Metabolism of stearidonic acid in human subjects: comparison with the metabolism of other n−3 fatty acids

Abstract

Background: For many persons who wish to obtain the health benefits provided by dietary n−3 fatty acids, daily ingestion of fish or fish oil is not a sustainable long-term approach. To increase the number of sustainable dietary options, a land-based source of n−3 fatty acids that is effective in increasing tissue concentrations of the long-chain n−3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is required. Objective: The objective of the study was to examine the ability of dietary stearidonic acid (SDA) to increase tissue concentrations of EPA and DHA in healthy human subjects and to compare the effectiveness of SDA with that of the n−3 fatty acids α-linolenic acid (ALA) and EPA. Design: Encapsulated SDA, ALA, or EPA was ingested daily in doses of 0.75 g and then 1.5 g for periods of 3 wk each by healthy male and postmenopausal female subjects (n = 15/group) in a double-blind, parallel-group design. Results: Dietary SDA increased EPA and docosapentaenoic acid concentrations but not DHA concentrations in erythrocyte and in plasma phospholipids. The relative effectiveness of the tested dietary fatty acids in increasing tissue EPA was 1:0.3:0.07 for EPA:SDA:ALA. Conclusions: Vegetable oils containing SDA could be a dietary source of n−3 fatty acids that would be more effective in increasing tissue EPA concentrations than are current ALA-containing vegetable oils. The use of SDA-containing oils in food manufacture could provide a wide range of dietary alternatives for increasing tissue EPA concentrations.