The GPR120 receptor is found only on pro-inflammatory macrophages in mature fat cells. When the receptor is turned off, the macrophage produces inflammation. Unchecked inflammation has been linked to insulin resistance, diabetes, cancer, osteoporosis and heart disease. When exposed to omega-3 fatty acids, specifically those found in fish oil, the GPR120 receptor is activated resulting in broad anti-inflammatory effects and improved systemic insulin sensitivity.
Source: journal Cell, 9-2-2010