Dietary Supplements: Questions and Answers

The FDA issues warnings about supplements that pose risks to consumers, including those used for CAM therapies. A sample list is below. The FDA found these products of concern because they:

• Could damage health--in some cases severely
• Were contaminated--with other unlabeled herbs, pesticides, heavy metals, or prescription drugs
• Interacted dangerously with prescription drugs

Examples of Supplements That Have Carried FDA Cautions About Safety (6,7)

• Ephedra
• Kava
• Some "dieter's teas"
• L-tryptophan
• PC SPES and SPES
• Aristolochic acid
• Comfrey
• GHB (gamma hydroxybutyric acid)
• GBL (gamma butyrolactone)
• BD (1,4-butanediol)
• Certain products, marketed for sexual enhancement and claimed to be "natural" versions of the drug Viagra®, which were found to contain an unlabeled drug (sildenafil or tadalafil).

7. Does the Federal Government regulate supplements?
Yes, the Federal Government regulates supplements through the FDA. Currently, the FDA regulates supplements as foods rather than drugs. In general, the laws about putting foods (including supplements) on the market and keeping them on the market are less strict than the laws for drugs. Specifically:

Research studies in people to prove a supplement's safety are not required before the supplement is marketed, unlike for drugs.

The manufacturer does not have to prove that the supplement is effective, unlike for drugs. The manufacturer can say that the product addresses a nutrient deficiency, supports health, or reduces the risk of developing a health problem, if that is true. If the manufacturer does make a claim, it must be followed by the statement "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

The manufacturer does not have to prove supplement quality. Specifically:

The FDA does not analyze the content of dietary supplements.

At this time, supplement manufacturers must meet the requirements of the FDA's Good Manufacturing Practices (GMPs) for foods. GMPs describe conditions under which products must be prepared, packed, and stored. Food GMPs do not always cover all issues of supplement quality.

Some manufacturers voluntarily follow the FDA's GMPs for drugs, which are stricter. Some manufacturers use the term "standardized" to describe efforts to make their products consistent. However, U.S. law does not define standardization. Therefore, the use of this term (or similar terms such as "verified" or "certified") does not guarantee product quality or consistency.

If the FDA finds a supplement to be unsafe once it is on the market, only then can it take action against the manufacturer and/or distributor, such as by issuing a warning or requiring the product to be removed from the marketplace.

In March 2003, the FDA published new proposed guidelines for supplements that would require manufacturers to avoid contaminating their products with other herbs, pesticides, heavy metals, or prescription drugs. The guidelines would also require supplement labels to be accurate. These new guidelines could take effect as early as 2004.

The Federal Government also regulates supplement advertising, through the Federal Trade Commission. It requires that all information about supplements be truthful and not mislead consumers.

What's in the Bottle Does Not Always Match What's on the Label
A supplement might:

• Not contain the correct ingredient (plant species). For example, one study that analyzed 59 preparations of echinacea found that about half did not contain the species listed on the label.8
• Contain higher or lower amounts of the active ingredient. For example, an NCCAM-funded study of ginseng products found that most contained less than half the amount of ginseng listed on their labels.9
• Be contaminated (as discussed in Question 6).

8. Is NCCAM supporting research on supplements?
Yes, NCCAM is funding most of the nation's current research aimed at increasing scientific knowledge about supplements--including whether they work; if so, how they work; and how purer and more standardized products could be developed. Among the substances that researchers are studying are:

• Yeast-fermented rice, to see if it can lower cholesterol levels in the blood
• Soy, to see if it slows the growth of tumors
• Ginger and turmeric, to see if they can reduce inflammation associated with arthritis and asthma
• Chromium, to better understand its biological effects and impact upon insulin in the body, possibly offering new pathways to treating type 2 diabetes
• Green tea, to find out if it can prevent heart disease

NCCAM is also sponsoring or cosponsoring clinical trials on supplements, including:

• Glucosamine hydrochloride and chondroitin sulfate, to find out if they relieve knee pain from osteoarthritis
• Black cohosh, to see if it reduces hot flashes and other symptoms of menopause
• Echinacea, to see if it shortens the length or lessens the severity of colds in children
• Garlic, to find out if it can lower moderately high cholesterol levels
• Ginkgo biloba, to determine whether it prevents or delays decline in cognitive (thinking) function in people aged 85 or older
• Ginger, to confirm whether it eases nausea and vomiting after cancer chemotherapy

Definitions

Amino acid: Building block of proteins.

Botanical: See "herb." "Botanical" is a synonym for "herb."

Clinical trials: Research studies in which a treatment or therapy is tested in people to see whether it is safe and effective.

Depression: An illness that involves the body, mood, and thoughts. The symptoms of depression often include feelings of sadness, hopelessness, or pessimism; and changes in sleep, appetite, and thinking.

Enzymes: Proteins that speed up chemical reactions in the body.

Glandulars: Dietary ingredients or supplements that are made from the glands of animals.

Heavy metals: A class of metals that, in chemical terms, have a density at least five times that of water. They are widely used in industry. A few examples of heavy metals that are toxic and have contaminated some dietary supplements are lead, arsenic, and mercury.

Herb: A plant or plant part that is used for its flavor, scent, and/or therapeutic properties.

Peer reviewed: Reviewed before publication by a group of experts in the same field.

Testimonials: Information provided by individuals who claim to have been helped or cured by a particular product. The information provided lacks the necessary elements to be evaluated in a rigorous and scientific manner and is not used in the scientific literature.

References

1. Dietary Supplement Health and Education Act of 1994. Food and Drug Administration Web site. Accessed at www.fda.gov/opacom/laws/dshea.html on April 14, 2003.
2. Dietary supplements: overview. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition Web site. Accessed at www.cfsan.fda.gov/~dms/supplmnt.html on August 20, 2003.
3. Kaufman DW, Kelly JP, Rosenberg L, et al. Recent patterns of medication use in the ambulatory adult population of the United States: the Slone survey. Journal of the American Medical Association. 2002;287(3):337-344.
4. Federal Trade Commission. Promotions for kids' dietary supplements leave sour taste. Federal Trade Commission Web site. Accessed at www.ftc.gov/bcp/conline/features/kidsupp.pdf on May 2, 2003.
5. Natural Medicines Comprehensive Database. Natural Medicines Comprehensive Database Web site. Accessed at naturaldatabase.com on August 20, 2003.
6. MedWatch: the FDA safety information and adverse event reporting program. U.S. Food and Drug Administration Web site. Accessed at www.fda.gov/medwatch on August 20, 2003.
7. Dietary supplements: warnings and safety information. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition Web site. Accessed at www.cfsan.fda.gov/~dms/ds-warn.html on April 14, 2003.
8. Gilroy CM, Steiner JF, Byers T, et al. Echinacea and truth in labeling. Archives of Internal Medicine. 2003;163(6):699-704.
9. Harkey MR, Henderson GL, Gershwin ME, et al. Variability in commercial ginseng products: an analysis of 25 preparations. American Journal of Clinical Nutrition. 2001;73(6):1101-1106.

National Center for Complementary and Alternative Medicine (NCCAM)
National Institutes of Health
Bethesda, Maryland 20892 USA
Web: nccam.nih.gov
E-mail: info@nccam.nih.gov

NCCAM Publication No. D191
September 2003
Reviewed July 2004

NCCAM has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your primary health care provider. We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy in this information is not an endorsement by NCCAM.