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The Omega-6:Omega-3 ratio: A critical appraisal and possible successor

  • William S. Harris
    Correspondence
    Corresponding author at: OmegaQuant Analytics, LLC, 5009 W. 12th St, Ste 8, Sioux Falls, SD 57106, United States.
    Affiliations
    OmegaQuant Analytics, LLC and Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, United States
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      Highlights

      • Polyunsaturated fatty acid blood levels have predictive power for disease outcomes.
      • Both the Omega-3 Index and the n6:n3 ratio have been used to express PUFA status.
      • The n6:n3 ratio has become scientifically out-dated.
      • The Omega-3 Index, because if included EPA and DHA only, is a preferred metric.

      Abstract

      The well-known health effects of the long-chain, marine omega-3 (n-3) fatty acids (FAs) has led to a growing interest in the prognostic value that blood levels of these FAs might have vis-à-vis cardiovascular and neurocognitive diseases. The measurement and expression of n-3 FA levels is not straight-forward, however, and a wide variety of means of expression of n-3 FA status have been used in research and clinical medicine. This has led to considerable confusion as to what “optimal” n-3 FA status is. The n-6:n-3 ratio has enjoyed relatively widespread use, but this apparently simple metric has both theoretical and practical difficulties that have contributed to misunderstandings in this field. Just as the once-popular polyunsaturated:saturated FA ratio has largely disappeared from the nutritional and medical literature, it may be time to replace the n-6:n-3 ratio with a newer metric that focuses on the primary deficiency in Western diets – the lack of eicosapentaenoic and docosahexaenoic acids (EPA and DHA). The Omega-3 Index (red blood cell EPA+DHA) has much to recommend it in this regard.

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