The omega-3 index: From biomarker to risk marker to risk factor

Abstract

Blood levels of omega-3 fatty acids reflect the interplay of metabolism and the intake of omega-3-rich foods (eg, oily fish). Multiple lines of evidence link reduced tissue and/or blood levels of omega-3 fatty acids, as reflected in the erythrocyte eicosapentaenoic acid plus docosahexaenoic acid level (ie, the omega-3 index), with increased risk for coronary heart disease, especially sudden cardiac death. The purpose of this review is to examine the extent to which biomarkers like the omega-3 index qualify as coronary heart disease risk markers and/or risk factors based on new criteria from the American Heart Association and older guidelines proposed in 1965 by Sir Austin Bradford Hill. These standards include consistency, strength of association, biological plausibility, coherence, dose-response relationship, clinical utility, cost effectiveness, and prospective validation. The omega-3 index appears to fulfill many of the requirements for a risk marker and, more importantly, for a risk factor.

Prevention of Cardiovascular Disease by Dietary n-3 Fatty Acid

“…This index reflects the proportion of n-3 PUFA in the membrane of red blood cells, with below 4% indicative of coronary artery disease whereas levels exceeding 8% give the lowest risk of CVD events. It may thus be used to identify individuals requiring n-3 PUFA supplementation and/or dietary modification [26].…”

“…It might be better to consider PUFA individually rather than as a ratio (which does not distinguish between ALA and EPA+DHA) and to provide evidence-based dietary advice to increase n-3 PUFA intake rather than just decreasing n-6 PUFA. Assessment of individual needs may be based on the n-3 red blood cell index [26], but further studies are needed to validate this novel biomarker for cardiovascular risk.…”

Fish Oil Metabolites: Translating Promising Findings from Bench to bedside to Reduce Cardiovascular Disease

“…When considering establishment of a biomarker, it has to be determined whether the measured mediator is a risk factor that is active in a pathway leading to disease, or is a risk marker that is a sign of the disease [27]. This differentiation is very critical for understanding whether alteration of concentrations can improve health.…”

Evaluation of the hepatic bioconversion of α-linolenic acid (ALA) to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in rats fed with oils from chia (<i>Salvia hispánica</i>) or rosa mosqueta (<i>Rosa rubiginosa</i>)

“…Both EPA and DHA are involved in multiple functions in the human body by playing a central role in the physiology and normal development of individuals from their early embrionary life to the elderly (Li and Hu, 2009;Harris, 2009;Picq et al, 2010). Thus, DHA is crucial during fetal and postnatal neurogenesis (Haggarty, 2010), playing an important role in cognitive and visual development (Hoffman et al, 2009).…”