Research: Anti-Inflammatory Effects of Omega-3 Fatty Acid in Fish Oil

Omega-3 fatty acids in dietary fish oil are reported to have anti-inflammatory and anti-thrombogenic and anti-arrhythmic effects in humans, but the biochemical basis for these beneficial health effects is not well understood. Now a University of Michigan biochemist reports that fish oil significantly diminishes the production and effectiveness of various prostaglandins, naturally occurring hormone-like substances that can accentuate inflammation and thrombosis.

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.