Sustainable Production of Omega-3 Fatty Acids

Abstract

Omega-3 fatty acids represent essential nutrients for animals and humans. The most common plant-derived precursor for the bioactive long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is alpha-linolenic acid (ALA). ALA is the only omega-3 fatty acid available in vegetable oils that are produced in substantial volumes. However, conversion of ALA to EPA and DHA is inefficient in humans due to a metabolic bottleneck represented by the Δ6-desaturase enzyme that converts ALA to stearidonic acid (SDA), the first intermediate in the metabolic pathway that converts ALA to EPA and DHA. SDA is present in small amounts in the oil of some herbs such as borage oil or hemp oil; however, these oils are not available in large quantities. Compared to the main vegetable oils that contain ALA, a more efficient source for long-chain omega-3 fatty acids is provided by marine cold water fish that contain substantial amounts of EPA and DHA in membrane and storage lipids. These fish do not have the metabolic capacity to synthesize omega-3 fatty acids from central intermediates of their metabolism themselves. Instead they acquire EPA and DHA through their food chain that is founded on marine algae as primary producers. Unfortunately the human consumption of fish is limited by an increasingly finite supply of marine stocks, by encumbrance of some marine fish with environmental toxins, and by dietary preferences in the Western cultures that tend to avoid fish as food source. This chapter reviews the discovery and relevance of omega-3 fatty acids as an essential human nutrient, the limitations of the marine ecosystem in providing the bioactive omega-3 fatty acids EPA and DHA in sufficient quantities for human consumption, and the development of SDA soybeans that are soybeans with substantially improved omega-3 profile. SDA soybeans contain 20 % of their total fatty acids as SDA. As such, they represent a much more efficient source of omega-3 fatty acids than traditional vegetable oils that contain ALA only. SDA soybean oil has been shown to perform similar as conventional soybean when incorporated into human foods. In contrast to specialty oils, production of SDA soybean oil is more economical and can easily be ramped up to produce large quantities. In contrast to marine omega-3 sources SDA soybean oil is free of environmental toxins and not tied to the volume limitations of the marine ecosystem. This positions SDA soybean oil as an environmentally friendly sustainable source of essential omega-3 fatty acids for the increasing demand of a growing human population.