Standardizing methods for assessing omega-3 fatty acid biostatus

The Omega-3 Index is the sum of EPA+DHA in RBC membranes expressed as a percent of total fatty acids. Typical levels range from 3% to 9%, with a US average value of between 5%-6%. The Index is a marker of tissue EPA+DHA and therefore reflects an individual's EPA+DHA status. The Omega-3 Index fulfills most of the criteria for a valid biomarker. In routine clinical practice, the Omega-3 Index can be used to assess baseline n-3 fatty acid status and to check for compliance with a recommendation to increase the n-3 fatty acid intake. In the research setting, the Omega-3 Index can likewise document compliance, both to confirm that those assigned to the n-3 fatty acid group followed instructions and that those assigned to placebo did not take n-3 fatty acid off protocol. In addition, the Omega-3 Index can be used as an inclusion criterion in trial design to confirm that only individuals most likely to benefit from n-3 fatty acid treatment are included. The widespread clinical implementation of the Omega-3 Index will allow clinicians to detect n-3 "insufficiency", to better stratify patients with respect to risk for disease, and it could ultimately contribute to a reduced burden of chronic disease.