NEW YORK (Reuters Health) — There
is not enough evidence to recommend that people take multivitamins
or single or paired nutrients to prevent cancer or heart disease,
according to a government-backed panel.
But there is enough evidence to recommend that
people do not take beta-carotene or vitamin E to prevent those
conditions, the U.S. Preventive Services Task Force (USPSTF) said.
The final recommendations, published in the Annals of Internal
Medicine, largely mirror draft guidelines that were released by the
USPSTF in November (see Reuters Health story of November 11, 2013
here: http://reut.rs/1e1ilDe.) They do not apply to people with
known vitamin deficiencies or chronic illnesses.
"Because so much money is spent and so many people think they're
doing themselves good by taking multivitamins, we really do need
research to find out if that is the case," Dr. Virginia Moyer, who
chairs the USPSTF, told Reuters Health.
Moyer is also the vice president for maintenance of certification
and quality at the American Board of Pediatrics in Chapel Hill,
North Carolina.
While generally calling for more research on vitamins, the USPSTF
concluded there is enough evidence that beta-carotene increases the
risk of lung cancer among those who are already more likely to
develop it, such as smokers.
After reviewing six trials, researchers who compiled a summary of
available evidence for the panel found there were few or no harms
linked to taking vitamin E, but it also did not reduce the risk of
heart disease or cancer.
Duffy MacKay agreed that the new recommendations are a call for
additional research — especially research that takes into account
the nuances of nutrition.
He is senior vice president for scientific and regulatory affairs at
the Council for Responsible Nutrition, a trade association in
Washington, D.C., that represents dietary supplement manufacturers
and ingredient suppliers.
For example, MacKay pointed out that it's difficult to compare the
effectiveness of multivitamins or nutrients in trials similar to
those that evaluate traditional drugs, because all people usually
get some of the vitamins or nutrients through their diet.
But he said his organization has compiled research that shows
there are meaningful nutrient gaps in the general population.
"A significant portion of Americans are falling short in essential
nutrients," MacKay told Reuters Health. "Most Americans will benefit
from a multivitamin as an insurance policy."
He said it's important for people to talk with their health care
practitioner about the products that are right for them.
Moyer said the USPSTF reevaluates recommendations about every five
years, but there are some exceptions if a topic is prioritized.
In general, she said people should be getting the vitamins and
nutrients they need from their diet.
"It's probably not the individual vitamins or minerals or anything
else," she said. "It's what you get from the whole of a balanced
diet."
