Relationships between vitamin and mineral supplement use, dietary intake, and dietary adequacy among adolescents

Objective To examine patterns of supplement use among US adolescents and th e relationship between supplement use and dietary intake and adequacy. Design Adolescents self-reported 2 days of food intake using the 24-hour re call method and supplement use during a personal interview conducted as par t of the 1994 Continuing Survey of Food Intakes of Individuals (CSFII). Subjects A national sample of 423 adolescents included in the 1994 CSFII su rvey. Statistical analysis chi (2) analysis was used to determine which demograph ic factors were significantly related to patterns of supplement use. Weight ed percentages of adolescents by category of supplement use for selected vi tamins and minerals (calcium; iron; zinc; folic acid; and vitamins A, B-6, C, and E) are presented. Relationships between dietary intake of macronutri ents and vitamins and minerals among adolescents and supplement use were de termined using a least-squares model of general linear regression. Results Approximately one-third of adolescents reported using supplements, with 15.6% of youth using them on a daily basis. The majority of supplement users reported taking multivitamins (N=95; 65.5%) whereas only one-third o f supplement users reported taking individual vitamins or minerals. Supplem ent use was found to van, by gender, household size, and US region of resid ence. Adolescents who reported using supplements had higher mean dietary in takes of most micronutrients and lower intakes of total and saturated fat t han those who did not use supplements. More than one-third of adolescents h ad dietary intakes of vitamins A and E, calcium, and zinc that were < 75% o f the US Recommended Dietary Allowance. Applications/Conclusions The majority of US adolescents do not use vitamin or mineral supplements. Interestingly, adolescents who do use supplements, evert on an infrequent basis, consume diets that are more nutrient-dense th an those who do not use supplements. Dietary intakes of several micronutrie nts were inadequate among all adolescents in this study, regardless of supp lement use status. There is a need to develop and implement programs aimed at improving the dietary intakes of US adolescents.