Stearidonic acid metabolism: Comparison to other dietary omega-3 fatty acids and potential impact on health

The consumption of dietary omega-3 PUFA from marine oils results in their incorporation into cellular membrane phospholipids, and has been associated with health benefits including the modulation of brain and visual development, reduced risk of cardiovascular disease and attenuation of inflammatory reactions. These benefits are largely attributed to the enrichment of tissues with the 20-carbon eicosapentaenoic acid (20:5 n-3; EPA), and the 22-carbon docosapentaenoic acid (22:5 n-3; DPA) and docosahexaenoic acid (22:6 n-3; DHA), and their resulting effects on cellular phenotypes. However, questions related to the sustainability of fish oils has led to the investigation of renewable sources of omega-3 PUFA, largely from agriculture. The 18-carbon alpha-linolenic acid (18:3 n-3; ALA) commonly found in dietary oils including soybean, canola and flaxseed oils has been extensively studied. However, stearidonic acid (18:4 n-3; SDA) is a relatively novel dietary omega-3 PUFA found in dietary oils extracted from the seeds of Bugglossoides arvensis (Ahiflower^TM) and Echium plantagineum oils. This paper will provide an overview of cell culture, animal and human dietary studies investigating the metabolism of SDA. Overall, dietary SDA is significantly more effective than dietary ALA in enriching cells and tissues with 20- and 22-carbon omega-3 PUFA. Recent dietary studies in animal models of inflammatory arthritis will be presented in which dietary B. arvensis oil significantly attenuated disease severity, and impacted on indices of inflammation including cytokine, chemokine, and platelet microvesicle production. Overall, dietary SDA is a more efficient source of renewable omega-3 PUFA than ALA for the enrichment of tissues with long-chain omega-3 PUFA. The study of its potential impact on human disease prevention and/or progression is thus warranted.