Effects of duration of treatment and dosage of eicosapentaenoic acid and stearidonic acid on red blood cell eicosapentaenoic acid content

Objective: The purpose of this randomized, controlled, parallel group study was to characterize the relationships between dosages of stearidonic acid (SDA) and eicosapentaenoic acid (EPA), and incorporation of EPA into red blood cell (RBC) membranes over time. Methods: Healthy subjects (n = 131) received capsules with placebo (safflower oil), SDA (0.43, 1.3, 2.6, or 5.2 g/d) or EPA (0.44, 1.3, or 2.7 g/d) for 12 weeks. RBC fatty acids were analyzed biweekly. Results: RBC %EPA increased in all EPA and SDA groups (p < 0.02 vs. control) except the 0.43 g/d SDA group (p = 0.187). For theoretical intakes of EPA of 0.25, 0.5, and 0.89 g/d, the amounts of SDA needed to achieve equivalent RBC EPA enrichment were 0.61, 1.89, and 5.32 g/d (conversion efficiencies of 41%, 26%, and 17%), respectively. Conclusions: SDA increased RBC %EPA in a dosage and time-dependent manner at intakes as low as 1.3 g/d. (C) 2011 Elsevier Ltd. All rights reserved.