Several studies have shown that supplementation with n-3 polyunsaturated fatty acids (n-3 PUFAs) found in fish oils is beneficial for rheumatoid arthritis (RA) patients. Spanish medical researchers now report that RA patients tend to have decreased levels of n-3 PUFAs in their blood and synovial (joint) fluid. Their study involved 24 female and 15 male RA patients (median age of 64 years). Blood and joint fluid samples were collected from the patients and from a control group consisting of 28 healthy volunteers (17 male and 11 female with a median age of 61 years). All samples were analyzed to determine their fatty acid profile.

RA patients were found to have significantly lower levels of eicosapentaenoic acid (the main component of fish tissue oil) in both their blood plasma and synovial fluid. The level of alpha-linolenic acid was lower in the synovial fluid of RA patients, but not in their blood plasma. The level of docosahexaenoic acid (a major component of fish tissue oil) also tended to be lower in synovial fluids of RA patients, but not in their blood plasma.

The researchers conclude that RA patients have an abnormal fatty acid profile and a significant deficiency in certain essential fatty acids. They believe this finding may explain why supplements such as fish oils and gamma-linolenic acid (from evening primrose and borage) have been found to be beneficial in the treatment of rheumatoid arthritis