title: The essentiality of arachidonic acid and docosahexaenoic acid.
abstract: OBJECTIVE
  The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids.
  
  
  BACKGROUND
  Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice.
  
  
  METHODS
  Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA>0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD.
  
  
  RESULTS
  No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when 13% of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model.
  
  
  CONCLUSIONS
  When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to prevent EFAD. Furthermore, AA and DHA alone may be the true EFAs.
authors.affiliation: Department of Surgery, Children's Hospital Boston, Harvard Medical School, 300 Longwood Ave, Fegan 3, Boston, MA 02115, USA.
authors.forename: Hau D
authors.initials: HD
authors.lastname: Le
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Meisel
authors.forename: Vincent E
authors.initials: VE
authors.lastname: de Meijer
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Gura
authors.forename: Mark
authors.initials: M
authors.lastname: Puder
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000008:administration & dosage*; D004281:Docosahexaenoic Acids / Q000008:administration & dosage*; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage; D005228:Fatty Acids, Essential / Q000172:deficiency*; D005395:Fish Oils / Q000627:therapeutic use; D006801:Humans; D010288:Parenteral Nutrition / Q000009:adverse effects / Q000379:methods
chemical_list: D005217:Fat Emulsions, Intravenous; D005228:Fatty Acids, Essential; D005395:Fish Oils; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D015118:Eicosapentaenoic Acid