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 (DHA, 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. Design 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 thirteen percent 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.

Effect of nutrients on total lipid content and fatty acids profile of Scenedesmus obliquus

“…Among them, polyunsaturated fatty acids (PUFAs) especially eicosapentaenoic (EPA), docosahexaenoic (DHA), and arachidonic acids (AA) are the most valuable to create significant physiological and biochemical changes in a body, including reducing risk of cardiovascular diseases [5][6][7][8][9] . Definitely, the total lipid content may vary noticeably among individual species or strains within and between taxonomic groups 7 .…”

PUFAs: Structures, Metabolism and Functions

“…Moreover, a high concentration of eicosatrienoic acid, which normally occurs in trace amounts, indicates deficiency of substrates for the synthesis of omega-3 and omega-6 series of polyunsaturated fatty acids; this value might thus have a diagnostic importance. The same enzymes participate in conversion of fatty acids of all three series, showing functional connections between metabolic paths of omega-3, -6 and -9 acids, which depend on competing for enzymes and regulating a given stage of transformation based on a negative feedback through a direct or indirect product [3,4,6].…”

“…Eicosapentaenoic acid (EPA, C20 : 5ω-3) is metabolized in a similar way with the participation of the same enzymes, i.e. cyclooxygenase and lipoxygenase, however its metabolic products are different: 3-series prostanoids and 5-series leukotrienes of different properties mostly antiinflammatory (PGE 3 , LTA 5 , LTB 5 , LTC 5 , LTD 5 ), antiaggregatory (TXA 3 ) and vasodilative (PGI 3 ) [3,[6][7][8] …”

Inhibition of neuroblastoma cell proliferation with omega-3 fatty acids and treatment of a murine model of human neuroblastoma using a diet enriched with omega-3 fatty acids in combination with sunitinib

“…Because prolonged administration of high levels of ω-3 FAs in children is safe (24,25), we propose that ω-3 FAs may be effective in the combination treatment of neuroblastoma.…”