Scientists have discovered why a diet high in oily fish like salmon and mackerel may help improve inflammatory conditions such as arthritis.
They have found a key anti-inflammatory fat in humans is derived from a fatty acid found in fish oil.
The researchers, from Harvard Medical School and Brigham and Women’s Hospital, found the diet worked best when combined with low aspirin doses.
The inflammatory response protects the body against infection and injury, but when it goes wrong it can lead to conditions such as arthritis, and cardiovascular disease.
The Harvard team identified a new class of fats in the human body, called resolvins, which they showed can control inflammation.
They do this both by stopping the migration of inflammatory cells to sites of inflammation, and the turning on of other inflammatory cells.
Resolvins are made from the omega-3 fatty acids, found in high concentration in oily fish.
Their production also appears to be stimulated by taking aspirin.
One form of resolvin – E1 – is thought to play a particularly significant role in controlling inflammation.
The researchers identified this specific fat in blood plasma samples taken from volunteers given omega-3 fatty acids and aspirin.