CHAPEL HILL - In 1996, U.S. consumers spent more than $6.5 billion on dietary supplements - ingredients extracted from foods, herbs and plants that are ingested for their possible health benefits.
By last year, the market had almost doubled to $12 billion and is projected to increase to more than $14 billion in the year 2000. Unlike drugs, the compounds are mostly unregulated.
With so much interest in supplements and so many Americans consuming them, the federal government needs to protect the public by creating a special supplement category known as "nutraceuticals" and requiring that they be proven safe before they're sold.
That's the view of Dr. Steven H. Zeisel, professor and chairman of nutrition at the University of North Carolina at Chapel Hill schools of public health and medicine. Zeisel, who says the idea that dietary supplements are natural and therefore must be safe is false, made his remarks in the Sept. 17 issue of the journal Science.
"Increased review and regulation of dietary supplements will decrease (public access) to some beneficial products," the scientist said. "For supplements administered at doses that can be found in foods, adoption of Good Manufacturing Practices (rules proposed by the U.S. Food and Drug Administration for manufacturers) should not significantly alter availability."
For nutraceuticals that expose humans to ingredients at doses they would normally not be exposed to, demonstration of safety could mean it would take years rather than weeks to introduce new products, and some products might never be introduced, Zeisel said.
"This seems a reasonable cost to protect the public health," he said.
Hazards of not testing supplements for safety are real, Zeisel said. The Dietary Supplement Health and Education Act (DSHEA), passed by Congress in 1994, ensures people can buy the products quickly, but also makes it likely that some of those sold will harm people.
"To date, the FDA has asked for the voluntary recall of a product containing the herbal ingredient plantain contaminated with Digitalis lanata after an individual consuming the product suffered a complete heart block," he wrote. "The FDA proposed a regulation to limit the amount of ephedrine alkaloids in dietary supplements (ephedra, Ma Huang) after serious side effects, including death, were observed."
Also recently, the agency asked for voluntary recall of supplements containing a form of butyrolactone because it appeared responsible for serious side effects, including coma and death.
"I propose to define nutraceuticals as those diet supplements that deliver a concentrated form of a presumed bioactive agent in a nonfood matrix and used to enhance health in doses that exceed those that could be obtained from normal foods," he said. "A good example is genistein purified from soybeans and delivered in a pill in doses greater than could be consumed in soy."
Nonfood matrixes include powders, capsules, softgels and gelcaps.
Zeisel's proposals for regulation and testing would benefit manufacturers in the long run as well as the public, he said. A dietary supplement harming a lot of people could result in a public reaction that would damage the entire supplement industry just as the thalidomide debacle injured the drug industry years ago.
"In addition, with no requirement to show efficacy or safety, corporate investments in research and development of better nutraceuticals are unlikely because competitors can jump in without having to amortize the costs of such research," he said. "Although DSHEA has fostered a situation that encourages continued market growth, it has not fully protected the public or fostered an atmosphere conducive to continuous quality improvement through an investment in research."
Until a few years ago, most dietary supplement companies were relatively small, Zeisel said. Now, multibillion dollar companies like Monsanto, Bristol-Myers Squibb, Lipton, Johnson & Johnson, DuPont, Procter & Gamble and Novartis commit major resources to discover health-enhancing properties of foods and to boost those properties. Now too, the American Pharmaceutical Association estimates that 80 percent of U.S. pharmacies sell dietary supplements.
Note: Zeisel can be reached at 919-966-7218 or via e-mail at steven_zeisel@unc.edu
UNC-CH School of Public Health Contact: Lisa Katz, 919-966-8498.
UNC-CH News Services Contact: David Williamson, 919-962-8596.
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Science