Fatty Acids [Glossary]

Fats are made from fatty acids (FAs); generally they are put into three major groups, but each group has many different types of that type with it. The main groups are saturated, monounsaturated and polyunsaturated fatty acids; here more about the FAs in each one.

Fatty acids are made from chains of carbon atoms with attached hydrogen and oxygen atoms. The length of the carbon ‘backbone’ and the number of unsaturated bonds determines which fatty acid we end up with.

Saturated fatty acids (all available bonds used up) are more stable than monounsaturated FAs (one bond available) which in turn are more stable than polyunaturated FAs (which have two or more spare bonds). The more spare bonds, the more ‘bendy’ or fluid the fatty acid.

All fats and oils contain different proportions of saturated, monounsaturated and polyunsaturated fats; those with more of the former tend to be solid at room temperature and those with more of the latter tend to be liquid.

Below are the common names used. (Read more about dietary fats and their properties here.)

Saturated fatty acids

These include (smallest to largest):

• butyric acid
• caproic acid
• caprylic acid
• capric acid
• lauric acid
• myristic acid
• palmitic acid
• stearic acid
• arachidic acid
• behenic acid
• lignoceric acid

Monunsaturated fatty acids

These include (smallest to largest):

• myristoleic acid
• palmitoleic acid
• oleic acid
• gadoleic acid
• erucic acid
• nervonic acid

Polyunsaturated fatty acids

These include (smallest to largest):

• linoleic acid
• linolenic acid
• alpha-linolenic acid (ALA – see picture)
• gamma-linolenic acid
• arachidonic acid
• timnodonic acid or EPA*
• brassic acid
• clupanodonic acid
• DHA**

*eicosapentaenoic acid – an essential omega-3 fatty acid

**docosahexaenoic acid – an essential omega-3 fatty acid