Do dietary supplements of fish oils improve psoriasis?

In theory, a number of skin and systemic diseases with an inflammatory component should be improved by dietary intake of certain polyunsaturated fatty acids, usually of marine origin. The most significant is eicosapentaenoic acid, which may substitute for arachidonic acid in tissue. Inflammation mediators derived from the former compound are much less active biologically, and also can inhibit the chemotactic behavior of leukotrienes derived from arachidonic acid. A number of studies have appeared describing the effects of such dietary manipulation in patients with psoriasis. Some reports credit fish oil ingestion with moderate improvement of the disease, but problems in the design of these studies have led to criticism of the results.