Stearidonic acid (SDA: C<sub>18</sub>H<sub>28</sub>O<sub>2</sub>; 18:4, n-3) is an ÃÂ-3 fatty acid, sometimes called moroctic acid.
It is biosynthesized from alpha-linolenic acid (ALA: C<sub>18</sub>H<sub>30</sub>O<sub>2</sub>; 18:3, n-3) by the enzyme delta-6-desaturase, which removes two hydrogen (H) atoms.
Stearidonic acid is involved in the synthesis of longer-chain ÃÂ-3 fatty acids in animals (including humans), plants, and bacteria. It is a precursor to eicosapentaenoic acid via a eicosatetraenoic acid (20:4 ÃÂ-3) intermediate. Studies in humans volunteers and cell cultures suggest that SDA increases EPA levels more efficiently than an equimolar amount of ALA.
SDA is also a precursor to N-acylethanolamine (NAEs).
Natural sources of this fatty acid are the seed oils of hemp, blackcurrant, Buglossoides arvensis (corn gromwell), and Echium plantagineum, and the cyanobacterium Spirulina.
As it is a precursor to other fatty acids, there has been efforts to enhance the content off stearidonic acid in various crops, such as soybeans. A GMO soybean source is approved by the European Food Safety Authority.
SDA can also be synthesized in a lab.