Fw: RA & Seafood

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Contact: Dr Sperling

508 824 3872

British Society of Immunology

Seafood On The Menu For Rheumatoid Arthritis Sufferers

We have long been advised to reduce the amount of saturated fat in our

diets and to make sure that we eat polyunsaturates instead. But now it

seems that the type of polyunsaturated fat could also be important, if

you suffer from an inflammatory disease like rheumatoid arthritis (RA).

At the British Society for Immunology Annual Congress in Brighton this

week, Dr Sperling of the Brigham and Women's Hospital, Boston,

USA will describe how altering the type of fat in the diet can alter the

immune system's inflammatory response, with benefits for the patient.

Neutrophils are the most common type of white blood cell. They are found

in large numbers at the site of inflammation in RA and inflammatory

bowel disease. They have a number of pro-inflammatory effects.

Neutrophils make a molecule called leukotriene B4 (LTB4) which plays a

critical role in promoting inflammation. The starting material they use

is a polyunsaturated fatty acid called arachidonic acid, which in turn

is derived from the types of polyunsaturated fatty acids found in

land-based plants and animals.

Marine plants and animals contain quite different fatty acids from their

land-based equivalents, for example eicosapentaenoic acid and

docosahexaenoic acid. These fatty acids can take the place of

arachidonic acid in the neutrophil's LTB4 manufacturing process,

resulting in slightly different end products. These products have a less

inflammatory effect than LTB4 itself.

Dr Sperling and his colleagues have shown that dietary eicosapentaenoic

acid reduces the production of LTB4 by neutrophils, both from healthy

donors and patients with inflammatory disorders.

In addition, a diet rich in eicosapentaenoic acid and other

marine-derived fatty acids has been shown to have other beneficial

effects on neutrophil activity: neutrophils are less likely to migrate

to the site of inflammation, and to release other molecules and enzymes

which cause damage at the site of inflammation.

A number of studies have shown that diets enriched in marine fish oils

have a modest beneficial effect in patients with diseases such as RA and

inflammatory bowel disease. Dr Sperling's results suggest that this is

because of the calming effect these oils have on neutrophil activity.