are hundreds
of scientific studies showing that regular and responsible use of nutritional
supplements can benefit people’s health both in the short- and long-terms
(Dickinson, 1998). Have all supplement studies shown positive benefits, and are
all the findings consistent? No. As with any body of exploratory research,
negative findings and inconsistent results appear in the mix. But when the
science is reviewed in full, the evidence for defined benefits is convincing.
There are scores of studies supporting the role of calcium and vitamin D
supplementation for promoting strong, mineral-rich bones and reducing the risk
and progression of osteoporosis (c.f. Chevalley et al, 1994; Dawson-Hughes et
al, 1997; Chapuy et al, 1994; Recker et al, 1996; Larsen et al, 2004). There
are scores of studies supporting the use of B vitamin supplements for reducing
the risks of some birth defects and lowering some markers of heart disease
(c.f. MRC Vitamin Study Research Group, 1991; Berry et al, 1999; Czeizel and
Dudas, 1992; Lobo et al, 1999; Woodside et al, 1998; Bronstrup et al, 1998;
Schnyder et al, 2002). In addition, numerous studies link antioxidant
supplementation to reduced incidence of cataracts, heart disease, and some
cancers (Jacques et al, 1997; Mares-Perlman et al, 2000; AREDS Research Group, 2001;
Stampfer et al, 1993; Stephens et al, 1996; Clark et al, 1998; Meyer et al,
2005). Fish oil supplements have been shown to support improved cardiovascular
health and neural development (GISSI-Prevenzione Investigators, 1999; Bucher et
al, 2002; Studer et al, 2005; Carlson et al, 1993; Birch et al, 2000). And the
list goes on.
Why then, is
the role of nutritional supplementation in healthcare so hotly debated?
Clearly, this is a complex issue, but I believe that much of this debate stems
from a fundamental incompatibility between our current healthcare paradigm
(acute, disease-focused medicine) and the basic tenets of primary prevention.
Moreover, current approaches to medical research, geared largely toward the
evaluation of acute, fast-acting medicines and surgeries, are in most cases
inappropriate for the study of long-term primary preventive measures like
nutritional supplementation. As a result, nutritional supplements are often
tested inappropriately, results of studies are interpreted less than objectively,
and valid but non-clinical evidence of benefit is often discounted or ignored.
Conventional Medicine Looks at Vitamin
E: A Case in Point
These
challenges are perhaps most evident in the scientific literature concerning
vitamin E supplements and heart disease. In the early 1990’s, a large body of
scientific evidence pointed to oxidative stress as a disease process in the
onset and progression of atherosclerosis. This same research suggested in
various ways that antioxidants like vitamin E might be important in preventing
this disorder. Numerous epidemiological (population based) studies, many
involving tens of thousands of subjects, concluded with consistency that people
who consumed high amounts of vitamin E through diet and supplements were at 30-50%
lower risk for heart attacks or death due to heart disease relative to those
people who consumed minimal amounts of vitamin E (Stampfer et al, 1993; Rimm et
al, 1993; Losonczy et al, 1996; Kushi et al, 1996; Meyer et al, 1996).
Typically, the levels of vitamin E that were protective totaled hundreds of
International Units per day, many times higher than the Recommended dietary
Allowance (RDA).
A. An Early Clinical Evaluation
To further
test this protective effect, clinical research on vitamin E supplementation and
heart disease was undertaken at several centers. In January 2000, results from
one of the first such studies were published in the New England Journal of
Medicine (Yusuf et al, 2000). The Heart Outcomes Prevention Evaluation (HOPE)
involved over 9,500 subjects 55 years of age or older who were at high risk for
cardiovascular events because they had advanced cardiovascular disease,
diabetes, or similar risk factors. Over half, in fact, had had a previous heart
attack. Half the subjects in the trial were assigned at random to take 400 IU
daily of natural-source vitamin E. The remainder were given placebo capsules.
Average follow-up was 4.5 years, during which time, subjects were monitored for
primary and secondary cardiovascular events such as nonfatal heart attacks,
stroke, angina, and death.
Results of
the HOPE study showed that, after 4.5 years, there were no significant
differences in the numbers of heart attacks, strokes, reports of angina, or
deaths due to heart disease between the treatment and placebo groups. The
authors of the paper correctly and appropriately concluded that “in patients at
high risk [emphasis added] for cardiovascular events, treatment with vitamin E
for 4.5 years has no apparent effect on cardiovascular outcomes”.
Unfortunately,
while the conclusions reached by the authors were appropriate, much of the
editorializing in the medical and popular press was not. Instead, headlines and
sound bites touted the results of the HOPE study as conclusive proof that
vitamin E supplements provided no benefits for cardiovascular health. Others
declared the findings as “the last nail in the coffin for vitamin E”.
HOPE is only
one of several clinical trials to have evaluated the efficacy of vitamin E in
preventing cardiovascular events in high-risk groups. While two such trials
showed significant benefit (Stephens et al, 1996; Boaz et al, 2000), the
majority, like the HOPE study, produced disappointing results
(GISSI-Prevenzione Investigators, 1999; Collaborative Group of the PPP, 2001).
Does this mean that vitamin E is ineffective as a preventive agent? In
answering this question, two important issues need to be addressed.
First, the
standard model for clinical research requires testing one remedy (one drug) at
a time, so that the true, isolated effect of that drug can be identified and
measured. This is good science. However, it is not necessarily appropriate in
the field of preventive nutrition.
Humans
require a full range of some 25-plus essential vitamins, minerals, and
antioxidants, in proper amounts and balances, to support good health. This is
because vitamins and minerals work in teams to support, for example, robust
energy metabolism and protein synthesis. Similarly, antioxidants work most
effectively in groups and networks (Packer and Obermuller-Jevic, 2002), each
playing a unique role in channeling and quenching the chain-like series of
oxidative reactions that can result from a single oxidative event. As such,
high-doses of a single nutrient represent an incomplete and inappropriate
approach to boosting overall antioxidant protection. This would be analogous to
testing the hypothesis that broccoli has cancer-preventive properties by
putting people on an all- broccoli diet. It’s not likely to work, and it
carries the risk of creating nutrient imbalances, unwanted side effects, and
experimental artifacts.
Second, an
important distinction needs to be drawn between primary and secondary
prevention. Primary prevention involves keeping healthy people healthy. It is
about preventing the development of disorders like heart disease in the first
place. Secondary prevention is about preventing further progression of a
disease that people already have (CDC, 1992). Moreover, because chronic
diseases like heart disease and osteoporosis develop over a lifetime, primary
prevention needs to be viewed as a lifelong (decades long) undertaking. It is
not something that is accomplished over a year or a few years. Within this
context, the HOPE study was clearly a secondary prevention trial. It had nothing
to do with primary prevention. Study subjects were selected because they
already had advanced heart disease. Consequently, attributing the findings of
this study to the general (healthy) public is inappropriate.
Is it
possible for something to be an effective primary preventive agent without
being an effective secondary preventive agent? I believe so. Dentists tell us
to floss our teeth to prevent tooth decay and avoid the need for root canal
surgery. If you were to select a group of people with advanced tooth decay,
many who had chronic tooth aches, and divided them into two groups, telling one
to floss regularly and the other to refrain from flossing, what do you think
would happen? Would the flossing group experience significantly fewer tooth
aches, fewer tooth extractions and fewer root canal surgeries in the
short-term? Probably not; the flossing came too late in the day to change the
course of existing disease.
A similar
situation may exist with respect to vitamin E and heart disease. It is very possible
that vitamin E, acting as an antioxidant over the long-term, may help to
prevent atherosclerosis. Epidemiological research certainly supports this
notion. However, vitamin E may be ineffective in preventing the rupture of
existing atherosclerotic plaques (thus triggering a heart attack, stroke, or
cardiovascular death). The HOPE trial and similar clinical studies support this
notion. As such, vitamin E supplementation may be an effective long-term
measure for the primary prevention of heart disease, while being an ineffective
short-term secondary prevention measure or cure (Lewis, 2004). Clearly this
hypothesis deserves attention, and the following study put it to the test.
B. Vitamin E and the Primary
Prevention of Heart Disease
In 2005, the
results of a clinical trial on vitamin E supplementation for primary prevention
of heart disease and cancer were published in the Journal of the American
Medical Association (Lee et al, 2005). This randomized placebo-controlled study
involved almost 40,000 women at least 45 years of age who had no history of
heart disease or cancer. Half of the women were assigned to the vitamin E
treatment (600 IU natural-source vitamin E every other day). Half were assigned
to placebo. Average follow-up was just over 10 years. As such, this trial
differed from the HOPE study in that it was a true primary prevention trial.
Moreover, it lasted a full decade, an improvement over HOPE’s 4.5 year
duration.
Results of
the study indicated that vitamin E had no effect on cancer incidence or cancer
mortality. However, there were notable benefits for cardiovascular health.
Overall, vitamin E use showed a protective trend toward reducing the risk of
total major cardiovascular events among all women in the study. While
individual impacts on heart attacks and stroke were nil, there was a
statistically significant 24% reduction in cardiovascular deaths among women in
the vitamin E group. And importantly, when the data for women at least 65 years
old were examined separately, there was a significant 26% reduction in major
cardiovascular events, which included a 34% reduction in nonfatal heart attacks
and a 49% reduction in cardiovascular death. These are very significant
protective effects, and they are particularly relevant because women tend to
suffer from heart disease in their senior years following menopause (Mosca et
al, 1997). As such, if vitamin E were to have an effect, it would likely be
most pronounced in this age group.
Despite these
findings, the conclusions reported in the abstract of the study were as
follows.
“The data from this large trial indicated
that 600 IU of natural-source vitamin E taken every other day provided no
overall benefit for major cardiovascular events or cancer, did not affect total
mortality, and decreased cardiovascular mortality in healthy women. These data
do not support recommending vitamin E supplementation for cardiovascular
disease or cancer prevention among healthy women.”
This despite
the fact that vitamin E supplements reduced cardiovascular deaths by 24% across
all women and by 49% among women 65 years or older. Why was this benefit
largely ignored? Because cardiovascular death, while measured in the study, was
not a specified clinical parameter – in other words, because the study was not
specifically designed to report on this benefit. So instead the authors
concluded there was “no overall benefit” and that the results of the study
“[did] not support recommending vitamin E supplementation for healthy women.”
These
conclusions appear less than objective, and they beg the question of bias
against nutritional supplements, or primary prevention, or both in the medical
community. Would it not have been more appropriate to conclude that vitamin E
had an apparent primary preventive effect against heart disease in women, and
that the benefits were most significant in senior women…the group at highest
risk for suffering a major cardiovascular event? I will return to this point
later.
C. The Safety of Vitamin E is
Questioned
In January
2005, a research article entitled “Meta-Analysis: High-Dosage Vitamin E
Supplementation May Increase All-Cause Mortality” was published in the Annals
of Internal Medicine, a respected medical journal (Miller et al, 2005). This
study called the safety of vitamin E supplements into question. It was
conducted by scientists at Johns Hopkins Medical Institutions who pooled the
results of 19 clinical trials involving vitamin E supplementation at doses of
16 to 2,000 IU per day. In total, the 19 trials included almost 136,000
subjects. In none of the individual trials was a statistically significant
increase in mortality observed from vitamin E supplementation. But when the 19
trials were examined together, there were weak but apparent trends towards
decreased mortality in subjects taking low doses of vitamin E (< 400 IU/d)
and increased mortality in subjects taking high doses of vitamin E ( 400
IU/d). The overall conclusion of the statistical analysis was that high-dose
vitamin E may increase the risk of all-cause mortality by about 5%, and
therefore, should be avoided. Could the results be real? Yes, it is possible.
At high doses, some essential nutrients can produce imbalances and adverse
effects (Hathcock, 1997a). Nevertheless, three important points argue against
the conclusions of this study. First, the toxicology and safety of vitamin E
have been extensively reviewed, and experts agree that tolerable upper intakes
are on the order of 1000 mg per day (about 1500 IU per day) (Hathcock, 1997b,
Food and Nutrition Board, Hathcock et al, 2005). Second, several large
epidemiological studies that identified and followed groups of people consuming
high doses of vitamin E (>400 IU/d) over the long-term, did not show
increased risk of mortality. In fact they generally showed a reduced risk of dying
relative to those people consuming the least amounts of vitamin E (Stampfer et
al, 1993; Rimm et al 1993; Losonczy et al, 1996; Meyer et al, 1996; Kushi
1999).
Third, while
it is possible that high-dose vitamin E could have adverse effects for certain
groups, the Johns Hopkins study did not provide conclusive evidence of harm.
The study suffered from several important weaknesses. As noted by the authors
themselves, all of the studies included in the meta-analysis were conducted on
subjects who were chronically ill. They included patients with heart disease,
cancer, Alzheimer’s disease, type 2 diabetes, or related disorders. In short,
the subjects were at high risk for dying to begin with. In addition, many of
the studies included in the analysis were small, containing several hundred as
opposed to several thousand subjects. And in fact, the smaller studies were the
ones that typically showed the larger deviations from normal mortality rates.
Given these issues, the authors concluded that “the generalizability of the
findings to healthy adults is uncertain”.
Moreover, a
third and critical weakness of the analysis was largely overlooked. In all, the
authors identified 36 studies involving vitamin E supplementation that fit the
primary criteria for review. Of these, 19 were included in the final
meta-analysis, five were excluded because mortality data was not available or
was insufficiently reported, and 12 studies were excluded because not enough
people died in them. This latter exclusion is suspect. The authors suggest that
mortality data was available, but close to zero in both the vitamin E and
control treatments. I would argue that this is not a sufficient and rational
reason for excluding the studies from the analysis. And given the weak nature
of the trends as reported in the paper, it is highly likely that no effect of
vitamin E on all-cause mortality would have been seen had the 12 additional
studies been included in the meta-analysis. As such, I believe that the results
and conclusions of the study are seriously flawed and biased. I would be less
critical if the title of the paper had been “High-Dosage Vitamin E
Supplementation May Increase All-Cause Mortality in Very Ill Subjects at High
Risk for Dying”; and if the conclusion had been that high dose vitamin E should
be used cautiously by chronically ill people in that high risk group. But these
distinctions were not evident in the paper or the press.
The Need for a Broader Healthcare
Perspective
Our current
approach to healthcare, with its almost singular focus on reactive acute-care
medicine, presents challenges for the study and implementation of long-term
primary preventive healthcare measures, including nutritional supplementation.
As the cases discussed above illustrate, nutritional supplements are often
tested inappropriately, results of studies are interpreted less than
objectively, and valid but non-clinical evidence of benefit is often ignored or
discounted.
Do these
studies constitute bad science? Clearly, some of the methodologies are flawed.
The criteria for exclusion of studies from the Johns Hopkins meta-analysis are
questionable, and they likely biased the results and conclusions of this
research. However, the real challenge is not so much one of poor science as it
is one of inappropriate approach and trial design. The majority of studies on
the health benefits of nutritional supplements have tested supplements as
though they were acute-acting therapeutic agents expected to provide dramatic
health benefits over the short-term in acutely ill people. This is a
fundamentally flawed outlook.
The principal
value of nutritional supplementation lies in primary prevention; that is, in
approaches to keeping healthy people healthy. Importantly, primary prevention
is also a lifelong undertaking. We suffer heart attacks and hip fractures as
seniors, but the roots of heart disease and the beginnings of osteoporosis are
evident in childhood and adolescence. As such, the prevention of these diseases
needs to begin in childhood and progress lifelong. The timeframes of primary
prevention are measured in decades and lifetimes, not in hours, days, months,
or years.
Such long
timeframes are beyond the purview of acute-care medicine, in part because they
pose significant operational challenges for clinical research. How does one
manage a double blind, placebo-controlled clinical trial, the gold standard of
medical science, over a period of decades? Epidemiological studies more easily
embrace long timeframes, and as such are useful in studying preventive measures.
However, they also tend to be less well controlled and less precise. This
troubles many in mainstream medicine who then discount or disregard
epidemiological science altogether. Does this constitute tunnel vision? I
believe it does. Our understanding of the link between a balanced diet and
long-term health is largely based on epidemiology. Our understanding of the
link between smoking and lung cancer is largely based on epidemiology. In
short, good epidemiological research constitutes sound science and should not
be discounted or ignored (Kushi, 1999; Potischman and Weed, 1999). It was a
mistake in 1964 when the American Medical Association refused to endorse the
Surgeon General’s Report on Smoking (the AMA was the last public health
organization to do so), claiming that the research was inconclusive (Weiner,
1996). And it is a mistake today to overlook epidemiology in assessing the role
of nutritional supplements in preventive healthcare. In short, advances in
primary prevention will require healthcare scientists to review and give
serious consideration to a broad body of scientific evidence that extends well
beyond the clinical trial paradigm.
It will also
require a more open-minded and objective interpretation of results. The finding
that vitamin E supplementation, over a 10 years period, reduced cardiovascular
deaths by 24% in women over 45 years of age, and by 49% in women over 65 years
of age (Lee et al, 2005) may have been disappointing to those steeped in acute
care medicine (although I don’t understand why). But these are significant and
positive findings within the context of primary prevention. In short, vitamin E
worked. Why then did the authors conclude that it “provided no overall benefit
for major cardiovascular events” and refrain from recommending vitamin E
supplementation for the primary prevention of heart disease? And why did the
popular press lead their coverage of this study with headlines stating “Vitamin
E Gets and ‘F’”? Simply put, the findings did not fit the paradigm.
Poor
reporting and bias in the press is easy to understand. Most journalists are not
trained scientists, statisticians, or healthcare professionals. As such, they
are not qualified to interpret medical studies objectively and competently.
Moreover, Job One at major news organizations involves selling more newspapers
and capturing more viewers, and they accomplish this by crafting controversial
headlines and scary sound bites. If you want the masses to listen, frighten
them. Unfortunately, the delivery of objective and complete information appears
to be a distant Job Two.
This is an
unfortunate situation, in that many Americans rely on the popular press for
their health information. As such, the sensational and controversial coverage
given to nutrition news has generated confusion, doubt, and skepticism in the
public’s mind, turning many against the diet and health message (Patterson et
al, 2001).
Why would
medical professionals have a negative bias against nutritional supplements?
Several reasons come to mind. Most doctors receive no more than a few hours of
nutritional training during their medical education. They know little about
nutrition and the important role it plays in human health. Second, many express
concerns that their patients might use supplements as an excuse to eat poorly.
This concern has proved to be unfounded. Surveys show that supplement users
tend to be health-conscious and to follow generally healthy habits. Third, many
doctors have a low opinion of the nutritional supplement industry - and
rightfully so. Too many supplement companies sell substandard products that
fail to meet pharmaceutical standards for potency, purity, and efficacy. Too
many companies fail to pay sufficient attention to safety. And too many
companies make false and outrageous health claims for their products. Clearly
this industry needs an overhaul to win the respect and confidence of doctors
and the general public. But just as clearly, there are very reputable
supplement companies in business today; companies that have adopted pharmaceutical
standards for product quality, safety and efficacy; companies that deserve the
public’s trust.
These issues
aside, I believe that the most significant barrier to the open consideration of
supplement use in mainstream healthcare is the closed mind. Primary prevention,
the focus of keeping healthy people healthy, lies outside the acute-care
paradigm, and so it is ignored. Some in the mainstream pay lip service to
prevention, but few base their practices or research careers on it. And sadly,
because primary prevention is “alien”, it is often derided as “ineffective”,
“too slow”, “unreliable”, “clinically unproven”, and “only partially
effective”.
Unfortunately,
these attitudes carry over to nutritional supplements. As tools of primary
prevention, nutritional supplements also lie outside the acute care paradigm.
When they are evaluated within that paradigm for short-term treatment /
curative benefits, one or two nutrients at a time, on chronically ill people,
they often fail. These failures, in turn, are judged as evidence that
supplements have no benefit whatsoever.
Clearly it’s
time to challenge these notions and views. Change may begin at the grass roots
level, as rising healthcare costs threaten to close the doors of access to good
medical care. Today, too many Americans literally can’t afford to get sick. Our
alternative is primary prevention. We can choose to take charge of our health
by adopting prudent lifestyle strategies and habits for staying healthy
long-term. Nutritional supplementation can play an important role in this
endeavor. The science, when approached broadly with an open mind, is convincing
on this point. As components of healthy living, nutritional supplements can
help people add years of health to their lives.
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