Omega-6 fatty acids and inflammation

  • Jacqueline K. Innes
    Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, IDS Building, MP887 Southampton General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom
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  • Philip C. Calder
    Corresponding author at: Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, IDS Building, MP887 Southampton General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom.
    Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, IDS Building, MP887 Southampton General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom

    National Institute for Health Research Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton SO16 6YD, United Kingdom
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      • There is a high content of omega-6 PUFAs, particularly arachidonic acid, in membranes of cells involved in inflammation.
      • High omega-6 PUFA dietary intake has been linked to inflammation, mainly because ARA is the precursor of pro-inflammatory lipid mediators.
      • However, some studies have shown that increased dietary intake of omega-6 PUFAs may not lead to enhanced inflammation.
      • This article investigates the extent to which omega-6 PUFAs are involved in the inflammatory process.


      Inflammation is a normal process that is part of host defence and tissue healing. However, excessive or unresolved inflammation can lead to uncontrolled tissue damage, pathology and disease. In humans on a Western diet, the omega-6 polyunsaturated fatty acid arachidonic acid (ARA) makes a significant contribution to the fatty acids present in the membrane phospholipids of cells involved in inflammation. ARA is a precursor to a number of potent pro-inflammatory mediators including well described prostaglandins and leukotrienes, which has led to the development of anti-inflammatory pharmaceuticals that target the ARA pathway to successfully control inflammation. Hence, it is commonly believed that increasing dietary intake of the omega-6 fatty acids ARA or its precursor linoleic acid (LA) will increase inflammation. However, studies in healthy human adults have found that increased intake of ARA or LA does not increase the concentrations of many inflammatory markers. Epidemiological studies have even suggested that ARA and LA may be linked to reduced inflammation. Contrastingly, there is also evidence that a high omega-6 fatty acid diet inhibits the anti-inflammatory and inflammation-resolving effect of the omega-3 fatty acids. Thus, the interaction of omega-3 and omega-6 fatty acids and their lipid mediators in the context of inflammation is complex and still not properly understood.



      ARA (arachidonic acid), ARASCO (arachidonic acid-rich single-cell oil), COX (cyclooxygenase), CRP (C-reactive protein), DGLA (dihomo-gamma-linolenic acid), DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid), GLA (gamma-linolenic acid), HETE (hydroxyeicosatetraenoic acid), HODE (hydroxyoctadecadienoic acid), IL (interleukin), LA (linoleic acid), LOX (lipoxygenase), LPS (lipopolysaccharide), LT (leukotriene), LXA4 (lipoxin A4), NF-kB (nuclear factor kappa B), PBMC (peripheral blood mononuclear cell), PG (prostaglandin), PMN (polymorphonuclear neutrophil), PPAR (peroxisome proliferator-activated receptor), PUFA (polyunsaturated fatty acid), sE-selectin (soluble E-selectin), sICAM-1 (soluble intercellular adhesion molecule 1), sTNF-R1 (soluble tumour necrosis factor receptor-1), sVCAM-1 (soluble vascular cell adhesion molecule 1), TGF-β (transforming growth factor β), TNF (tumour necrosis factor), TX (thromboxane)
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