The conversion of dihomo-gamma-linolenic acid (DGLA) to ARA is regulated by insulin and ARA/EPA ratio is a sensitive marker for insulin resistance, a common denominator of most chronic inflammatory diseases. In a study of healthy adult volunteers AA to EPA ratio and the ARA precursor – DGLA, significantly changed with age (Tsoukalas et al., 2019a). The metabolism of n-6 PUFAs is more prevalent compared with n-3 PUFA, due to the fact that LA is much more common in actual diets (Blasbalg et al., 2011), although ALA, and not LA, is the preferred substrate for Δ6-desaturase (Calder, 2015).