Designer oils’ low in n-6:n-3 fatty acid ratio beneficially modifies cardiovascular risks in mice.

Key Findings:

The current dietary n-6:n-3 FA ratio is anywhere from 10:1 to 30:1 instead of a recommended 2:1 to 4:1. A ‘designer oil’ developed using flaxseed oil and with a 2:1 ratio was compared to fish oil or a safflower oil with a high (25:1) n-6:n-3 FA ratio was fed to mice as part of an atherogenic diet. The flax and fish groups showed a significant reduction in plasma TG at week 4, as compared to baseline data. Conversion of ALA to EPA/DHA was supported by the finding of lower n-6:n-3 FA ratios and higher EPA/DHA concentrations in heart of the flax group (compared to control). Increased cardiac tissue EPA and DHA as a result of ALA feeding was observed. Significantly higher steatosis was found in the control group compared to both fish and flax groups. The flaxseed based designer oil did not increase heart tissue EPA and DHA to levels similar to the fish group.

ABSTRACT:

Cardiovascular benefits of dietary n-3 fatty acids have been shown. However, benefits of n-3 fatty acids as part of a high fat, low n-6:n-3 fatty acid ratio diet has not been fully characterized. Aim of this study is to investigate cardiovascular and metabolic benefits of ‘designer oils’ containing a low ratio of n-6:n-3 fatty acids in C57BL/6 mice. Three groups of C57BL/6 mice were fed an atherogenic diet supplemented with either a fish oil- or flaxseed oil-based ‘designer oil’ with an approximate n-6:n-3 fatty acid ratio of 2:1 (treated groups, n = 6 each) or with a safflower oil-based formulation with a high ratio (25:1) of n-6:n-3 fatty acids (control group, n = 6) for 6 weeks. Food intake, body weight, and blood lipid levels were monitored regularly. Fatty acid profile of the heart tissues was assessed. Histological assessment of liver samples was conducted. At the end of the study body weight and food intake was significantly higher in the flax group compared to control. The levels of 20:5n-3 and 22:6n-3 was significantly increased in the heart phospholipids in both flax and fish groups compared to control; tissue 20:4n-6 was significantly reduced in the fish group compared to control. Significant liver pathology was observed in the control group only. Lowering dietary ratio of n-6:n-3 fatty acids may significantly reduce cardiovascular and metabolic risks in mice regardless of the source of n-3 fatty acids. (Author’s abstract)