RESUMO
PURPOSE: To determine the effects of omega-3 supplementation on liver fat and carotid intima-media thickness (IMT) and to assess accuracy of ultrasound (US) for grading liver steatosis. MATERIALS AND METHODS: In this one-way crossover pilot study, we assigned children with obesity and liver steatosis to receive 1.2 g daily of omega-3 supplementation vs. inactive sunflower oil for 24 or 12 weeks. Liver fat content was assessed by magnetic resonance spectroscopy (MRS), magnetic resonance imaging (MRI) and US, and common carotid IMT by US. Statistical analysis included Chi-square, Student's t-tests, ANOVA tests and receiver operating characteristic (ROC) curves. RESULTS: Omega-3 supplementation was associated with a trend towards decrease in MRS-determined liver fat fraction (0.7% and 2.1% decrease in the 24-week and 12-week omega-3 group, respectively) compared with the sunflower oil group (1.0% increase). These changes were not significant, whether assessed by MRS (P = 0.508), MRI (P = 0.508) or US (P = 0.678). Using US, the area under the ROC curves were 0.964, 0.817 and 0.783 for distinguishing inferred steatosis grades 0 vs. 1-2-3, 0-1 vs. 2-3 and 0-1-2 vs. 3, respectively, indicating good accuracy of US-based fat grading. Omega-3 supplementation was associated with a decrease in US-determined IMT (0.05-mm decrease in the 24-week omega-3 group. A 0.015-mm increase was found in the 12-week omega-3 group, and a 0.007-mm decrease in the sunflower oil group (P = 0.003). CONCLUSION: Omega-3 supplementation had no significant effect on liver fat fraction, but led to carotid IMT decrease in children with obesity and liver steatosis.