Long-chain polyunsaturated fatty acids and the pathophysiology of myalgic encephalomyelitis (chronic fatigue syndrome).

Evidence is put forward to suggest that myalgic encephalomyelitis, also known as chronic fatigue syndrome, may be associated with persistent viral infection. In turn, such infections are likely to impair the ability of the body to biosynthesise n-3 and n-6 long-chain polyunsaturated fatty acids by inhibiting the delta-6 desaturation of the precursor essential fatty acids--namely, alpha-linolenic acid and linoleic acid. This would, in turn, impair the proper functioning of cell membranes, including cell signalling, and have an adverse effect on the biosynthesis of eicosanoids from the long-chain polyunsaturated fatty acids dihomo-gamma-linolenic acid, arachidonic acid and eicosapentaenoic acid. These actions might offer an explanation for some of the symptoms and signs of myalgic encephalomyelitis. A potential therapeutic avenue could be offered by bypassing the inhibition of the enzyme delta-6-desaturase by treatment with virgin cold-pressed non-raffinated evening primrose oil, which would supply gamma-linolenic acid and lipophilic pentacyclic triterpenes, and with eicosapentaenoic acid. The gamma-linolenic acid can readily be converted into dihomo-gamma-linolenic acid and thence arachidonic acid, while triterpenes have important free radical scavenging, cyclo-oxygenase and neutrophil elastase inhibitory activities. Furthermore, both arachidonic acid and eicosapentaenoic acid are, at relatively low concentrations, directly virucidal.