Summary Background Non-alcoholic fatty liver disease (NAFLD) affects 10-35% of the adult population worldwide; there is no consensus on its treatment. Omega-3 fatty acids have proven benefits for hyperlipidaemia and cardiovascular disease, and have recently been suggested as a treatment for NAFLD. Aim To review the evidence base for omega-3 fatty acids in NAFLD and critically appraise the literature relating to human trials.

Methods A Medline and PubMed search was performed to identify relevant literature using search terms 'omega-3', 'N-3 PUFA', 'eicosapentaenoic acid', 'docosahexaenoic acid', 'non-alcoholic fatty liver disease' and 'NAFLD'.

Results Omega-3 fatty acids are important regulators of hepatic gene transcription. Animal studies demonstrate they reduce hepatic steatosis, improve insulin sensitivity and reduce markers of inflammation. Clinical trials in human subjects generally confirm these findings but have significant design inadequacies.

Conclusions Omega-3 fatty acids are a promising treatment for NAFLD which require to be tested in randomised placebo controlled trials.