Essential fat

Essential fatty acids (EFAs) are those that the human body needs to function (not meaning energy) but cannot synthesize them from other sources. Therefore, they must be consumed as a part of diet. These are the shortest (18-carbon) ω-3 and ω-6 chains, which have a double bond between the 9th and 10th carbon (counted from the start, not from the ω end).
Essential fatty acids (also SC-PUFA, short chain PUFAs – shortest though having 18 carbons) are:

  • alpha-linolenic acid (ALA): ω-3 fatty acid (best sources: ground / crushed flaxseed, flaxseed oil, chia seeds)
  • linoleic acid (LA): ω-6 fatty acid (sources: various nuts, seeds including flax, and their oils – but avoid too high intake, see also ω-3:ω-6 ratio

The name of both acids is derived from the name of flax (lat. linon).
From these EFAs, the organism can already create (by chain extension and desaturation) another ω-3 and ω-6 fatty acids, important for the body (also called LC-PUFA, long chain PUFA – 20 or 22 carbons):

  • eicosapentaenoic acid (EPA): ω-3 (synthesized from ALA / LA, but with only a few% efficiency, so it is advisable to consume in food: fatty sea fish, seafood, and some marine micro-algae – primary source of EPA / DHA in marine animals)
  • arachidonic acid (AA, from lat. arachis ie peanut, although not found there): ω-6 (synthesized from LA via GLA, with even lower efficiency than EPA, so it is advisable to consume as a part of diet: meat, animal fat, eggs, fish, algae)
  • docosahexaenoic acid (DHA): ω-3 (synthesized from EPA / AA, also with minimal efficiency, better to consume in food – same sources as EPA)

In the case of unhealthy diet, the synthesis of these LC-PUFAs is also impaired, and their deficit is even more pronounced. These three LC-PUFAs are therefore also sometimes, in the broader sense, classified as essential or “conditionally” essential FA.


Back: Chemical properties of fats