Patient use of dietary supplements: a clinician's perspective

The estimated prevalence of dietary-supplement use among US adults was 73% in 2002. Appropriate use of dietary supplements within the paradigm of evidence-based medicine may be a challenge for medical doctors and non-physician clinicians. Randomized, controlled, clinical trial data, which are considered the gold standard for evidence-based decision making, are lacking. Standardized guidelines for the use of dietary supplements are lacking, and dietary supplements can bear unsupported claims.

This article is intended to review clinically-relevant issues related to the widespread use of dietary supplements, with emphasis on regulatory oversight and safety.

Review articles and clinical trial articles published up until December 2007 were selected based on a search of the MEDLINE electronic database using PubMed. The Food and Drug Administration (FDA) Website was also used as a resource. We used the search terms dietary supplement(s), vitamin supplements, mineral supplements, and Dietary Supplement and Health Education Act. Articles discussing dietary supplements and their regulation, prevalence of use, prescription and nonprescription formulations, and/or adverse events were selected for review. Articles discussing one or more of these topics in adults were selected for inclusion.

New FDA regulations require dietary-supplement manufacturers to evaluate the identity, purity, strength, and composition of their products. However, these regulations are not designed to demonstrate product efficacy and safety, and dietary-supplement manufacturers are not required to submit efficacy and safety data to the FDA prior to marketing. Product contamination and/or mislabeling may undermine the integrity of dietary-supplement formulations.

The use of dietary supplements may be associated with adverse events. Although there are new regulatory requirements for dietary supplements, these products will not require FDA approval or submission of efficacy and safety data prior to marketing under the new regulation. A limitation to the literature used for this review is the lack of prospective, randomized clinical trials on the safety and efficacy of dietary supplements. Clinicians should be aware of all the dietary supplements that their patients consume, and help their patients make informed decisions appropriate to their medical care.