A Nationwide Survey of the Attitudes toward the Use of Dietary Supplements among Japanese High-School Students.

We previously studied the prevalence of dietary supplement use in Japanese high-school students by conducting a study on mothers. However, there is often a discrepancy between mothers' understanding and children's attitudes. Thus, we conducted an internet survey of high-school students to clarify their attitudes toward the use of dietary supplements. An invitation to the internet survey was e-mailed to registrants of a research company aged 15 to 18 years. A total of 1031 students (276 male, 755 female) answered the questionnaire on a first come, first served basis. The participants were classified according to the purchasers of their supplements: students who purchased supplements themselves were defined as active users, and others were defined as passive users. The prevalence of dietary supplement use was 30.8% in males and 26.7% in females. Among the users, 42.4% of males and 43.8% of females were active users. Males used supplements for health regardless of active or passive use. However, in females, more active users (40.9%) used supplements for weight loss than passive users (20.4%); the corresponding prevalence was 2.3% in our previous report on mothers' understanding of their daughters. The most frequently used source of information for active users was the internet, whereas for passive users it was family. The frequency of adverse events was 9.4% in males and 14.4% in females, with gastrointestinal symptoms being the most commonly experienced events. Our results suggest that dietary education, including healthy eating and the appropriate use of dietary supplements, should be provided to high-school students.