Dietary Supplements
Clinical Implications for Dentistry
Diane Rigassio Radler, PhD, RD
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ABSTRACT
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Background. Sales of dietary supplements in the United States continue to increase; patients who seek dental care more than likely are taking or contemplating taking dietary supplements. The author reviews the background of dietary supplements, highlights popular over-the-counter supplements available in the United States and addresses the issues of safety, efficacy and contraindications that merit consideration in clinical practice.
Methods. The author reviewed the literature regarding effectiveness of common dietary supplements and mechanisms of action with drug interactions. The author assessed properties of dietary supplements within the context of clinical implications for oral health care professionals.
Conclusions. Dietary supplement use may be prevalent among patients seeking dental care. While some dietary supplements may be effective and safe, their biological activity may interfere with treatment or medications in oral health care.
Clinical Implications. Oral health care professionals can ascertain patients’ use of dietary supplements and evaluate them with respect to treatment. Resources for additional information are provided.
Key Words: Herbal medicine; diet; drug interactions; U.S. Food and Drug AdministrationAbbreviations: DSHEA: Dietary Supplement Health and Education Act • FDA: Food and Drug Administration • OTC: Over-the-counter
An estimated 50,000 dietary supplements are available to consumers.1 Sales of dietary supplements in the United States rose to more than $22 billion in 2006.2,3 Among prescription drug users, approximately 20 percent also use nonvitamin dietary supplements, and nearly 70 percent of these people do not discuss their supplement use with their health care providers.4 Given the prevalence of use among consumers, the potential side effects and drug interactions of dietary supplements warrant consideration in dental practice. This article provides background information on the regulation and manufacturing of dietary supplements, highlights popular over-the-counter (OTC) supplements and addresses clinical implications relative to dental practice. Vitamin and mineral supplements are not included, as they have been addressed in a separate report.5
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BACKGROUND: DIETARY SUPPLEMENTS
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The Food, Drug, and Cosmetic Act6 regulated dietary supplements until the Dietary Supplement Health and Education Act (DSHEA) of 1994 established natural products such as herbs or other compounds as their own entity, exempting them from the scrutiny of the U.S. Food and Drug Administration’s (FDA) premarket approval of safety or efficacy. The DSHEA defined a dietary supplement as "a product intended to supplement the diet" that includes "a vitamin, a mineral, an herb or other botanical" in the form of a "pill, capsule, tablet or liquid."7 Dietary supplements can be categorized as nutrient supplements (for example, vitamin E), botanical supplements (for example, plant-derived materials such as ginkgo biloba) and "other" supplements (for example, creatine). While dietary supplements are intended to "supplement" the diet, consumers may use them in place of nutritious food or as an adjunct to or replacement for traditional drug therapies in disease management.
Under the provisions of DSHEA, the FDA retains the authority to remove supplements from the market if they are proven unsafe, but only after reports of adverse effects are evident. For example, in 2004 the FDA investigated and banned for sale in the United States stimulants containing ephedrine alkaloids, such as the products Hydroxycut (MuscleTech Research and Development, Mississauga, Ontario, Canada), Metab-O-LITE (Rexall Sundown, Boca Raton, Fla.) and TRIMSPA (Goen Technologies, Whippany, N.J.).8
In June 2007, the FDA published rules for good manufacturing practices for dietary supplement manufacturers pertaining to the handling, packaging, storing and labeling of supplements.9 The rules—with which all manufacturers must comply by June 2010—establish quality control measures to produce supplements that are free of contamination and accidental or intentional mislabeling. Quality assurance of dietary supplement ingredients that may be purchased by the manufacturer from a wholesale source ultimately becomes the manufacturer’s responsibility. The new rules should help protect consumers from unsafe supplements.
Popular dietary supplements in the United States.
Marketing and word of mouth are common determinants of consumers’ dietary supplement purchasing decisions.10 Popular herbs used by adults include echinacea, ginger, ginseng, garlic and St. John’s wort.11 Use patterns may be delineated further by sex, state of health or disease, or stage of life.12–15 For example, the supplements of interest to male high school athletes (amino acids, caffeine, creatine) may be quite different from those important to adults with cardiovascular disease (garlic, omega-3 fatty acids, ginseng). Table 1
provides an overview of common dietary supplements that patients may be taking, highlighting clinical oral/systemic health implications for treatment provided by oral health care professionals.16–19
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FACTORS TO CONSIDER IN PATIENT CARE
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Safety.
Natural products such as dietary supplements may be contaminated during growing or processing or may be mislabeled by the manufacturer, even if unintentionally.9 Because DSHEA allows dietary supplements to be sold without FDA approval, several safety concerns arise:
- – whether the product is free of contamination from compounds such as heavy metals or pharmacological substances;
- – product efficacy;
- – proper representation on the label, including whether the supplement actually contains the amount of the active ingredient stated on the label (as opposed to higher levels that may be dangerous).
Interactions and side effects.
Adverse supplement-drug interactions can occur and affect patients’ well-being.20,21 Interactions may be classified broadly as pharmacodynamic or pharmacokinetic based on the mechanism of action. Interactions arising from a compounding or antagonistic effect as a result of the supplement’s being combined with a biologically active agent (including drug therapies) are referred to as "pharmacodynamic actions."16 For example, ginkgo biloba or garlic combined with the drug warfarin may have additive effects on anticoagulation. Alternatively, pharmacokinetic interactions result from the disruption in normal absorption, distribution, metabolism or elimination as a consequence of biologically active substances. For example, the metabolism of St. John’s wort may interfere with that of acetaminophen or a combination of oxycodone and acetaminophen, rendering the drugs less effective. Table 2 (page 454) depicts common pathways of drug metabolism and examples of drugs within those categories. In general, dietary supplements that inhibit metabolic enzymes result in increased drug concentrations; conversely, supplements that induce metabolic enzymes reduce drug concentrations.
Taking the patient’s history.
Within the dental practice, the oral health care professional easily can ask the patient about his or her dietary supplement use when taking the health history and when updating data on current medication use. As dietary supplements are available OTC, questions regarding their use fit in logically when inquiring about other OTC medications. Using a nonjudgmental approach coupled with an explanation of the rationale for questioning may increase the honesty of the patient’s response. Patients who understand that dental treatment or medications may be affected by their use of dietary supplements may be more forthcoming than those who do not see the relationship.
Refer to the box for additional resources on patient care regarding dietary supplements.
Cost.
Because dietary supplements are OTC products, they usually are not covered by third-party insurance payers and the consumer bears the out-of-pocket expense. Subsequently, this may cause consumers to decide whether to buy the supplement rather than nutritious foods, given that supplement prices may range from a few cents to several dollars per day. "Specialty brands," or those sold through multilevel marketing, may demand higher prices but may not necessarily have proportional quality or efficacy.
Alternative treatment.
Patients may use dietary supplements as complementary therapy in addition to a conventional treatment approach, or they may choose them as an alternative to conventional treatment. Using dietary supplements as alternative treatments always implies that the patient is abandoning standard practice in favor of trying a therapy outside the mainstream.22 As examples, a patient may decline the use of an antidepressant in favor of using St. John’s wort for mild depression, or a patient with nausea may opt for the use of ginger root instead of an antiemetic agent.
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CONCLUSION
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The popularity of dietary supplements and the ease by which they are marketed raise concerns for health care providers. Clinicians should ask questions about dietary supplement use when taking patients’ health history and integrate information about dietary supplements into questions regarding medications, both prescribed and OTC. Knowing what patients may be taking as OTC dietary supplements is important in pre-empting potential interactions with medications or treatment. Clinicians should address safety and regulation of dietary supplements as part of comprehensive patient care.
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FOOTNOTES
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Dr. Radler is an assistant professor, Department of Nutritional Sciences, School of Health Related Professions, and a clinical assistant professor, Department of Diagnostic Sciences, New Jersey Dental School, University of Medicine and Dentistry of New Jersey, 65 Bergen Street, Room 157, Newark, N.J. 07101-1709, e-mail "diane.radler{at}umdnj.edu". Address reprint requests to Dr. Radler.
Disclosure: The author reported no disclosures.
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REFERENCES
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- U.S. Department of Health and Human Services, National Institutes of Health. Office of Dietary Supplements update. "http://dietary-supplements.info.nih.gov/News/ODS_update_-_January_2006.aspx". Accessed Feb. 9, 2008.
- American Dietetic Association. Practice paper of the American Dietetic Association: dietary supplements. J Am Diet Assoc 2005; 105(3):460–470.[Medline]
- Blumenthal M, Ferrier GKL, Cavaliere C. Total sales of herbal supplements in the United States show steady growth. Herbalgram (Journal of the American Botanical Council) 2006;71(Aug–Oct):64–66.
- Gardiner P, Graham RE, Legedza AT, Eisenberg DM, Phillips RS. Factors associated with dietary supplement use among prescription medication users. Arch Intern Med 2006;166(18):1968–1974.[Abstract/Free Full Text]
- Touger-Decker R. Vitamin and mineral supplements: what is the dentist to do? JADA 2007;138(9):1222–1226.[Abstract/Free Full Text]
- U.S. Food and Drug Administration. FDA history. "www.fda.gov/oc/history/default.htm". Accessed Feb. 9, 2008.
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. Dietary Supplement Health and Education Act of 1994. "http://vm.cfsan.fda.gov/~dms/dietsupp.html". Accessed Feb. 9, 2008.
- U.S. Food and Drug Administration. FDA announces rule prohibiting sale of dietary supplements containing ephedrine alkaloids effective April 12. "www.fda.gov/bbs/topics/news/2004/NEW01050.html". Accessed Feb. 9, 2008.
- U.S. Food and Drug Administration. FDA issues dietary supplements final rule. "www.fda.gov/bbs/topics/NEWS/2007/NEW01657.html". Accessed Feb. 9, 2008.
- Bauer BA. Herbal therapy: what a clinician needs to know to counsel patients effectively. Mayo Clin Proc 2000;75(8):835–841.[Abstract]
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- Jellin JM, ed. Natural medicines comprehensive database. "www.naturaldatabase.com". Accessed Feb. 9, 2008.
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- Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St John’s wort on drug metabolism by induction of cytochrome P450 3A4 enzyme. JAMA 2003;290(11):1500–1504.[Abstract/Free Full Text]
- Fugh-Berman A. Herb-drug interactions. Lancet 2000;355(9198): 134–138.[Medline]
- Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: a systematic review. Drugs 2001;61(15):2163–2175.[Medline]
- National Institutes of Health, National Center for Complementary and Alternative Medicine. What is complementary and alternative medicine (CAM)? "http://nccam.nih.gov/health/whatiscam/". Accessed Feb. 9, 2008.
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ABSTRACT
BACKGROUND: DIETARY SUPPLEMENTS
