Treatment of Bronchial Asthma With Borage and Echium Seed Oils

Leukotrienes are important in the pathogenesis of inflammation, and leukotriene modifying drugs are now an established treatment for bronchial asthma and rhinitis. Drugs that inhibit the biosynthesis of leukotrienes are likely to be more effective than the currently available drugs that antagonize a single leukotriene receptor. Dietary supplementation with gamma linolenic acid (GLA) in borage seed oil provides effective inhibition of leukotriene generation but also increases circulating free arachidonic acid (AA), which has pro-inflammatory potential. The n-3 fatty acid, eicosapentaenoic acid (EPA), prevented the conversion of GLA to AA. However, EPA is extracted from fish oil, is not well-tolerated due to its taste, and at higher doses appeared to blunt the inhibition of leukotriene biosynthesis by GLA. Stearidonic acid (SDA) is a precursor of EPA that is extracted from Echium plantagineum; it is converted to EPA in humans and it does not have the organoleptic properties of EPA. We recently completed a dose-ranging study in which we determined the dose of SDA that is sufficient to inhibit the rise in circulating levels of arachidonic acid while maintaining effective inhibition of leukotriene generation. The goal of the present study is to test the efficacy of dietary supplementation with GLA and SDA (provided in borage seed oil and echium seed oil) in treating bronchial asthma.