Omega-9 fatty acids (ω−9 fatty acids or n−9 fatty acids) are a family of unsaturated fatty acids which have in common a final carbon–carbon double bond in the omega−9 position; that is, the ninth bond from the methyl end of the fatty acid.
Unlike omega-3 fatty acids and omega-6 fatty acids, omega−9 fatty acids are not classed as essential fatty acids (EFA). This is both because they can be created by the human body from unsaturated fat, and are therefore not essential in the diet, and because the lack of an omega−6 double bond keeps them from participating in the reactions that form the eicosanoids.
Some omega−9 fatty acids are common components of animal fat and vegetable oil. Two omega−9 fatty acids important in industry are:
Under severe conditions of EFA deprivation, mammals will elongate and desaturate oleic acid to make Mead acid, (20:3, n−9).[1] This has been documented to a lesser extent in one study following vegetarians and semi-vegetarians who followed diets without substantial sources of EFA.[2]
| hypogeic acid | 16:1 (n−9) | (Z)-hexadec-7-enoic acid | |
| oleic acid | 18:1 (n−9) | (Z)-octadec-9-enoic acid | |
| elaidic acid | 18:1 (n−9) | (E)-octadec-9-enoic acid | |
| gondoic acid | 20:1 (n−9) | (Z)-eicos-11-enoic acid | |
| Mead acid | 20:3 (n−9) | (5Z,8Z,11Z)-eicosa-5,8,11-trienoic acid | |
| erucic acid | 22:1 (n−9) | (Z)-docos-13-enoic acid | |
| nervonic acid | 24:1 (n−9) | (Z)-tetracos-15-enoic acid | |
| ximenic acid | 26:1 (n−9) |