The omega-3 fatty acid nutritional landscape: health benefits and sources

Dietary fatty acids (FA) are increasingly recognized as major biologic regulators and have properties that relate to health outcomes and disease. The longer chain, more bioactive (n-6) (or omega-6) FA and (n-3) (or omega-3) FA share similar elongation and desaturation enzymes in their conversion from the essential (n-6) FA, linoleic acid, and (n-3) FA, α-linolenic acid (ALA). Conversion from these essential FA is very inefficient. However, now for the (n-3) FA series, soy oil can be enriched with (n-3) stearidonic acid (SDA) to allow for much more efficient conversion to longer chain EPA. EPA and the longer chain DHA possess distinct physical and biological properties that generally impart properties to cells and tissue, which underlie their ability to promote health and prevent disease. Although active in a number of areas of human biology, mechanisms of action of EPA and DHA are perhaps best defined in cardiovascular disease. There is concern that to reach the intake recommendations of EPA and DHA, their supply from cold water fish will be insufficient. Gaps in understanding mechanisms of action of (n-3) FA in a number of health and disease areas as well as optimal sources and intake levels for each need to be defined by further research. Because of the inefficient conversion of ALA, the appearance of SDA in enriched soy oil offers a biologically effective and cost effective approach to providing a sustainable plant source for (n-3) FA in the future.