A lot has been made recently of omega-3 fatty acids or alpha linolenic acid in the treatment of inflammatory dermatoses or atopic dermatitis and the appropriate balance of omega-3s with omega-6 fatty acids. However, not much is known about the underlying mechanisms by the average layperson or indeed the industry as a whole. What actually happens is that when a cellular injury occurs, the cell membranes release their fatty acids and are then metabolized into substances known as eicosanoids, which are compounds such as prostaglandins, leukotrienes, thromboxanes, etc. ("eico" is Greek for 20, indicating that they are a metabolite of 20 carbon atom fatty acids such as arachidonic acid and eicosapentanoic acid).
First, omega-6 fatty acids (linoleic acid) are metabolized into gamma-linolenic acid by the enzyme delta-6-desaturase, then into di-homo gamma-linolenic acid by the enzyme elongase, then finally into arachidonic acid by the enzyme delta 5-desaturase. Omega-3 fatty acids (alpha linolenic acid) are also first metabolized into stearidonic acid by the enzyme delta-6-desaturase, then into eicosatetraenoic acid by the enzyme elongase, and finally into eicosapentaenoic acid (EPA) by the enzyme delta-5-desaturase.
Eicosanoids produced from arachidonic acid such as leukotriene B4 are more inflammatory than eicosanoids produced from eicosapentanoic acid such as leukotriene B5. EPA and arachidonic acid compete for the same enzymes, however, and when the level of EPA is increased, the production of the more inflammatory B4 eicosanoids is decreased and the production of less inflammatory B5 eicosanoids is increased. However, some dogs and most cats have a deficiency of delta-6-desaturase enzyme activity in their skin, which is why the addition of supplements high in omega-3s do not necessarily help. For cats and some dogs, the addition of supplements with EPA are indicated.
This is why we use wild salmon oil in our Wild Salmon Oil(tm) Supplement. It supplies DHA and EPA directly without the need for conversion as well as other important factors.