Qualified health claims: Communicating scientific certainty about functional food relationships

The US Food and Drug Administration (FDA) regulates and authors qualified health claims (QHCs) for voluntary use by companies on food and dietary supplement labels. QHCs communicate the scientific certainty about diet-disease relationships that are not supported by significant scientific agreement among qualified experts. These claims emerged from a federal lawsuit that ruled QHCs a First Amendment issue.;Several lawsuits about the description of evidence (i.e. disclaimer) in QHCs led to case law and technical regulatory documents. The FDA must write more than one clear and succinct QHC for the same diet-disease relationship, and the disclaimer may not contradict the diet-disease relationship. However, research indicates consumers are confused by QHCs and are rarely used.;To catalogue their description of scientific certainty, a content analysis parsed the 53 currently-enforced QHCs. Thirty-six formats to communicate scientific evidence were found. Most demonstrate a reading level above 9th grade, describe the quality of evidence ("very weak") and/or reference its consistency, while a quarter quantify the evidence ("two studies").;A 2012 lawsuit over green tea QHCs prompted an investigation of seven QHCs pertaining to a green tea-cancer relationship designed to test stakeholder's assumptions and arguments from the lawsuit and to understand the potential benefit of QHCs to companies. An online experiment was used to assess and to directly compare consumer comprehension of the scientific support implied by each of the claims and resulting intentions to purchase green tea.;Overall, consumers understood the level of evidence for the green tea-cancer relationship. Consumers who had made health-related dietary changes and considered health claims important reported greater purchase intentions after reading a green tea-cancer QHC. Consumers who read a claim written by the green tea company perceived greater evidence for the green tea-cancer relationship, were more confident in the relationship, and reported greater purchase intentions than others. The currently enforced QHC resulted in lower scores for perceived level of evidence for and confidence in the green tea-cancer relationship, and purchase intentions for green tea when compared with QHCs written by the green tea company and higher scores when compared to other FDA QHCs. The current QHC appears to be a compromise between claims written by the green tea company and other QHCs written by FDA.