Effects of N-3 fatty acids on hepatic triglyceride content in humans

Background: Because dietary N-3 fatty acids reduce plasma triglycerides, they may also decrease hepatic triglyceride content. If so, N-3 fatty acids might constitute a therapy for fatty liver. Methods: Twenty-two subjects were recruited into a study designed to test the effects of N-3 fatty acids on liver fat content. Seventeen completed the trial that had a sequential design of 4-week placebo followed by an 8-week treatment with 9 g/d of fish oil. Liver fat was measured during placebo and treatment by magnetic resonance spectroscopy. Compliance was assessed by capsule count at the end of each study phase and measurement of fatty acid composition in plasma triglyceride and phospholipid. Plasma lipoproteins and adiponectin were also measured. Results: Treatment with fish oils reduced significantly levels of plasma triglyceride by 46% (P <.03), very low-density lipoprotein + intermediate density lipoprotein cholesterol by 21% (P <.03), total apolipoprotein B by 15% (P <.03). In contrast to the changes in plasma triglycerides, hepatic triglyceride content was not significantly reduced by fish oil treatment. Conclusions: N-3 fatty acids at high doses lower plasma triglyceride levels, but there are no significant decreases in hepatic content of triglyceride for the group as a whole. Whereas the triglyceride lowering is uniform, the liver response is more variable.