Multivitamins offer almost no benefit in preventing chronic disease "and they should be avoided," experts said Monday in releasing the results of two new clinical trials.
The rigorously conducted studies, published in the Annals of Internal Medicine, showed multivitamins had no effect on cognitive function or cardiovascular health. They are the latest in a series of reports—including a review last month of 26 vitamin studies—indicating that supplements have little health benefits in generally well-nourished, Western populations.
"The message is simple: Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided," four physicians and public health experts wrote in an editorial accompanying the studies.
The editorial added that beta-carotene, vitamin E and possibly high doses of vitamin A increased the risk of death in some other trials.
The global vitamin industry is huge, with sales last year of $23.4 billion, up 3% from 2011, according to Euromonitor International. Sales of multivitamins specifically rose 2.5% last year, to $14.2 billion. About 40% of Americans reported taking multivitamins or minerals between 2003 and 2006, the most recent data available, according to the Centers for Disease Control and Prevention.
Vitamin-industry groups criticized the editorial, and pointed to a study last year of 15,000 men, which indicated that daily use of a multivitamin modestly reduced the risk of cancer. Some experts consider the results an outlier.
"It's no secret that many consumers in this country don't get the recommended nutrients from their diet alone, and multivitamin and mineral supplements are an affordable alternative," said John Shaw, executive director of the Natural Products Association, a trade group.
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