Baltimore Sun
06-02-06
The great vitamin debate
Do supplements help? According to a federal panel, the answer is: 'maybe'
By Dennis O'Brien
Sun reporter
Confused about taking vitamins? So is the government.
A staple on U.S. store shelves since the 1930s, vitamins have been the focus of
hundreds of studies. Vitamins have also mushroomed into a $7 billion business,
with more than half of all Americans either taking a vitamin or a supplement in
one form or another.
Lacking a consensus on whether vitamins actually work, a federal panel this
spring completed its search for evidence that they help people stay healthy by
preventing cancer and other diseases.
The group commissioned a review of every vitamin study conducted during the
past 40 years, met with the scientists who conducted that review and held a
three-day conference last month to question leading experts.
The bottom line? Vitamins may help. Or not.
"The present evidence is insufficient to recommend either for or against the use"
of vitamins, says the 18-page report, released May 17 by a National Institutes of
Health panel.
Conclusions are elusive because there have been so few randomized, controlled
trials of vitamins' effectiveness. These studies, which compare results from a
group that ingests a product with a group that receives a placebo, are the gold
standard for medical research. They are also expensive.
"The whole area of nutrition research over the years has been underfunded,"
said Diane Birt, a member of the NIH panel and an expert on diet and cancer
prevention at Iowa State University.
The federal panel recommended more thorough studies and a requirement that
supplement makers report toxic reactions to the Food and Drug Administration,
as pharmaceutical firms must do. Currently, supplement makers do not have to
report these problems to the government.
The panel, appointed by the NIH Office of Medical Applications of Research and
the Office of Dietary Supplements, issued specific recommendations about
vitamins for post menopausal women, women of childbearing age, smokers and
those at risk of early-stage macular degeneration, a disease that causes
blindness.
But critics said the panel set the bar too high by limiting its conclusions to
findings derived from human clinical trials. "The panel's rules and design were so
limited, it seems like the conclusions were preordained," said Brian Sanderoff, a
pharmacist with an Owings Mills outlet that specializes in the sale of vitamins and
nutritional supplements.
The panel seemed to ignore overwhelming evidence that popular multivitamins
can help millions of people who don't eat properly, said Jeffrey Blumberg,
nutrition professor at Tufts University.
Only 3 percent of the U.S. population follows the government's 2005 Dietary
Guidelines, and the guidelines advisory committee reported last year that many
people aren't getting enough vitamin E, calcium, magnesium, potassium and
fiber, Blumberg said.
"I'm not saying [multivitamins] are a substitute for a healthy diet, but you're not
going to have a shortfall of any vitamin if you take a multivitamin," said Blumberg,
who was not on the panel but attended the conference.
Blumberg said the NIH panel should have looked at smaller studies that link
vitamin use to reduced cancer risks, improved bone density among women and
other health benefits.
"There's lots and lots of smaller studies, observational studies, that suggest
there are benefits to multivitamins," Blumberg said.
But panel members say these so-called "observational" studies are less reliable
because they are based on recording the health of people who take vitamins in
the first place - and tend to take better care of themselves than the average
American.
That makes it difficult to know why someone experiences a specific health
benefit, such as lower blood pressure or reduced bone loss, Birt said.
"The question becomes, 'Is it the exercise, is it the person's diet or is it the
multivitamin they're taking?' We just don't know," Birt said.
The NIH panel commissioned researchers at the Johns Hopkins Bloomberg
School of Public Health to review every scientific study conducted from 1966 to
February of this year, looking for any clinical trials that examined the effects of
vitamin use on overall population groups.
There were only two - and neither is particularly useful to researchers interested
in U.S. populations, said Han-Yao Huan, the nutrition expert at Hopkins who led
the research.
In one, researchers examined the effects of multivitamin use by rural Chinese
peasants. The other focused on diets among the French from 1996 to 2004.
The Chinese study was 20 years old and focused on a nutritionally deprived
population, Huan said. And, although the French have the same problems with
fatty foods and high cholesterol levels as Americans, they have different diets
and generally are at lower risk for heart disease. That's a phenomenon
researchers often refer to as the "French Paradox," she said.
The lack of clinical trials involving vitamins is not surprising because studies are
costly and take a long time, Huan said.
A drug company has a financial incentive to finance a clinical trial because it's a
requirement to win FDA approval for a new drug. But experts see little incentive
to fund clinical trials for the vitamins that the National Academy of Sciences
already considers important enough to include in the recommended dietary
allowances on food labels.
At stake is the reputation of a huge and growing vitamin supplement industry
whose roots can be traced to 1924, when iodine was added to salt to prevent
goiter. Next came vitamin D, which was added to milk to prevent rickets in 1933.
Vitamins have since grown into a huge industry, accounting for almost a third of
the $23 billion Americans spend on nutritional supplements each year, according
to the Nutrition Business Journal. Nutritional supplements also include herbs,
botanicals, sports drinks and liquid meal supplements.
Sanderoff's Owings Mills business, called Your Prescription for Health, has been
growing steadily during the past 15 years, he says. About three months ago, he
opened a 10,000-square-foot outlet on Dolfield Road in Owings Mills that
includes a yoga center, nutritional counseling and a sales center that offers
vitamins and supplements from more than 300 companies.
"There's no question that interest is picking up," he said.