Influence of health claim formats on consumer perception in supplement and yoghurt products: a randomized controlled study in Japan

Purpose Health claims on food influence consumer food choices; how different both food forms and formats shape consumer misidentification of food functions with pharmaceutical effects remains unclear. This study aims to evaluate the impact of broad conceptual, direct or combined benefit expressions on consumer perceptions for guiding appropriate health-related claims. Design/methodology/approach An online survey was conducted in Japan from 29 November 2024, involving 900 individuals aged 18–49 years. Participants were randomly assigned to three groups (Format A: Both, B: Broad, C: Direct). The primary outcome was the difference in consumer perceptions such as expectation, clarity and impression among the formats. The secondary outcome was the impact of expectations on misuse for therapeutic purposes. Findings The mean age was 41.1 (SD: 6.8) in Format B, 40.6 (SD: 6.8) in Format C and 39.4 (SD: 7.6) in Format A (p = 0.011). No significant differences were found in consumer perception scores. Expectations in Format A (Exp(β) 3.349, 95%CI: 1.201–9.340, p = 0.021) and C (Exp(β) 2.480, 95%CI: 1.165–5.279, p = 0.018) increased medical use of supplements among health food users. Originality/value More “medicinal” food forms, combined with clear health claims, increase the risk of inappropriate therapeutic use. In contrast, yogurt, despite high consumer appeal, is perceived as a daily food with minimal misuse risk. Therefore, food companies, governments and consumers must consider how the “image of the food based on form” and “health claims” lead to risk of misuse to ensure effective communication.