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Vitamins: More May Be Too Many
By GINA KOLATA
The New York Times
 
A growing number of medical experts are concerned that Americans
are overdoing their vitamin consumption. As many as 70 percent of
the population is taking supplements, mostly vitamins, convinced
that the pills will make them healthier.

But researchers say that vitamin supplements cannot correct for a
poor diet, that multivitamins have not been shown to prevent any
disease and that it is easy to reach high enough doses of certain
vitamins and minerals to actually increase the risk of disease.

No longer, the experts say, are they concerned about vitamin
deficits. Those are almost unheard of today, even with the
population eating less than ideal diets and skimping on fruits
and vegetables. Instead, the concern is with the dangers of
vitamin excess.

"There has been a transition from focusing on minimum needs to
the reality that today our problem is excess — excess calories
and, yes, excesses of vitamins and minerals as well," said Dr.
Benjamin Caballero, a member of the Food and Nutrition Board at
the National Academy of Sciences and the director of the Center
for Human Nutrition at Johns Hopkins University. 

Dr. Caballero said that for some supplements, including vitamin
A, the difference between the recommended dose and a dose that
could lead to bad outcomes like osteoporosis was not large.
Popular multivitamins, he added, often contain what could be
risky doses. 

"Certainly," he said, "by consuming supplements, people can reach
that level." 

Doctors who once told patients that multivitamins were, at worst,
a waste of money now say they are questioning that idea. 

"All of a sudden, scientists are rearing back and saying, `Wait a
minute, do we really know that we need this and do we really know
that we need that?' " said Dr. Ruth Kava, nutrition director at
the American Council on Science and Health, a consumer foundation
in Manhattan that is in part financed by industry. 

With vitamin A in particular, it is easy to step over the edge
into a danger zone, said Dr. Joan McGowan, chief of the
musculoskeletal diseases branch at the National Institute of
Arthritis and Musculoskeletal and Skin Diseases. 

"You can be eating Total cereal, drinking fortified milk, taking
a multivitamin," Dr. McGowan said. "You can get into a situation
where you're getting more than you need. Until recently, there
was little concern about vitamin A and bone health." 

Now, she added, "we may have to rethink the issues."

Similar questions are being raised about other vitamins and
minerals, notably iron and vitamins E and C.

Researchers say the questions involve multivitamins taken by
healthy people, not specific vitamins or minerals taken by groups
with specific needs. Some elderly people, for example, may be
deficient in vitamin B12 because they lose their ability to
absorb it from foods. People who spend little time outdoors may
require vitamin D, which the skin makes when it is exposed to
sunlight. Even when older people are in the sun, aging skin loses
much of its ability to synthesize the vitamin. 

Pregnant women who do not receive enough folic acid, a vitamin in
fruits and vegetables that is added to enriched flour, are at
increased risk of having babies with neural tube defects. Because
the vitamin is needed at the very start of pregnancy, some
advocate folic acid supplements for all who might become
pregnant, just to be sure they are protected.

For most people, however, the issue is not deficits. Instead,
nutrition researchers ask: Do people eating relatively healthy
diets with fresh fruits and vegetables and not too many calories
or fats benefit from multivitamins or other supplements? Do those
whose diets are abysmal, heavy on fast foods and lacking in
fruits and vegetables, make up for some deficits if they take
multivitamin pills?

Dr. Annette Dickinson, president of the Council for Responsible
Nutrition, a group that represents the supplement industry, says
70 percent of Americans sometimes take supplements — usually
multivitamins or individual vitamins and minerals — and 40
percent take them regularly.

"Our position," she said, "is that most people, literally most
people, would benefit from taking a multivitamin every day. It's
insuring adequate and even generous intake of all the nutrients."

The most popular individual supplements are vitamins C and E,
said Dr. Robert M. Russell, the director the Human Nutrition
Research Center of Agriculture Department at Tufts University,
who is head of the Food and Nutrition Board. Scientists once
thought those vitamins could help prevent ailments like cancer
and heart disease, but rigorous studies found no such effects.

Vitamin E supplements can increase the risk of heart attacks and
strokes, and studies of vitamin C supplements consistently failed
to show that it had any beneficial effects. 

"The two vitamins that are the most not needed are the ones most
often taken," Dr. Russell said. 

Excess vitamin C is excreted in the urine, but excesses of some
other vitamins are stored in fat, where they can build up. Of
particular concern, researchers say, is vitamin A. It is found in
liver, and small amounts are added to milk. But for most people
who are reaching worrisome levels, the main source is
supplements, multivitamins, nutrition bars, health drinks and
cereals. 

Several recent large studies indicate that people with high
levels of vitamin A in their blood have a greater risk for
osteoporosis. People can easily reach a potentially dangerous
level, about five times the recommended dose, by taking vitamins
and supplements, nutrition researchers say. Some popular
multivitamins run 1,500 micrograms a pill, twice the recommended
daily amount and a level that, in one recent study, doubled the
risk of bone fractures. Some supplements provide as much as 4,500
micrograms a day, well above the level that the National Academy
of Sciences calls an upper limit for safety.

"If you have a good source of vitamin A in your food and you take
a supplement with another 100 percent, you can easily reach a
level that can accumulate" to one associated with increased risk
of osteoporosis, Dr. Caballero said.

Dr. Dickinson said that multivitamin manufacturers were
decreasing the vitamin A in their products, but that it might
take a year for the reformulated products to appear. 

Others warn about overdosing on other vitamins and minerals.

Dr. Richard J. Wood, director of the mineral bioavailability
laboratory at Tufts, worries about iron overload, which can
increase the risk of heart disease. In a large federal research
effort, the Framingham study, Dr. Wood found that 12 percent of
the elderly participants had worrisome levels. "Hardly anyone had
iron deficiency anemia," he said. "But 16 percent were taking
iron-containing supplements." 

While readily noting that the proof of a benefit is not in, some
researchers said they took multivitamins. They agree with Dr.
Joann E. Manson, chief of preventive medicine at Brigham and
Women's Hospital in Boston, who takes a multivitamin and
recommends it to patients whose diets seem imbalanced. 

"I think it's a good form of insurance," Dr. Manson said. "I
don't think there's a significant downside. We don't have the
evidence yet that it is beneficial."

Dr. Robert H. Fletcher, a professor of ambulatory medicine at
Harvard Medical School, also takes multivitamins. For him, the
deciding factor was whether he ingested enough folic acid.
Studies have suggested that high levels of folic acid can protect
against heart disease by lowering levels of another substance,
homocysteine. High levels of homocysteine are associated with
increased risks of heart disease, but there is no study showing
definitively that reducing homocysteine levels protects against
heart disease.

So far, the folic acid studies are suggestive, not definitive.
But Dr. Fletcher said, "If I were a betting man, I'd bet on it." 

But a European study, reported recently at a meeting of the
American College of Cardiology, found that folic acid supplements
actually made matters worse for heart disease patients. The
study, the Folate After Coronary Intervention Trial, involved 626
patients who were having stents inserted into blocked arteries to
keep them open. Half were randomly assigned to take folic acid,
and the rest took a placebo. Six months later, the arteries of
those taking folic acid were significantly narrower than the
arteries of those taking a placebo, exactly the opposite of what
the investigators had expected.

A previous study, however, had found that folate helped such
patients. Dr. Eric Topol, an interventional cardiologist at the
Cleveland Clinic, said he thought the truth was that it was
neither helpful nor harmful for most people. "Over all, the
likely explanation is that there is a neutral effect, and these
relatively small trials found opposite findings due to the play
of chance," he said.

Dr. Topol said B vitamins, like folic acid, "can't be
recommended" at this point, except for people with extremely high
levels of homocysteine, and even then their value has not been
rigorously demonstrated. 

Karen Miller-Kovach, chief scientist for Weight Watchers
International, has a compromise. She takes a child's
multivitamin, with its much lower levels of vitamins and
minerals.

"It is virtually impossible to find an adult multivitamin and
mineral supplement that is only 100 percent of the R.D.A.," Ms.
Miller-Kovach said. "All are 150 percent or so. I worry about
getting too much and I worry about imbalances. They put in more
of the things that are inexpensive, like B vitamins and things
with consumer appeal like vitamin C. The formulas are based on
market forces, not nutritional needs."

Others decided against taking the pills. 

Dr. Kava, of the American Council on Science and Health, said she
abstained. "People ask me what vitamins I take," she said. "I say
I don't take any. They look at me askance. They can't believe I'm
a nutritionist." 

Dr. Caballero also does not take vitamins. "There is no disease I
know of that is prevented by multivitamins," he said.

In fact, Dr. Caballero said, typical pills, which contain a
variety of minerals as well as vitamins, have ingredients that
actually cancel out one another. "Minerals antagonize each other
for absorption," he said. "Zinc competes with iron which competes
with calcium." 

Dr. Caballero also notes that large, rigorous studies that were
supposed to show that individual vitamins prevented disease ended
up showing the opposite. Those who took the vitamins actually had
more of the disease it was meant to prevent.

Two large randomized trials of vitamin A and beta carotene that
researchers hoped would show a protective value against cancer
found no benefit, and one found that participants who took the
supplements had more cancer.

A large study of vitamin E and heart disease found that it did
not prevent heart attacks and that people taking it had more
strokes. 

Another study, of women with heart disease, found that
antioxidant vitamins might actually increase the rate of
atherosclerosis.

Dr. Caballero said people were deluding themselves if they
thought multivitamins could make up for poor diets.

"If you eat junk food every day, vitamins are the least of your
problems," he said. "You cannot replace a healthy diet. We don't
know what ingredient in a healthy diet is responsible for which
condition. We do know that people who consume five servings or
more of fruits and vegetables have less disease. But we don't
know which ingredient. We tried beta carotene, vitamin E and
antioxidants, and they didn't work.

"People are looking for the magic bullet. It does not exist."




.:. Craig