Objectives: A few previous studies have described a potential role of Ω-3 long-chain polyunsaturated fatty acids from marine animals in obesity in children, but the results are conflicting. The objectives of this study were to examine if intake of marine fat was related to less gain in body mass index (BMI) and body fat (BF) over a 15-mo period among Danish children age 2 to 6 y, and if potential associations depended on which types of fatty acids were replaced.

Methods: A total of 355 children age 2 to 6 y were included in the study. Weight, height, and BF percentage (BF%) assessed by bioimpedance were measured by trained research personnel. Multivariable linear regression models were used to investigate associations between marine fat intake and changes in BMI or BF% over the subsequent 15 mo. To investigate substitution effects, we constructed regression models that included marine fat and all other energy yielding dietary components, except for the nutrient to be substituted for either all fats or specific subgroups (saturated, monounsaturated, or other polyunsaturated fatty acids).

Results: No significant associations were observed between intake of marine fat and development in BMI or BF% in any of the analyses, either with or without specified substitutions. Furthermore, the results were independent on whether intake was expressed in g/d or percentage of energy, and were not modified by age or BMI status.

Conclusions: This study suggests that marine fat intake and fat composition in a diet may have little or no effect on weight and adiposity development among preschool-aged children.