CHICAGO--How do dietary supplements differ from drugs, food additives, and food ingredients in classification and regulation? Are the safety and efficacy of supplements ensured? What are the differences between drug claims and health claims on supplement labels? What is required on the new "Supplement Facts" panel? What are the potential benefits and adverse effects of supplements? What do scientists know about drug-supplement interactions? The Institute of Food Technologists' (IFT's) Scientific Status Summary "Dietary Supplements: Nutritional and Legal Considerations" addresses these and other key questions, summarizing information to date on vitamins, minerals, amino acids, botanicals, and dietary hormones.
The Dietary Supplement Health and Education Act (DSHEA) of 1994 provides the regulatory framework for supplements. According to IFT's summary, published in the July 1999 issue of Food Technology, this act broadened the definition of supplements to include ingredients not recognized as traditional nutrients, such as botanicals and hormones.
"Prior to DSHEA, these ingredients could have been challenged by the FDA as unapproved food additives, [but they are now] exempt from additive regulations applicable to conventional foods," note summary authors Mary Ellen Camire, Ph.D., University of Maine, and Mark A. Kantor, Ph.D., University of Maryland.
Unlike drugs and additives, which must undergo rigorous scientific testing for safety and efficacy and FDA pre-market approval, supplements have no formal regulatory requirements prior to being marketed and sold. Although supplement manufacturers should ensure that their products are safe and be able to provide information to support any labeling claims, the FDA bears the burden of showing that a supplement is unsafe or mislabeled before it can restrict or ban the product's use, say Camire and Kantor.
"The passage of DSHEA has created an economic and regulatory environment favorable to the expanded marketing, sales, and distribution of dietary supplements," they note. "Opportunities for consumers to purchase supplements in a free market economy are vastly increased, but [false] expectations remain that government agencies provide [consumer] protection from unsafe or mislabeled products. One of the future challenges with respect to supplements will be to reconcile these apparently opposing forces."
Although foods typically contain safe levels of vitamins and minerals, which are essential to metabolic functions in the body, excessive intake of supplements containing iron or vitamins A, B6, C, D and niacin can be hazardous, state Camire and Kantor. However, they note that certain vitamin and mineral supplements may be necessary for people with chronic illnesses, women of child-bearing age (folic acid), pregnant women (iron), people with iron-deficiency anemia, and people who do not obtain the adult Dietary Reference Intake of 1,000 to 1,200 milligrams of calcium per day in their diets or who are at risk for osteoporosis.
"Many health professionals advise the routine use of calcium and/or vitamin D supple-ments to help prevent osteoporosis, especially for high-risk or elderly individuals," they say.
But other dietary supplements, such as amino acids, may not be beneficial for healthy persons, and in fact, may do more harm than good, according to Camire and Kantor. Health claims associated with chromium picolinate, creatine and androstenedione (formerly used by baseball slugger Mark McGuire) have not been scientifically substantiated, they say. In fact, adverse side effects have been reported for the latter two as well as for dehydroepiandrosterone (DHEA), banned by the International Olympic Committee as an illegal steroid. Certain herbal teas, such as comfrey, have also caused adverse effects. Serious health consequences, including deaths, have been reported for the herb ephedra, also known as ma huang, and products chemically related to gamma-butyrolactone (GBL) and gamma-hydroxybutyric acid (GHB). Risks are also associated with interactions between supplements and certain drugs, such as anti-cancer agents, although not much is known about these interactions, note Camire and Kantor.
Moreover, "although nearly half of the adults in the United States regularly consume dietary supplements, relatively little data exist on the physiological effects of many available products," they say. "Fortunately, the growing popularity of dietary supplements should spur additional, much-needed research on optimal dosages, interactions with drugs and food components, and the relationships between supplements, health maintenance and chronic disease prevention in persons of different genders and ages."
For a copy of IFT's summary on dietary supplements, contact Angela Dansby.
Mary Ellen Camire, Ph.D., is Associate Professor, Department of Food Science and Human Nutrition, at the University of Maine. Mark A. Kantor, Ph.D., is Associate Professor and Extension Specialist, Department of Nutrition and Food Science, at the University of Maryland.