Daily Consumption of α-Linolenic Acid Increases Conversion Efficiency to Eicosapentaenoic Acid in Mice

To maintain a beneficial concentration of eicosapentaenoic acid (EPA), the efficient conversion
of its precursor, α-linolenic acid (α-LA), is important. Here, we studied the conversion of α-LA to
EPA using ICR and C57BL/6 mice. A single dose of perilla oil rich-in α-LA or free α-LA had not
been converted to EPA 18 h following administration. The α-LA was absorbed into the
circulation, and its concentration peaked 6 h after administration, after which it rapidly
decreased. In contrast, EPA administration was followed by an increase in circulating EPA
concentration, but this did not decrease between 6 and 18 h, indicating that the clearance of
EPA is slower than that of α-LA. After ≥1 week perilla oil intake, the circulating EPA
concentration was >20 times higher than that of the control group which consumed olive oil,
indicating that daily consumption, but not a single dose, of α-LA-rich oil might help preserve the
physiologic EPA concentration. The consumption of high concentrations of perilla oil for 4 weeks
also increased the hepatic expression of Elovl5, which is involved in fatty acid elongation;
however, further studies are needed to characterize the relationship between the expression of
this gene and the conversion of α-LA to EPA.