Seal oil, rich in omega-3s, may improve psoriatic arthritis (PsA) patients' global assessment of their disease, suggesting a trend toward a decrease in the number of tender joints, possibly due to seal oil's anti-inflammatory effects, according to a small study in the February issue of the Journal of Rheumatology.1

In the double-blind controlled study, 43 patients with polyarticular PsA received oral treatment for 2 weeks with either seal oil or soy oil. Forty patients (20 in each treatment group) completed the study. Patients were allowed to continue nonsteroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs (DMARDs) during the study.

Patients in the seal oil group reported a significant improvement in global assessment of their disease 4 weeks post-treatment. The seal group also showed a decrease in the ratio of n-6 to n-3 polyunsaturated fatty acids, and in the ratio of arachidonic acid (AA) to eicosapentaenoic acid (EPA) in serum (P <.01), whereas the soy group showed a decrease in total and low-density lipoprotein cholesterol and an increase in linoleic acid (LA) and a-linolenic acid (P <.01). Both groups showed a trend toward improvement in tender joint count. Furthermore, 21% of all patients had elevated values of calprotectin in their feces, suggestive of asymptomatic colitis.

After 2 weeks of treatment, however, the new study failed to achieve its primary endpoints of reduced joint pain and patient global assessment of impact on disease.

In an editorial accompanying the study,2 Leslie G. Cleland, MD, and Michael J. James, PhD, of the rheumatology unit at the Royal Adelaide Hospital in Adelaide, Australia, point out that "the benefit/risk profile for long-term use of omega-3-rich marine oils in inflammatory or cardiovascular disease far outweighs that for NSAIDs."

However, they write, "there is a considerable mismatch in their use, with widespread routine prescription of NSAIDs and neglect of fish oils by prescribers."

In a second related editorial,3 Raffale Scarpa, MD, associate professor of rheumatology at the University Federico II in Naples, Italy, and colleagues write that the results of this trial are significant. Further, since over 20% of patients with PsA had high levels of calprotectin in their feces, confirming the occurrence of asymptomatic colitis, they suugest that it may not be "clinically meaningful" to consider psoriasis and PsA as two distinct clinical diseases. Rather, the authors propose that physicians consider the presence of "psoriatic disease" in order to more effectively diagnose and treat patients with seemingly disparate symptoms.

References

  1. Madland TM, Bjorkkjaer T, Brunborg, A, et al. Subjective improvements in patients with psoriatic arthritis after short-term treatment with seal oil. A pilot study with double-blind comparison to soy oil. J Rheum. 2006;33:307-10.
  2. Cleland LG, James MJ. Marine oils for anti-inflammatory effect – time to take stock. J Rheum. 2006;33:207-209.
  3. Scarpa R, Ayala F, Caporaso, N, et al. Psoriasis, psoriatic arthritis, or psoriatic disease? J Rheum. 2006;33:210-212.