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Safety Considerations of Dietary Supplements
- Taking any medications (whether prescription or over-the-counter), as some dietary supplements have been found to interact with medications.
- Planning to have surgery. Certain dietary supplements may increase the risk of bleeding or affect the response to anesthesia.
- Pregnant or nursing a baby, or are considering giving a child a dietary supplement. Most dietary supplements have not been tested in pregnant women, nursing mothers, or children.
If you are taking a dietary supplement, read the label instructions. Talk to your health care provider if you have any questions, particularly about the best dosage for you to take. If you experience any side effects that concern you, stop taking the dietary supplement, and contact your health care provider. You can also report your experience to the FDA's MedWatch program. Consumer safety reports on dietary supplements are an important source of information for the FDA.
Keep in mind that although many dietary supplements (and some prescription drugs) come from natural sources, "natural" does not always mean "safe." For example, the herbs comfrey and kava can cause serious harm to the liver. Also, a manufacturer's use of the term "standardized" (or "verified" or "certified") does not necessarily guarantee product quality or consistency.
Be aware that an herbal supplement may contain dozens of compounds and that its active ingredients may not be known. Researchers are studying many of these products in an effort to identify active ingredients and understand their effects in the body. Also consider the possibility that what's on the label may not be what's in the bottle. Analyses of dietary supplements sometimes find differences between labeled and actual ingredients. For example:
- An herbal supplement may not contain the correct plant species.
- The amount of the active ingredient may be lower or higher than the label states. That means you may be taking less—or more—of the dietary supplement than you realize.
- The dietary supplement may be contaminated with other herbs, pesticides, or metals, or even adulterated with unlabeled ingredients such as prescription drugs.
For current information from the Federal Government on the safety of particular dietary supplements, check the "Dietary Supplement and Safety Information" section of the FDA Web site at www.fda.gov/Food/DietarySupplements/Alerts/ or the "Alerts and Advisories" section of the NCCAM Web site at nccam.nih.gov/news/alerts.
Dietary Supplements Research at the National Institutes of Health
NCCAM, which is part of the NIH, is the Federal Government's lead agency for studying all types of CAM. As part of that role, the Center sponsors a wide array of research to see how dietary supplements might affect the body and tests their use in clinical trials. In fiscal year 2007, NCCAM supported more than 200 research projects studying dietary supplements, including herbs and botanicals.
Also within NIH, the ODS focuses specifically on dietary supplements, seeking to strengthen knowledge by supporting and evaluating research, disseminating results, and educating the public.
NCCAM and ODS collaborate to fund dietary supplement research centers focused on botanicals, known collectively as the NIH Botanical Research Centers Program. Scientists at the centers conduct basic research and other studies on botanicals and help to select products to be tested in clinical trials. The centers are advancing the scientific base of knowledge about botanicals, making it possible to better evaluate their safety and effectiveness.
NCCAM also sponsors a number of Centers of Excellence for Research on CAM, including centers studying antioxidant therapies, botanicals for autoimmune and inflammatory diseases, grape-derived polyphenols for Alzheimer's disease, and botanicals for pancreatic diseases and for colorectal cancer.
- Barnes PM, Bloom B, Nahin R. Complementary and alternative medicine use among adults and children: United States, 2007. CDC National Health Statistics Report #12. 2008.
- Dietary Supplement Health and Education Act of 1994. U.S. Food and Drug Administration Web site. Accessed athttps://www.fda.gov/RegulatoryInformation/Legislation/ on May 12, 2008.
- Dietary supplements: background information. Office of Dietary Supplements Web site. Accessed at ods.od.nih.gov/factsheets/DietarySupplements_pf.asp on November 18, 2008.
- Dietary supplements: overview. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition Web site. Accessed atwww.fda.gov/Food/DietarySupplements/ on May 12, 2008.
- Natural Medicines Comprehensive Database. Product monographs. Accessed at www.naturaldatabase.com on May 13, 2008.
- Radimer K, Bindewald B, Hughes J, et al. Dietary supplement use by US adults: data from the National Health and Nutrition Examination Survey, 1999–2000.American Journal of Epidemiology. 2004;160(4):339–349.
For More Information
The NCCAM Clearinghouse provides information on CAM and NCCAM, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
Toll-free in the U.S.: 1-888-644-6226
TTY (for deaf and hard-of-hearing callers): 1-866-464-3615
Web site: nccam.nih.gov
Office of Dietary Supplements (ODS)
ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as What Dietary Supplements Are You Taking?), fact sheets on a variety of specific supplement ingredients (such as vitamin D and black cohosh), and the International Bibliographic Information on Dietary Supplements (IBIDS) database.
Web site: www.ods.od.nih.gov
U.S. Food and Drug Administration (FDA)
The FDA oversees the safety of many products, such as foods, medicines, dietary supplements, medical devices, and cosmetics. Its series of consumer updates includes the publication FDA 101: Dietary Supplements.
Web site: www.fda.gov
Toll-free in the U.S.: 1-888-463-6332
Center for Food Safety and Applied Nutrition (CFSAN)
CFSAN oversees the safety and labeling of supplements, foods, and cosmetics. Online resources for consumers include "Tips for the Savvy Supplement User: Making Informed Decisions and Evaluating Information" and dietary supplement safety alerts.
Web site: www.fda.gov/AboutFDA/CentersOffices/CFSAN/
Toll-free in the U.S.: 1-888-723-3366
MedWatch, the FDA's safety information and adverse event reporting program, allows consumers and health care providers to file reports on serious problems suspected with dietary supplements.
Web site: www.fda.gov/Safety/MedWatch/HowToReport/ucm053074.htm
Toll-free in the U.S.: 1-888-463-6332
Federal Trade Commission (FTC)
The FTC is the Federal agency charged with protecting the public against unfair and deceptive business practices. A key area of its work is the regulation of advertising (except for prescription drugs and medical devices).
Web site: ftc.gov
Toll-free in the U.S.: 1-877-382-4357
A service of the National Library of Medicine (NLM), PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. CAM on PubMed®, developed jointly by NCCAM and NLM, is a subset of the PubMed® system and focuses on the topic of CAM.
Web site: www.ncbi.nlm.nih.gov/sites/entrez
CAM on PubMed®: nccam.nih.gov/research/camonpubmed/
National Library of Medicine's MedlinePlus and
Dietary Supplements Labels Database
To provide resources that help answer health questions, MedlinePlus brings together authoritative information from the National Institutes of Health as well as other Government agencies and health-related organizations.
Web site: www.medlineplus.gov
The Dietary Supplements Labels Database provides information about ingredients in more than 2,000 selected brands of dietary supplements, including vitamins, minerals, herbs or other botanicals, amino acids, and other specialty supplements.
Web site: dietarysupplements.nlm.nih.gov/dietary
NCCAM thanks Jack Killen, M.D., and Carol Pontzer, Ph.D., NCCAM, for their review of this publication. NCCAM also thanks the ODS for its review.
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 is not an endorsement by NCCAM.