By Kim Painter, Special for USA TODAY
Healthy post-menopausal women should not take low-dose vitamin D
and calcium supplements in hopes of protecting their bones, a panel of
government advisers says in a new recommendation.
The
supplements don't work for that purpose, at least when taken at the
relatively low daily doses that have been most thoroughly studied, says
the U.S. Preventive Services Task Force. The advice, published Monday in
the Annals of Internal Medicine, covers daily doses up to 400 international units (IU) of vitamin D and up to 1,000 milligrams of calcium.
The recommendation is an official vote of no confidence in a very
popular supplement combination. Though it closely tracks a draft
released months ago and is based on widely reported studies, it may come
as a shock to many consumers. More than half of U.S. women over age 60
now take the supplements at various doses, according to the task force.
The recommendation also is likely to spawn confusion because it
doesn't cover younger women, men or higher doses. The task force says it
has inadequate evidence on all those issues. It also continues to study
whether vitamin D has any role in preventing cancer. And it is standing
by a previous recommendation that people who are over age 65 and at
high risk for falls - a big group of people - should take vitamin D
supplements.
"We know that vitamin D and calcium are
essential to bone health," says task force member Jessica Herzstein, a
public-health specialist who is global medical director at Air Products
in Allentown, Pa. But studies including the Women's Health Initiative
show that low-dose supplements don't prevent fractures in healthy older
women, the task force says. Research also suggests that about one in
273 women taking the supplements will develop kidney stones. It's a
small risk but worth considering, Herzstein says.
The best
advice right now is for women to talk to their doctors about their risks
for fragile bones and fractures and all the ways they can prevent them,
including diets high in calcium and vitamin D, exercise and prudent sun
exposure, which helps the body produce vitamin D, Herzstein says. Some
will decide to take supplements anyway, and that's OK, she says. "We're
just saying think about it."
But some women who talk with
their doctors will find waning enthusiasm for the supplements, says
Clifford Rosen, a senior scientist at Maine Medical Center Research
Institute and former president of the American Society for Bone and
Mineral Research. He says there's a growing consensus that "most people
are doing very well in the United States in terms of their vitamin and
mineral intake and they don't need supplements." He says there's also
growing concern about potential risks.
While daily doses of
vitamin D up to 4,000 IU appear safe, he says, recent studies suggesting
links between high doses of calcium and heart attack are worrisome. The
task force says that link was not found in the studies it reviewed.
Rosen says he still recommends calcium supplements for patients with
osteoporosis, whose bones are already fragile, but he tells them that
"one pill a day (usually 500 milligrams) is plenty."
Rosen was
a member of another advisory panel that developed calcium and vitamin D
recommendations for the Institute of Medicine in 2010. That panel
concluded that adults need 600-800 IUs of vitamin D and 1,000 to 1,200
milligrams of calcium each day, depending on their age. But it also said
most people were getting adequate amounts without resorting to
supplements. Some other experts have said the panel relied on blood
levels of vitamin D that were too low, and controversy continues about
what constitutes vitamin D deficiency and who should be tested and
treated for it.
The lack of a single, simple recommendation on
vitamin D and calcium is unfortunate for consumers, says Marion Nestle,
a professor of nutrition at New York University and co-author of an
editorial accompanying the task force report. But, she says, the
recommendations are based on what little good science is available.
Nestle says her advice to women is to protect their bones with plenty
of exercise and calcium from food, such as dairy products, and vitamin D
from "15 minutes a day in the sun." That's something even many
dermatologists say is safe, despite the link between sun exposure and
skin cancer, she notes.
But many women who rely on the
supplements may be scared off by a recommendation based on "a very
narrow view of the evidence," says Taylor Wallace, senior director of
science and regulatory affairs for the Council for Responsible
Nutrition, a trade group representing supplement makers.
"I have a
91-year-old grandmother who takes calcium supplements," he says. "It
really scares me that she would see something that says 'stop taking
your calcium, stop taking your vitamin D,' when she doesn't go outside
and she doesn't eat a lot of dairy."
Any evidence of harm from the supplements "is very weak," he says.