Oiling up immunity

When is the last time that you saw a salmon with arthritis? OK, maybe you don’t socialise too frequently with our aquatic brethren (shame on you for not getting out and wet more!), but you may have heard that fish oil has anti-inflammatory effects. This anti-inflammatory action is due to the omega-3 fats EPA and DHA from fish oil, but if fish oil suppresses inflammation does it mean that also suppresses your immune system? According to a new study, that is certainly not the case.

To understand this study, you first have to understand the function of B-cells in your immune system.

B-cells are produced in your bone marrow and are distributed through your body via the lymphatic system. When a foreign substance enters your body, B-cells respond to the foreign proteins by producing specific antibodies. Antibodies are complex proteins that are released into the blood and carried to the site of infection. B-cells do not fight infection directly but produce these antibodies, or immunoglobulins, that are y-shaped protein molecules in response to a particular antigen. Antibodies then interact with the invader and render it harmless.

When an invader tries to invade the body for the first time, each of its proteins activates a B-cell, which divides rapidly to produce a large population of cells. All the new cells are identical: we say they are clones, and they all secrete antibodies specific for the invading pathogen. When the infection is over, most of the newly made B-cells die. However, so that the body can respond more quickly next time, some of the activated B-cells persist in the body for several years. These memory cells “remember” what the invader is like and, if it tries to invade again, they all divide rapidly to produce an even greater number of active B-cells, all capable of secreting specific antibodies.

With that background on B-cells in mind, researchers used two groups of mice for this study. One group was given a standard diet and the other was fed a diet supplemented with DHA-rich fish oil for five weeks. Analysis showed that the fish oil diet led to increased B-cell activation and antibody production. The effect of this would be to improve clearance of any invaders.

If you needed another reason to add some oily fish to your menu once or twice a week, then your B-cells may have just provided it for you.