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Summer 2004 Vol. 4 No. 2

Table of Contents

©Getty Images/StoneSupplements and Safety

A New Process to Enhance the Safety of Dietary Supplements

Gingko biloba to enhance memory. Zinc to boost the immune system. Vitamins to make up for not eating our vegetables. Over the past decade, the dietary supplement industry has ballooned to huge proportions in the United States, with over 29,000 products on the market ringing up more than $16 billion in annual sales. About 1,000 new products are introduced each year.

Consumers generally assume that all dietary supplements are safe, surveys show. But are they? The U.S. Food and Drug Administration's removal of the herbal supplement ephedra -- which was linked to several deaths -- from the marketplace last December highlighted concerns about the current law that governs how supplements are regulated. Does it give the agency sufficient means to deal with problem products?

Although consumers frequently use dietary supplements to enhance their health, these products by law cannot be considered therapeutic. Unlike prescription drugs, which must be proved safe before being allowed on the market, dietary supplements are assumed to be safe for human consumption from the start. Regulated the same way foods are, supplements can be removed from the market only if FDA can determine that they are unsafe.

FDA faces a number of hurdles when it comes to determining the safety of these products, not the least of which is the lack of data on effects in humans. This is usually the case, because manufacturers are not required to conduct clinical studies that establish safety of supplement ingredients and provide the results to FDA. However, it is possible to use other types of data to determine when regulatory action is needed, says a recent report from the Institute of Medicine.

The report provides FDA with a science-based process to gather and weigh the different kinds of available evidence that can shed light on an ingredient's potential to cause harm to consumers. Data from studies on animals, information about the adverse health effects of similar or related substances, and evidence of toxic effects on cell cultures all can be used to assess an ingredient's safety for people.

One of the chief concerns raised by the ephedra case is whether the agency has the authority to take action on a supplement before serious illnesses or deaths occur. The law says that the agency must show that a supplement ingredient poses "an unreasonable or significant risk." The report underscores the agency's ability to act even without direct evidence of injury to consumers. The other sources of data described in the report can be used to determine if an ingredient could cause harm.

While the proposed new process is designed to help FDA carry out safety evaluations even when data are limited, it would be easier for the agency to do its job if it had greater access to data. The report calls on Congress to require supplement manufacturers and distributors to disclose in a timely fashion to FDA any adverse events related to consumption of their products. Currently, supplement makers are not required to collect or report health problems they discover once their products are on the market, which significantly hampers the agency's ability to actively monitor supplement safety. It has been estimated that FDA receives information on less than half of 1 percent of all adverse events associated with supplements. To further boost reporting, supplement labels should include a toll-free number for consumers and health professionals to call if health problems or concerns related to the product occur, as well include the names and locations of both the distributor and the manufacturer so that any problems can be traced more easily to their source.

Using the framework offered in the report, FDA can meet its responsibility to protect the health of the public within the parameters of the current law on supplement regulation. But changes in the law would allow the agency to do the job more readily, while not subjecting dietary supplement manufacturers to lengthier, more burdensome requirements.   -- Christine Stencel

Dietary Supplements: A Framework for Evaluating Safety. Committee on the Framework for Evaluating the Safety of Dietary Supplements; Food and Nutrition Board, Institute of Medicine, and Board on Life Sciences, Division on Earth and Life Studies (2004, 370 pp.; ISBN 0-309-09110-1; available from the National Academies Press, tel. 1-800-624-6242; $59.95 plus $4.50 shipping for single copies).

The committee was chaired by Barbara O. Schneeman, professor of nutrition, food science, and internal medicine, University of California, Davis. The study was funded by the U.S. Food and Drug Administration.

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Copyright 2005 by the National Academy of Sciences