Multivitamins: Should you buy this insurance?
The daily multivitamin pill is no substitute for a good diet. But
none of us is perfect when it comes to healthful eating. We may know
all about the virtues of leafy green vegetables and whole grains, but
convenience and cravings lead us astray. The multivitamin is partial
protection from our lapses.
It’s also an easy way to add surplus vitamins and minerals to
our diets. Historically, nutrition focused on vitamin deficiencies that
cause disease. But with fortification — the systemic addition of
nutrients, chiefly vitamins, to the food supply — and no shortage
of food, the focus changed to whether vitamins and minerals in amounts
larger than we need might protect us against conditions like heart disease
Studies go against vitamins
Some people scarf down megadoses, an approach most experts disagree
with. The daily multivitamin is the cautious wager that some extra vitamins
and minerals will pay off in better health even if deficiencies aren’t
Lately, though, it’s been looking like they might not, as high-profile
studies have come to negative conclusions.
It’s well established that a trio of B vitamins — B6, B12,
and folate — lowers homocysteine, an amino acid that’s a
risk factor for heart attack, stroke, and dementia.
But results from a large randomized controlled trial published in the New
England Journal of Medicine (NEJM) earlier this year showed that
while the B vitamins lowered homocysteine levels, that didn’t
result in fewer heart attacks or other major cardiovascular events.
A second disappointing study was published in NEJM. Despite
their homocysteine-lowering prowess, B vitamins were no better than
placebo at protecting people from cognitive decline.
Vitamin E hasn’t been faring too well, either. In 2005 Johns Hopkins
researchers found that large daily doses (400 IU and up) may increase mortality
NIH shrugs its shoulders
The National Institutes of Health (NIH) convened a meeting on multivitamin
and mineral supplements in May 2006. Experts listen to presentations
by other experts for a couple of days, then issue a “state of the
In this case, the statement was extremely cautious. Present evidence
is “insufficient to recommend either for or against the use of
multivitamin/multimineral supplements by the American public to prevent
chronic disease,” was the inconclusive conclusion.
Yes to a multivitamin
Dr. Walter Willett, chair of the Harvard School of Public Health’s
nutrition department, has suggested that taking a multivitamin daily
is a form of nutritional insurance. He still says it’s a good policy,
despite the spate of negative study results.
Those results have come from randomized controlled trials, which are
usually regarded as the gold standard. But there are problems with clinical
trials, too. They’re often fairly short, so a nutrient’s
long-term consequences may be missed.
There are also often questions about how applicable the results of clinical
trials are because of the use of high risk individuals versus healthier
folks. Multivitamins are already part of some official recommendations.
The federal government’s 2005 Dietary Guidelines suggest that people
older than 50 take them as a way to ensure adequate vitamin B12 intake.
And the Centers for Disease Control and Prevention advises all women
of child-bearing age to take folic acid — and a multivitamin is
also a good way to do that.
If you take a multivitamin, be sure to buy a major brand-name or store-brand
product. When Consumers Union tested cut-rate products, it found that
almost half didn’t contain the listed amount of at least one nutrient.
September 2006 Update
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