ABSTRACT
The conversion of parent EFA to LC-PUFA greater than 18carbon chain length is under active regulation. Factors influencing desaturase activities may be classified into nutritional, hormonal, genetic, and physiologic factors such as age. These factors are not independent and, in some cases, the effects of nutritional factors are likely to be explained by a modification of hormonal status (16). The effect of AA, EPA, and DHA cannot be reproduced by substituting equivalent amounts of LA or ALA. Excess dietary LA associated with some vegetable oils may decrease the formation of DHA from ALA because the 6desaturase is inhibited by excess substrate. In addition, AA formation is lower when excess LA is provided (2,7,17-19).
