A new study published in JAMA indicates 52 percent of American adults took supplements in 2011-2012, a rate that has remained steady since 1999, despite mixed evidence supplements benefit health — and some evidence they may be harmful.
In a corresponding editorial in JAMA, Pieter Cohen, MD, details the regulatory changes in the late 1980s that popularized vitamins and supplements. He writes that the Dietary Supplement Health and Education Act of 1994, which deems supplements safe until the Food and Drug Administration finds evidence of harm, helped lay the foundation for a $32 billion industry in 2012.
The period of the study, 1999 to 2012, "was an era of intense investigation into the health effects of supplements," according to Dr. Cohen. NIH poured $250 million to $300 million annually into dietary supplement research during this time, and most of this research did not demonstrate much benefit, according to Dr. Cohen. In fact, some supplements were found to be harmful — such as those that contained ephedra and were linked to heart attacks, seizures and strokes. However, Dr. Cohen wrote not all supplements are harmful or ineffective. For example, certain multivitamins can help delay age-related macular degeneration. "But even supplements that are useful in treating certain conditions are frequently overused among the general population to 'improve' or 'maintain' health, and only about one-quarter of consumers use supplements based on the advice of their clinicians," Dr. Cohen wrote.
Despite lack of evidence showing supplments work, the recent JAMA study, based on in-home interviews of nearly 40,000 U.S. adults over seven continuous two-year cycles, indicates a majority of Americans still use them.
A closer look at the data reveals smaller trends in supplement use as certain vitamins, minerals and botanicals came in vogue and faded away again. Though general use has remained steady, the research indicates the supplements of choice may have shifted over the study period. For example, the use of multivitamins/multiminerals decreased from 37 percent in 1999-2000 to 31 percent in 2011-2012. Meanwhile, the use of vitamin D supplements jumped from 5.1 percent to 19 percent, and the use of fish oil supplements increased from 1.3 percent to 12 percent.
Dr. Cohen suggests consumers may be continuing to use supplements because they do not know they are ineffective, and physicians have the responsibility to consult patients on the use of supplements.
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