/ 5 June 1998

Pilchards may help arthritis

sufferers

Michael Nurok

Forget the apple – if new research proves correct, it will be a pilchard a day that keeps the doctor away.

Scientists have been looking at the therapeutic properties of omega-three fatty acids, found in fish oil, in the treatment of rheumatoid arthritis.

South Africa’s richest natural source of the substance is hidden inside our own equivalent of Andy Warhol red white and black Campbell’s Soup cans: pilchards.

With this knowledge in mind, Rosi Andrew decided to test the efficacy of pilchard consumption in rheumatoid arthritis for her honours research project at the University of Cape Town.

Rheumatoid arthritis is one of the auto-immune diseases, in which the body’s immune system sets up a process of ongoing inflammation.

Although almost any organ can be affected, most cases involve inflammation of the joints leading to deformity and concomitant disability.

The course of the disease is variable, but only 20% of those affected experience total remission.

For those that are severely affected, there is a lifetime of drug treatment which comes with its own profile of unpleasant side effects.

Understandably, great interest exists in finding treatments which while effective, don’t cause further morbidity. When researchers found that supplementing rheumatoid arthritis patients with fish oil decreased the clinical manifestations of the disease, a new avenue of investigation was opened.

Fish oil is rich in omega-three fatty acid. Two of these fatty acids, Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), have been found to inhibit a series of biochemical steps that lead to the production of substances called ”inflammatory mediators”.

Inflammatory mediators are normally produced in response to infections and other foreign insults to the body. Under such circumstances they comprise an invaluable weapon in the body’s fight against disease.

However, in rheumatoid arthritis and other auto-immune diseases, these inflammatory mediators are released in the absence of an obvious insult to the body, causing ongoing destruction and inflammation.

By inhibiting the release of inflammatory mediators, EPA and DHA are thought to work in much the same way as conventional anti-rheumatic drugs but without their side effects.

A study published in the Annals of Internal Medicine demonstrated that patients supplemented with fish oil developed less joint tenderness than unsupplemented patients. Another study in the Journal of Rheumatology found that patients taking omega-three fatty acids had their requirements for conventional anti-inflammatory drugs diminished by 60%.

According to Joan Huskisson, head of the University of Cape Town’s Department of Nutrition and Dietetics, canned pilchards are one of South Africa’s richest natural sources of omega-three fatty acids.

Under her guidance, Andrew designed a small trial to investigate the impact of weekly pilchard consumption on rheumatoid arthritis.

She clearly demonstrated that participants consuming pilchards had higher EPA and DHA levels than those that didn’t consume the fish.

However, there was no significant impact on the degree of inflammation or clinical severity of the disease.

Andrew suggested that the very small sample size and short period of study might explain these unexpected findings.

There is currently ongoing investigation of omega-three fatty acids, not only in the treatment of rheumatoid arthritis, but also in their use for hypertension, the prevention of emphysema and chronic bronchitis in smokers, and as essential nutrients in foetal development.

Michael Nurok is a doctor at Somerset hospital in Cape Town