The main physiological requirement for ω-6 fatty acids is attributed to arachidonic acid. Arachidonic acid is the major precursor of prostaglandins, leukotrienes that play a vital role in cell signaling, and an endogenous cannabinoid anandamide. Metabolites from the ω-3 pathway, mainly from eicosapentaenoic acid, are mostly inactive, and this explains why ω-3 fatty acids do not correct the reproductive failure in rats where arachidonic is needed to make active prostaglandins that cause uterine contraction. To some extent, any ω-3 or ω-6 can contribute to the growth-promoting effects of EFA deficiency, but only ω-6 fatty acids can restore reproductive performance and correct the dermatitis in rats. Particular fatty acids are still needed at critical life stages (e.g. lactation) and in some disease states. In nonscientific writing, common usage is that the term essential fatty acid comprises all the ω-3 or -6 fatty acids. Conjugated fatty acids like calendic acid are not considered essential. Authoritative sources include the whole families, but generally only make dietary recommendations for LA and ALA with the exception of DHA for infants under the age of 6 months. Recent reviews by WHO/FAO in 2009 and the European Food Safety Authority have reviewed the evidence and made recommendations for minimal intakes of LA and ALA and have also recommended intakes of longer chain ω-3 fatty acids based on the association of oily fish consumption with a lower risk of cardiovascular disease.
Microvenular hemangioma  is an acquired benign vascular tumor that presents as an asymptomatic, slowly growing, 0.5- to 2.0 cm reddish lesion on the forearms or other sites of young to middle-aged adults. See also
List of cutaneous conditions

References


== External links ==