one or more dietary ingredients. Examples of dietary
ingredients includevitamins,minerals, herbs or other
biological material, amino acids, and enzymes. Diet-
ary supplements are sold in the form of tablets, cap-
sules, powders, liquids, extracts, or teas. Products sold
as dietary supplements are required to be clearly
labeled as such.PurposeDietary supplements serve a wide range of pur-
poses. Some of these are medically appropriate, while
others may do nothing or harm the individual. Rea-
sons for taking dietary supplements include:
Replacing a necessary substance not found in large
enough quantities in the diet
Preventing or decreasing the risk of developing a
disease or condition
Boosting the immune system and improving general
health
Boosting energy levels
Improving mental or physical performance
Stimulating weight loss
Reducing symptoms of a disease or health conditionDescription
Dietary supplements comprise a variety of prod-
ucts ranging from familiar multivitamins found in every
supermarket to exotic botanicals such as the South
African herbhoodia. Millions of Americans take diet-
ary supplements daily; their use has become increas-
ingly common since the 1990s. The United States Food
and Drug Administration (FDA) estimates that in 1999
more than 12 million Americans were takingephedra,aweight-loss supplement that was later banned because it
can cause serious side effects. Due to the large number
of different supplements and their range of uses, testing
and regulation of these products is difficult and often
ineffective.Dietary supplements and the law
The FDA regulates dietary supplements under the
1994 Dietary Supplement Health and Education Act
(DSHEA). At the time the act was passed, legislators
believed that because many dietary supplements come
from natural sources such as plants and have been
used for hundreds of years by practitioners of comple-
mentary and alternative medicine (CAM), these prod-
ucts did not need to be as rigorously regulated as
prescription and over-the-counter drugs used in con-
ventional medicine.
DSHEA regulates supplements in the same way
food is regulated. Like food manufacturers, manufac-
turers of dietary supplements do not have to prove that
a supplement is either safe or effective before it can be
sold to the public. Manufacturers of conventional phar-
maceutical drugs, however, must prove both safety and
effectiveness in humans before a new drug is approved
for use. With dietary supplements, the burden of proof
falls on the FDA to show that the supplement is either
unsafe or ineffective before the supplement can be
restricted or banned. Information about a supplement’s
safety and effectiveness is normally gathered only after
people using the product develop health problems or
complain that the product does not work. Initially,
supplement manufacturers were not required to report
consumer complaints of complications or side effects to
the FDA. However, beginning in 2007, a federal law
requires all manufacturers of dietary supplements and
over-the-counter drugs to report consumer complaints
of adverse events (negative side effects) to the FDA.
This makes accumulating information on the safety of
these products faster and easier.
Dietary supplements are required to be clearly
labeled with the word ’’supplement.‘‘ The label must
also show the volume or weight of the contents, the
serving size, a list of dietary ingredients and non-
dietary ingredients (e.g., artificial color, binders, fillers,
flavorings), the name of the manufacturer, packer, or
distributor, and directions for use. If the supplement is
an herb, the label must contain its scientific name.
Unlike conventional drugs, the label for a dietary
supplement does not have to provide statements about
possible side effects. However, dietary supplements
are not legally allowed to claim they can ‘‘cure,’’Drug interactionsDietary supplement Drug
Calcium Heart medicine (e.g., Digoxin) thiazide diuretics
(Thiazide, and aluminum- and magnesium-
containing antiacids)
Magnesium Thiazide and loop diauretics (e.g., Lasiz®), some
cancer drugs (Cisplatin), and magnesium-
containing antiacids.
Vitamin K Blood thinners (e.g., Coumadin)
St. John’s Wort Selective serotonin reuptake inhibitor (SSRI)
drugs (antidepressant drugs and birth control
pills)SOURCE: Office of Dietary Supplements, National Institutes of
Health, U.S. Department of Health and Human Services(Illustration by GGS Information Services/Thomson Gale.)Dietary supplements