Questionable advisability of vitamin and mineral dietary supplement use in adolescents.

Objective: Present study aimed to assess potential health risk in Slovenian adolescents due to inadequate diet and/or dietary supplement (DS) use.

Methods: Data on DS use, micronutrient intake (24-h recall), eating habits (FFQ), body height and mass were collected within ACDSi (Analysis of Children's Development in Slovenia) cross-sectional study conducted in 2014. Adolescents enrolled in first year of 15 secondary schools (average (SD) age: 15.4 (0.7) years, N = 342) were included in the sample.

Results: Adolescents' use of DS (especially multivitamins ingested as a popular drink (60%), magnesium (16%), and vitamin C (10%)) significantly contributed to their absolute intake of vitamins/minerals, resulting in higher percentage of DS users meeting reference values proposed by the nutrition societies of Germany, Austria, and Switzerland (D-A-CH recommendation). Simultaneously, DS users did not exceed the upper tolerable level proposed by the European Food Safety Authority for daily intake. With diet alone, adolescents consumed less than recommended amounts of the following vitamins/minerals: the intake was lowest for fat-soluble vitamins A, D, and E; water-soluble vitamins folate, biotin, and pantothenic acid; and minerals fluoride, iodine, chromium, and molybdenum. Suboptimal intake was due to the fact that around ¾ of adolescents consumed less than 54% of the recommended amounts (according to Optimized Mixed Diet (OMD) recommendations) for fruits, vegetables, milk/dairy products, fish, and cereals/cereal products. In contrast, the diet contributed to the consumption of 200-300% of D-A-CH minimum value for sodium. Furthermore, almost ¾ of adolescents exceeded the recommended amount for meat/meat products (320% of OMD) and sweet/salty snacks (453% of OMD).

Conclusions: Although DS use improved micronutrient intake in adolescents (especially vitamin C and magnesium), activities on public-health interventions should be focus to improve their diets, especially to achieve increased intakes of fruits, vegetables, cereals/cereal products and milk/dairy products, and to reduce consumption of sweet/salty snacks and meat products.