DHA can produce changes that help reduce liver fat
Non-alcoholic fatty liver disease (NAFLD) is a spectrum of conditions related to fatty liver that increase the risk of chronic metabolic diseases, such as type 2 diabetes. Insulin resistance appears to be crucial to the onset and progress of NAFLD, mainly through adverse changes to the metabolism of glucose, fatty acids and lipoproteins, and the composition of liver fat appears to be an independent predictor for peripheral and hepatic insulin resistance. Triglyceride (TG) retention in the liver is a prerequisite for developing NAFLD, which also involves an increase in fatty acid (FA) flow to the liver, increased FA synthesis in the liver and a reduction in liver FA oxidation.
High doses of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reduce plasma concentrations of TG. And several studies have concluded that omega-3 FAs have the potential to reduce liver fat, as well as improve insulin sensitivity.
With the aim of assessing whether changes in red blood cell DHA (as a marker of changes to DHA in tissues) are associated with alterations to de novo liver lipogenesis and insulin sensitivity, a research team from the universities of Oxford, Southampton and Surrey randomly assigned 16 subjects with NAFLD to receive 4 g of EPA+DHA or placebo daily for 15-18 months. Before and after the intervention period, fasting and non-fasting liver metabolism and insulin sensitivity (hepatic and peripheral) were measured and the subjects were stratified by the change to red blood cell DHA richness (< or ⩾ 2% after the intervention).
Individuals with an increase in red blood cell DHA of ⩾2% showed favourable changes in both hepatic insulin sensitivity (which increased significantly) and hepatic FA metabolism (do novo hepatic lipogenesis dropped and hepatic FA oxidation increased, both significantly). Despite these changes, from which one might expect a reduction in hepatic TG synthesis and storage, the ⩾2% increase was associated with a reduction (26%) of liver fat content, although not statistically significant.
From these data it may be concluded that individuals with NAFLD who increase their red cell DHA by 2% or more show favourable changes in hepatic FA metabolism and insulin sensitivity, which could help reduce the fat content of the liver.
Hodson L, Bhatia L, Scorletti E, et al. Docosahexaenoic acid enrichment in NAFLD is associated with improvements in hepatic metabolism and hepatic insulin sensitivity: a pilot study. Eur J Clin Nutr. 2017 Aug;71(8):973-979. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5474320/