Bozbulut R, Şanlıer N, Döğer E, et al. - This study was undertaken to determine if supplemental soluble fiber, oat β-glucan, has any impact on glycemic control and variability of adolescents with type 1 diabetes mellitus. The sample consisted of 30 adolescents with type 1 diabetes mellitus and it consisted of three phases lasting one week. All individuals followed a standard diet program at Phase I. The participants continued their standard diet program and added natural oat flakes containing 3 g/day and 6 g/day β-glucan, respectively, for Phase II and Phase III. At Phase III, the maximal, mean and daytime and night blood glucose levels were the lowest. At Phase III, minimal blood glucose levels were the highest. In adolescents with type 1 diabetes mellitus, 6 g/day oat β-glucan have favorable outcomes in glycemic control and variability.