Abstract
OBJECTIVE: This study aimed to investigate the potential of LINE, a major messaging app and social media platform in Japan, as an effective tool to enhance the health and dietary behaviors of young Japanese women who face health and dietary challenges. METHODS: A 6-week randomized controlled trial employing an intention-to-treat analysis was conducted on first-year female students (age range, 18-23 years) from one university and two junior colleges in Mie Prefecture. The participants were allocated to either an intervention group (n = 54) or a control (n = 55) group. The intervention group received health information focusing on proper intake and intake methods to maintain an appropriate weight and dietary balance via LINE 18 times over 6 weeks (3 times per week), whereas the control group continued their usual lifestyle without any additional intervention. RESULTS: The results revealed a significant increase in the percentage of participants in the intervention group who rated their health as "unhealthy" (from 25.9% to 40.3%). This may be attributed to increased health awareness among the participants, which led to more critical self-assessments-a phenomenon often referred to as the "health awareness paradox." Despite this increase in perceived unhealthiness, the intervention group showed a significant increase in the intakes of iron, vitamin C, dietary fiber, and potassium, indicating improved nutritional behavior. CONCLUSION: The provision of health information through LINE over a 6-week period demonstrated potential as a tool for health education among young Japanese women. However, the observed increase in "unhealthy" self-rated health underscores the complexity of such interventions, suggesting that while nutritional behavior may improve, increased health awareness can paradoxically lead to more negative self-assessments. Further research is needed to explore the optimal duration and content of health information delivered via social media apps to maximize their effectiveness for health interventions.