EPA and DHA can lower tissue levels of arachidonic acid and replace it in cell membrane. This might be explained by the ability of omega-3 fatty acids to inhibit platelets. Omega-3 fatty acids are also considered anti-thrombotic at very high doses, potentially increasing the bleeding time ( 20). Omega-3 fatty acids also decrease resting systolic and diastolic blood pressure by incorporation of EPA and DHA into membrane phospholipids and therefore increasing systemic arterial compliance ( 19). Omega-3 fatty acids may also lead to improved endothelial function by promoting the release of nitric oxide from endothelial cells ( 19).
In a trial of 20 healthy athletes, daily supplementation with 3.6 grams of omega-3 fatty acids for 6 weeks did not alter cytokine response to strenuous exercise nor did it change the blood concentrations of neutrophils and lymphocytes ( 18). The study showed some anti-inflammatory effects for DHA, but none for EPA ( 17). In a rat model of spinal cord injury, EPA and DHA administration could not reverse the hepatic inflammatory response induced by laminectomy or spinal cord injury. Some studies, however, have questioned the effect of omega-3 fatty acids on inflammation. It has been hypothesized that such anti-inflammatory properties may reduce vascular atherogenic inflammation ( 15). Omega-3 fatty acids also modify the production of eicosanoids (such as reducing the levels of thromboxane A 2 and leukotriene B 4) thereby leading to reduced inflammation. Furthermore, omega-3 fatty acids suppress the acute phase reactants ( 16). The rapid modulation of transcription can directly impact the inflammatory pathways.
They also bind to specific nuclear receptors and transcription factors such as PPAR-α, HNF-4α and SREBP-1c that regulate gene expression ( 15). Some animal studies show that omega-3 fatty acids can suppress the production of interleukin-2 and inhibit lipopolysaccharide-induced inflammation ( 15). Omega-3 fatty acids exert anti-inflammatory properties through different mechanisms. Also, the integration of omega-3 fatty acids into cell membrane in animal studies resulted in changes in H-Ras signaling protein and suppressed protein kinase C-theta signaling ( 15). Membrane-incorporated omega-3 fatty acids might be able to alter membrane protein signaling. Animal studies show that adding omega-3 fatty acids to cell membrane can alter cellular function by interaction with and modulation of membrane channels and proteins thereby changing the physiochemical properties of cell membrane.
The composition of lipids in the cell membrane affects multiple cellular functions. Molecular and Cellular Effects of Omega-3 Fatty Acids