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.