Does the evidence make a difference in consumer behavior? Sales of supplements before and after publication of negative research results.
OBJECTIVE
To determine if the public consumption of herbs, vitamins, and supplements changes in light of emerging negative evidence.


METHODS
We describe trends in annual US sales of five major supplements in temporal relationship with publication of research from three top US general medical journals published from 2001 through early 2006 and the number of news citations associated with each publication using the Lexus-Nexis database.


RESULTS
In four of five supplements (St. John's wort, echinacea, saw palmetto, and glucosamine), there was little or no change in sales trends after publication of research results. In one instance, however, dramatic changes in sales occurred following publication of data suggesting harm from high doses of vitamin E.


CONCLUSIONS
Results reporting harm may have a greater impact on supplement consumption than those demonstrating lack of efficacy. In order for clinical trial evidence to influence public behavior, there needs to be a better understanding of the factors that influence the translation of evidence in the public.
Tilburt
Jon C
JC
Department of Bioethics, National Institutes of Health, Bethesda, MD, USA. tilburt.jon@mayo.edu
Emanuel
Ezekiel J
EJ
Miller
Franklin G
FG
D003132:Commerce / Q000639:trends; D003258:Consumer Behavior; D003257:Consumer Product Safety; D019587:Dietary Supplements / Q000009:adverse effects* / Q000706:statistics & numerical data*; D015438:Health Behavior; D006801:Humans; D016896:Treatment Outcome; D014481:United States