Objective: To investigate whether dietary supplementation with docosahexaenoic acid (DHA) decreases liver fat content in children with non-alcoholic fatty liver disease (NAFLD).

Design, setting and patients: We performed a randomised controlled trial of DHA supplementation (250 and 500 mg/day) versus placebo in 60 children with biopsy-proven NAFLD (20 children per group).

Main outcome measures: The main outcome was the change in liver fat content as detected by ultrasonography after 6 months of treatment. Secondary outcomes were the changes in insulin sensitivity index, alanine transaminase, triglycerides and body mass index after 6 months of treatment.

Results: Blood DHA increased in children supplemented with DHA (0.65%, 95% CI 0.30% to 1.10% for the DHA 250 mg group and 1.15%, 0.87% to 1.43% for the DHA 500 mg group). The odds of more severe versus less severe liver steatosis after treatment was lower in children treated with DHA 250 mg/day (OR = 0.01, 0.002 to 0.11, p <0.001) and DHA 500 mg/day (OR = 0.04, 0.002 to 0.46, p = 0.01) as compared to placebo but there was no difference between the DHA groups (p = 0.4). Insulin sensitivity index increased and triglycerides decreased to a similar degree in both DHA groups as compared to placebo but there was no effect on alanine transaminase and body mass index.

Conclusion: DHA supplementation improves liver steatosis and insulin sensitivity in children with NAFLD.