New research throws light on the mechanism by which omega 3 fatty acids specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are really effective in decreasing chronic inflammation and insulin resistance. This study is published in the advance online edition of the September 3 issue of the journal Cell. Jerrold Olefsky and his colleagues of the San Diego School of Medicine, found a key receptor on macrophages abundantly found in obese body fat. These macrophages secreting cytokines and other proteins are the cause of inflammation. This can lead to chronic inflammation and rising insulin resistance in neighbouring cells over-exposed to cytokines. 

    The researchers focused on G-protein receptor called GPR120, which are present only on pro-inflammatory macrophages in mature fat cells. When the receptor is turned off, the macrophage produces inflammatory effects. But exposed to omega-3 fatty acids, the GPR120 receptor is activated and generates a strong anti-inflammatory effect. Dr. Jerrold Olefsky, and his team conducted the study on cell cultures and mice to assess how cellular receptors respond to fatty acids. They fed mice, some of which genetically engineered to lack the GPR120 receptors with high-fat diet, in the presence and absence of omega-3 fatty acid supplementation. They noticed that the supplementation of omega-3 inhibited the inflammation and enhanced insulin sensitivity in the obese mice, while it has no effect in the GPR120 eliminated mice.