Table 1.
Fatty acid (FA) classification and nomenclature
| SCFAA | C1 | C2 | C3 | C4 | C5 | Synthetic |
|---|---|---|---|---|---|---|
| Formic acid | Acetic acid | Propionic acid | Butyric acid | Valeric acid | Valproic acid (VPA) |
| MCFA | C6 | C8 | C10 | C12 |
|---|---|---|---|---|
| Caproic acid | Caprylic acid | Capric acid | Lauric acid |
| LCFA | C16 | C18 | C20 | C22 |
|---|---|---|---|---|
| SFAB |
Palmitic acid C16:0 |
Stearic acid C18:0 |
Arachidic acid C20:0 |
Behenic acid C22:0 |
| MUFA |
Palmitoleic acid C16:1 |
Oleic acid C18:1 |
Gondoic acid C20:1 |
Erucic acid C22:1 |
| Omega-6 PUFA |
Linoleic acid C18:2 (LNA) |
Dihomo-γ-linoleic acid C20:3 |
Docosapenaenoic acid C22:5 |
|
|
γ-linoleic acid C18:3 |
Arachidonic acid C20:4 (ARA) |
|||
| Omega-3 PUFA |
α-linoleic acid C18:3 (ALA) |
Eicosatetranoic acid C20:4 (EPA) |
Docosahexanoic acid C22:6 (DHA) |
|
|
Stearidonic acid C18:4 |
Dicosapentaenioc acid C20:5 |
A: FAs are categorized according to the length of the carbon chain, and the number, position of double bonds. Short-chain fatty acids (SCFAs) refer to those that contain 1–5 carbon atoms, while medium-chain fatty acids (MCFAs) are those of 6–12, and long-chain fatty acids (LCFAs) of 14–22, very-long-chain fatty acids (VLCFA) of > 24. B: The number of double bonds decides whether they are saturated (SFAs), or mono-/poly-unsaturated fatty acids (M/PUFAs)
LCFA long-chain fatty acid, MCFA medium-chain fatty acid, MUFA mono-unsaturated fatty acid, PUFA poly-unsaturated fatty acid, SCFA short-chain fatty acid, SFA saturated fatty acid