Objective: Compared to normal weight adolescents, obese adolescents have lower serum omega-3 (n-3) polyunsaturated fatty acid (PUFA) concentrations, augmented inflammatory activity and endothelial dysfunction. We wanted to assess whether n-3 supplementation increases the serum n-3 PUFA concentration, improves vascular function and morphology, and lowers inflammation in obese adolescents.

Methods: Twenty-five obese adolescents (14 females, 11 males, age 15.7±1.0 years, BMI 33.8±3.9) were randomized to receive capsules containing either 1.2g/day n-3 or placebo for 3 months. The study was performed using a double-blind, cross-over design with a 6-week washout period. Anthropometry, blood pressure measurements and fasting blood samples were obtained before and after each treatment period. The vascular structure and function was measured after each treatment period.

Results: The serum n-3 PUFA concentration increased with n-3 treatment. The reactive hyperemia response improved with n-3 treatment compared to placebo (p<0.01). N-3 supplementation also decreased the lymphocyte, monocyte, TNF-α, IL-6 and IL-1β levels. No difference was found in the total cholesterol, triacylglycerol, HDL cholesterol, anthropometry, blood pressure, pulse wave velocity or vascular structure between the two treatment groups.

Conclusion: Daily supplementation with n-3 capsules increases the serum n-3 PUFA concentration, improves vascular function, and lowers the degree of inflammation in obese adolescents.