Omega-6 fatty acids predominate in vegetable oils, including soybean oil. Omega-3 fatty acids, on the other hand, are concentrated in cold-water fatty fish. Some experts believe that excessive consumption of omega-6 fatty acids is inflammatory, contributing to chronic diseases of civilization.
The usual U.S. omega-6/omega-3 fatty acid diet ratio is 15:1. The study at hand altered that to 4:1. That is, they reduced omega-6 or increased omega-3 fatty acid consumption over 12 weeks.
I’ve written about fatty liver disease many times (use search box in interested). The worst outcome is chronic inflammation leading to cirrhosis.
The study at hand suggests that reducing dietary omega-6 fatty acids and increasing omega-3s can help reverse fat build-up in the liver, at least in obese adolescents.
From a poster presentation published by the American Diabetes Association:
Recent literature suggests that the dietary imbalance between high omega-6 (n6) and low omega-3 (n3) polyunsaturated fatty acids (PUFA) intake, characteristic of the Western diet (average ratio 15:1), leads to development of fatty liver disease. We aimed to determine whether 12 weeks of a low n6/n3 PUFA ratio (4:1) normo-caloric diet might impact fatty liver (MRI assessed hepatic fat content ≥5.5%). Twenty obese adolescents with fatty liver were recruited (13.2±2.9y). Abdominal MRI and OGTT were performed at baseline and after 12-weeks intervention, the oxidized derivatives of linoleic acid (OXLAM) were measured every 4 weeks to assess compliance. Food was supplied to participants isocaloric to their pre-study diet. To control for weight change variable, weight was maintained stable throughout the study. Seventeen adolescents completed the study. After 12 weeks HFF%, decreased of about 26% (Figure 1). There was also a significant decrease in plasma concentrations of ALT (Figure 1), triglycerides (p=0.04) cholesterol (p=0.03), LDL (p=0.07) and an improvement of whole-body insulin resistance (p=0.01). There was a significant decrease of the OXLAM, 9- and 13-HODE (p=0.03 and p=0.01, respectively) and 9- and 13-oxo-ODE (p=0.05 and p=0.01, respectively). These data suggest that, independent of weight loss, a low n6/n3 PUFA diet is effective to ameliorate the metabolic phenotype of adolescents with fatty liver disease.
Steve Parker, M.D.
PS: The Mediterranean diet traditionally is low in omega-6 and rich with omega-3 fatty acids.