Original Article

Medical Residents’ Knowledge of Dietary Supplements

Authors: Bimal H. Ashar, MD, MBA, Tasha N. Rice, MHS, Stephen D. Sisson, MD


Introduction: The widespread use of complementary and alternative medicine modalities such as dietary supplements has prompted many medical schools to offer courses covering such topics. To date, little is known about the impact of these courses on medical graduates’ knowledge. This study was designed to evaluate resident physicians’ level of understanding of popular dietary supplement regulation and to determine whether an interactive online curriculum could aid in improving such knowledge.

Methods: A multicenter online educational intervention was developed and administered to physicians at 15 internal medicine residency programs throughout the United States, between March 1, 2006 and June 30, 2006. Pretest performance was used to measure baseline knowledge of commonly used dietary supplements. Posttest performance compared with pretest performance measured the effectiveness of the educational intervention.

Results: A total of 335 physicians completed the module. Baseline knowledge of dietary supplements was low (average pretest score 59.7%). More than one-third of respondents were unaware of the reasons for use of saw palmetto and black cohosh. Results for questions on safety and drug-supplement interactions were similarly low. Only 57% of physicians knew that kava kava has been associated with hepatitis. Only 15% were aware that St. John’s Wort can lower cyclosporine levels. With regards to knowledge of efficacy, only 36% were aware that fish oil has been shown to lower triglyceride levels. After completion of the curriculum, scores improved significantly (P < 0.001) in all question/content areas.

Conclusions: Residents’ knowledge of dietary supplements is poor. An online didactic module may improve knowledge and potentially enhance patient-physician communication regarding the use of such products.

This content is limited to qualifying members.

Existing members, please login first.

If you have an existing account please login now to access this article or view your purchase options.

Purchase only this article ($15)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.


1. Barnes PM, Powell-Griner E, McFann K, et al. Complementary and Alternative Medicine use Among Adults: United States, 2002. Advance Data from Vital and Health Statistics; no 343. Hyattsville, Maryland, National Center for Health Statistics, 2004. Available at: http://www.cdc.gov/nchs/data/ad/ad343.pdf. Accessed August 22, 2008.
2. Eisenberg DM, Davis RB, Ettner SL, et al. Trends in alternative medicine use in the United States, 1990–1997: results of a follow-up national survey. JAMA 1998;280:1569–1575.
3. Radimer K, Bindewald B, Hughes J, et al. Dietary supplement use by U.S. adults: data from the National Health and Nutrition Examination Survey, 1999–2000. Am J Epidemiol 2004;160:339–349.
4. Timbo BB, Ross MP, McCarthy PV, et al. Dietary supplements in a national survey: prevalence of use and reports of adverse events. J Am Diet Assoc 2006;106:1966–1974.
5. Kligler B, Maizes V, Schachter S, et al. Core competencies in integrative medicine for medical school curricula: a proposal. Acad Med 2004;79:521–531.
6. Wetzel MS, Kaptchuk TJ, Haramati A, et al. Complementary and alternative medical therapies: implications for medical education. Ann Intern Med 2003;138:191–196.
7. Frenkel M, Ben Arye E. The growing need to teach about complementary and alternative medicine: questions and challenges. Acad Med 2001;76:251–254.
8. Barzansky B, Etzel SI. Educational programs in US medical schools, 2003–2004. JAMA 2004;292:1025–1031.
9. Wetzel MS, Eisenberg DM, Kaptchuk TJ. Courses involving complementary and alternative medicine at US medical schools. JAMA 1998;280:784–787.
10. Brokaw JJ, Tunnicliff G, Raess BU, et al. The teaching of complementary and alternative medicine in U.S. medical schools: a survey of course directors. Acad Med 2002;77:876–881.
11. Kern DE, Thomas PA, Howard DM, et al. Curriculum Development for Medical Education: A Six-Step Approach. Baltimore, MD, Johns Hopkins University Press, 1998.
12. Sisson SD, Hughes MT, Levine D, et al. Effect of an internet-based curriculum on postgraduate education. A multicenter intervention. J Gen Intern Med 2004;19(5 Pt 2):505–509.
13. Balk E, Chung M, Lichtenstein A, et al. Effects of omega-3 fatty acids on cardiovascular risk factors and intermediate markers of cardiovascular disease. Evid Rep Technol Assess (summ) 2004;93:1–6.
14. Mikail CN, Hearney E, Nemesure B. Increasing physician awareness of the common uses and contraindications of herbal medicines: utility of a case-based tutorial for residents. J Altern Complement Med 2003;9:571–576.
15. Kemper KJ, Amata-Kynvi A, Sanghavi D, et al. Randomized trial of an internet curriculum on herbs and other dietary supplements for health care professionals. Acad Med 2002;77:882–889.
16. Kemper KJ, Amata-Kynvi A, Dvorkin L, et al. Herbs and other dietary supplements: healthcare professionals’ knowledge, attitudes, and practices. Altern Ther Health Med 2003;9:42–49.
17. Silverstein DD, Spiegel AD. Are physicians aware of the risks of alternative medicine? J Community Health 2001;26:159–174.
18. Palmer ME, Haller C, McKinney PE, et al. Adverse events associated with dietary supplements: an observational study. Lancet 2003;361:101–106.
19. Clouatre DL. Kava kava: examining new reports of toxicity. Toxicol Lett 2004;150:85–96.
20. Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000;343:1833–1838.
21. 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. JAMA 2002;287:337–344.
22. Yue QY, Bergquist C, Gerden B. Safety of St John’s wort (Hypericum perforatum). Lancet 2000;355:576–577.
23. Piscitelli SC, Burstein AH, Chaitt D, et al. Indinavir concentrations and St John’s wort. Lancet 2000;355:547–548.
24. Sugimoto K, Ohmori M, Tsuruoka S, et al. Different effects of St John’s wort on the pharmacokinetics of simvastatin and pravastatin. Clin Pharmacol Ther 2001;70:518–524.
25. Eisenberg DM. Advising patients who seek alternative medical therapies. Ann Intern Med 1997;127:61–69.