Within the fields of academic biology, medicine and nutrition the adjective ‘essential’ is used in three different ways:

• the common usage of '‘must have’ or ‘cannot do without’ this or that substance if one wants to achieve good health. Many fatty acids are deemed 'essential ' or 'singly essential' in this sense, including the 'derivative' fatty acids (see 'Essential and 'derivative' fatty acids')
  
• as a shorthand for 'this substance cannot be made by the human body'. There are two fatty acids considered 'doubly essential' - omega-3 alpha-linolenic acid (ALA) and omega-6 linoleic acid (LA) - in that:
  
  • we cannot do without them if we want to achieve good health
    
  • they cannot be made by the human body so have to be obtained from foods
    
• as a synonym of the adjective 'pristine', meaning 'in its original state', 'undamaged', 'untainted', 'undiminished'. If one wanted to only use the most whole, clean, vibrant nutrients one would seek out those that:
  
  • have been grown organically (to both maximise nutrient levels and minimise toxic chemical pesticide and fertiliser residues) and
    
  • are raw (uncooked) and 'raw' (i.e. have not been exposed to temperatures exceeding 49 degrees Centigrade/120 degrees Fahrenheit during processing in order to minimise damage to nutrient levels)

If one wanted to emphasise the importance of using only the most vibrant, cleanest, least damaged 'doubly essential' fatty acids one might refer to these as 'triply essential'. Many nutrients carefully extracted from organically-grown plants and non-human animals may justifiably be described 'triply essential' including, as we see above, the two fatty acids LA and ALA.

(17637) Nick Anderson. Green Health Watch Magazine 27.7.2019