They are advertised in every media channel, from television infomercials to radio spots plugged by local radio personalities. You can get them online, in grocery stores and from kiosks in malls across the country.
With the increasing prevalence of obesity in Americans, it's no wonder that the market for dietary supplements is growing so rapidly.
According to the 1999 National Health and Nutrition Examination Survey, an estimated 61 percent of U.S. adults are either overweight or obese, a 5 percent increase from the 1988-94 survey.
Dietary supplements are defined by the Food and Drug Administration as any product taken by the mouth that contains a dietary ingredient, which may include vitamins, minerals, herbs, amino acids, enzymes, organ tissues, metabolites, extracts or concentrates.
A 2001 Reuters News Service report states that dietary supplement sales are a booming business, growing from $8.6 billion in 1994, to $16 billion last year.
Many dietary supplements, such as Metabolife, claim to promote weight loss. The different brands vary their ingredients, but most contain some form of stimulant, most commonly ephedrine or chromium, according to the U.S. National Library of Medicine.
Over-the-counter weight loss products differ from prescription medications, such as Meridia or Xenical. Carol Mitchell, U of M consumer science and education professor, said that over-the-counter dietary supplements are not subject to the same testing and regulation that prescription drugs must undergo before they are marketed.
According to the FDA, the reason for this is that they have limited resources that don' t allow them to analyze all food products.
"The FDA does not analyze supplement products before they are sold to consumers," the FDA web site states.
The stimulants in dietary supplements increase the heart rate and nervous system functions, which cause the appetite suppression. There have been numerous reports of injuries in relation to the taking of dietary supplements, including high blood pressure, heart rhythm irregularities, strokes, insomnia, seizures, tremors and nervousness, according to the web site MedicineNet.com.
"We certainly know that ephedrine has known health risks for some individuals," Mitchell said. "But there are some people who feel that it is fine."
Richard Kreider, human movement sciences and education associate professor, said the FDA has been trying to pull over-the-counter weight loss supplements from the market for about 8 years.
"There are differences of opinion about the safety of these products," Kreider said. "There have been lots of reports of problems when people take too much."
Kreider believes weight loss supplements are safe when taken as indicated on the label, and advises people to consult with their physician before trying them.
"Taking a weight loss supplement is like drinking too much coffee or a Surge," Krieder.
With so many dietary supplements on the market and so little regulation of them by the FDA, consumers should be careful when taking these products.
"The manufacturer is responsible for ensuring that the ingredient list is accurate and that the ingredients are safe," the FDA web site states.
