Jury out on vitamins' use against heart disease, cancer

NEW YORK Mon Feb 24, 2014 5:00pm EST

NEW YORK Feb 24 (Reuters Health) - There is not enough scientific evidence to recommend that people take multivitamins or other nutritional supplements to prevent cancer or heart disease, according to a U.S. government-backed health panel.

The final recommendations, published on Monday in the Annals of Internal Medicine, largely mirror draft guidelines that were released by the U.S. Preventive Services Task Force (USPSTF) in November (See Reuters Health story here: 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.

The new recommendations represent a call for additional research - especially research that takes into account the nuances of nutrition, said Duffy MacKay, senior vice president for scientific and regulatory affairs at the Council for Responsible Nutrition. The Washington-based trade association represents dietary supplement manufacturers and ingredient suppliers.

For example, MacKay said, it is 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.

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."

Moyer said the USPSTF re-evaluates 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."

SOURCE: bit.ly/SQRXAa Annals of Internal Medicine, online February 24, 2014. (Reporting by Andrew M. Seaman; Editing by Genevra Pittman, Michele Gershberg and Jonathan Oatis)