Study unveils mechanism behind the fish oil effect

29 October 2009

A study has revealed why fish oils help alleviate inflammatory conditions such as rheumatoid arthritis, which could lead to new treatments for other diseases.

"We have known for some time that fish oils can help with conditions like arthritis which are linked to inflammation," said Mauro Perretti, Professor of Immunopharmacology at Queen Mary, University of London, who led the research alongside colleagues from Harvard Medical School in the USA.

"What we've shown here is how the body processes a particular ingredient of fish oils into the chemical Resolvin D2. This seems to be a very powerful chemical and a small amount can have a large effect."

The researchers found that our bodies convert docosahexaenoic acid (DHA) - an omega-3 fatty acid found in fish oils - into Resolvin D2, which helps reduce inflammation.

Previous research has shown that a crucial step in inflammation - which occurs when the body's own immune system mistakenly targets healthy tissue - is when white blood cells stick to the inner lining of the blood vessels, called the endothelium.

In laboratory studies, the researchers found that Resolvin D2 causes the endothelial cells to produce small amounts of nitric oxide. This acts as a chemical signal discouraging the white blood cells from sticking to the endothelial cells and preventing inflammation.

"This research explains at least one way in which fish oils can help in different types of arthritis," said Professor Perretti.

"We can also work on this chemical and see if it can be used not only to treat or even prevent arthritis, but also as a possible treatment for a variety of other diseases associated with inflammation."

The researchers suggest that Resolvin D2 could form the basis of new treatments for other diseases, including sepsis and stroke. Unlike other anti-inflammatory drugs, the chemical does not appear to suppress the immune system.

The research was funded by the Arthritis Research Campaign, the National Institutes of Health and the Wellcome Trust.

Image: Omega 3 fish oil capsules spilling out of bottle. Credit: Libby Welch, Wellcome Images

Reference

Spite et al. Resolvin D2 is a potent regulator of leukocytes and controls microbial sepsis. Nature 2009