Polyunsaturated fatty acids (PUFA) contain the parent essential fatty acids, linoleic acid LA (Omega 6 Fatty Acids) and a-linolenic acid ALNA (Omega 3 Fatty Acids) and their longchain more unsaturated derivatives. The parent essential fatty acids LA and ALNA cannot be manufactured in humans and therefore they need to be consumed as part of the daily diet. They are converted into their desaturated derivatives as indicated. Both Omega 6 and 3 fatty acids have common enzymes in their metabolic pathway; Omega 3 fatty acids fatty acids usually have higher affinity for the enzymes than the Omega 6 fatty acids. The rate limiting enzymes in the desaturation process is the A-6 desaturase. This enzyme is under the control of many dietary and hormonal factors.
The most significant PUFA of the Omega 6 fatty acids series are dihomogammalinoleic acid (DHGLA) and arachidonic acid (AA) and these are the precursors of the eicosanoids of `1’ and `2’ series respectively. The important PUFA of the Omega 3 fatty acids series are eicosopentanoic acid (EPA) and docosahexaenoic acid (DHA). EPA (to which DHA can be reconverted) is the precursor of the eicosanoids of `3’ series. Furthermore, “Diets high in polyunsaturated fat have been more effective than low-fat, high-carbohydrate diets in lowering cholesterol as well as the incidence of heart disease.” New England Journal of Medicine, 337:1491-1499.
Eicosanoids derived from these precursors are highly active compounds. The eicosanoids cascade consists of; cyclic products generated by cyclooxygenase – such as prostaglandins, prostacyclin and thromboxane, lipoxygenase products such as leukotrienes and products of cytocrane P400 activity. The wide-ranging functions of the eicosanoids. AA (of the Omega 6 fatty acids series) and EPA (of the Omega 3 fatty acids series) compete for the same enzymes, cyclo-oxygenase and lipoxygenases for conversion to eicosanoids (prostaglandins thromboxanes and leukotrienes). Eicosanoids derived from AA and from EPA have opposing metabolic properties. Therefore it is important to ensure a balanced dietary intake of Omega 6 and 3 fatty acids PUFAs.
Mike Maunu – Founder
Oxygen4Life.com
