Usability Evaluation of Foods with Function Claims Labelling as Health Information in Japan: A User-Testing Study

Michiko Yamamoto,1,* Ken Yamamoto,2,* Hiromi Takano-Ohmuro,3 Rain Yamamoto,4 Junji Saruwatari1 1Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto-city, Kumamoto, Japan; 2Showa Pharmaceutical University, Machida-city, Tokyo, Japan; 3Faculty of Pharmacy, Musashino University, Nishitokyo-city, Tokyo, Japan; 4Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan*These authors contributed equally to this workCorrespondence: Michiko Yamamoto, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oehonmachi, Chuo-ku, Kumamoto-city, Kumamoto, Japan, Email m-yamamoto@kumamoto-u.ac.jpPurpose: The saturation of health foods in the market is coupled with inadequate information on their safe usage. Recently, health issues caused by Foods with Function Claims (FFCs) have resulted in 81 suspected deaths in Japan, where labelling precautions proved ineffective. We previously developed a Communication Index to assess usability and comprehension of FFC labelling from the perspective of healthcare professionals (HCPs). It is important to explore ways to evaluate and improve labelling usability from the consumers’ perspective to ensure safe usage.Patients and Methods: We conducted user testing from the consumers’ perspective on labels of five different FFCs, utilizing semi-structured interviews with 50 participants of diverse ages and sexes. Two levels of passing criteria were established for accessibility to correct answers: ≥ 90% of all questions within 1 min and 2 min. After the user testing, we qualitatively analyzed the participants’ feedback. Furthermore, we created a revised version of labels, which participants then evaluated against the current version using a 5-point scale.Results: Only one FFC label met the acceptance criteria within 2 min, while none did so within 1 min. The response rate for questions critical to safe use was particularly low, averaging around 70%. Participants’ feedback revealed lack of familiarity with FFCs, suggesting that the terms and text on the labels were often confusing and overly technical.Conclusion: We demonstrated that FFC label assessments from users’ perspective did not meet the passing criteria. User testing offered valuable insights into how FFC labelling can be improved to ensure safer and more appropriate use by aligning with users’ understanding and perceptions. For the first time, we developed a framework that integrates evaluations from both users and HCPs, highlighting the challenges and potential improvements with the FFC label as a source of health information.Keywords: health literacy, food with health claims, safety use, semi-structured interview, risk communication