An examination of structure-function claims in dietary supplement advertising in the U.S.: 2003-2009

Abstract

Dietary supplement advertising cannot claim a causal link between the product and the treatment, prevention, or cure of a disease unless manufacturers seek approval from the FDA for a health claim. Manufacturers can make structure-function (S-F) claims without FDA approval linking a supplement to a body function or system using words such as "may help" or "promotes." These S-F claims are examined in this study in order to determine whether they mimic health claims for which the FDA requires stricter scientific evidence. Data include S-F claims in supplement advertisements (N=6179) appearing in US nationally circulated magazines (N=137) from 2003 to 2009. All advertisements were comprehensively coded for S-F claims, seals of approval, and other claims of guarantee. S-F claims associate supplements with a wide variety of health conditions, many of which are serious diseases and/or ailments. A significant number of the specific verbs used in these S-F claims are indicative of disease treatment/cure effects, thereby possibly mimicking health claims to the average consumer. The strength of the clinical associations made are largely unsubstantiated in the medical literature. Claims that a product is "scientifically proven" or "guaranteed" were largely unsubstantiated by clinical literature. Ads carrying externally validating seals of approval were highly prevalent. S-F claims that strongly mimic FDA-prohibited health claims are likely to create confusion in interpretation and possible public health concerns are discussed.

Keywords: Advertising; Dietary supplements; Health promotion; Vitamins.