Millions of Americans use dietary supplements (1,2). Data from national nutrition surveys suggest that approximately 52% of all American adults use dietary supplements (1,3) with substantially higher use among certain population subgroups such as cancer survivors (4–7). One reason for the high prevalence of use is the 1994 passage of Public Law 103–417, the Dietary Supplement and Health Education Act (DSHEA) (8). This legislation discontinued the premarket safety evaluations for ingredients used in supplements, placed the burden of proof of product safety on the US Food and Drug Administration (FDA) instead of the manufacturers and permitted limited nutrition support statements without prior approval from the FDA (8). These regulations resulted in an exponential increase in the number and variety of dietary supplements available for over-the-counter purchase, including those that consumers believe may prevent chronic diseases such as cancer (9–11).