Dr. William L. Smith described his findings on April 4 at Experimental Biology 2006 in San Francisco. His presentation was part of the scientific program of the American Society for Biochemistry and Molecular Biology (ASBMB).
Dietary fish oil causes its prostaglandin-lowering effects through three different mechanisms, says Dr. Smith.
First, the much fewer prostaglandins are made from omega 3 fatty acids as compared to the other class of fatty acids in the body, the omega 6 family of fatty acids that originate in the diet from leafy vegetables and other plant sources.
Second, the omega 3 fatty acids compete with omega 6 fatty acids for the same binding site on the COX 1 enzyme that converts the omega 6 fatty acids to prostaglandin (which is why the COX 1 enzyme and its COX 2 cousin are the targets of anti-inflammatory drugs like ibuprofen). The more omega 3 fatty acids present to block the binding sites, the fewer omega 6 fatty acids are able to be converted to prostaglandin.
Third, although omega 3 fatty acids also are converted to prostaglandins, the prostaglandins formed from omega 3 are generally 2 to 50 times less active than those formed from the omega 6 fatty acids from dietary plants.
The biochemical basis of other benefits of dietary fish oil – for example, omega 3 fatty acids' impact on neuronal development and visual acuity -- are probably due to effects on biochemical pathways regulating nerve transmission. Understanding the different pathways through which omega 3 works to convert prostaglandin helps explain why the plant-based omega 6 fatty acids don't simply provide the same benefits. Because of omega 3 fatty acids' known benefits to health, especially cardiovascular health, Dr. Smith's advice is simple: eat more fish.