--- title: "Evidence: Erythrocyte EPA+DHA percentage" description: "Maintaining an optimal Omega-3 Index (8-11%) is linked to better brain health and should be used to guide EPA and DHA supplementation." url: "https://magellanlongevity.com/study/s143.md" canonical: "https://magellanlongevity.com/study/s143.html" html: "https://magellanlongevity.com/study/s143.html" type: "study" study_key: "s143" journal: "Nutrients" year: 2021 pmid: "33806218" doi: "10.3390/nu13041074" citations: 1 updated: 2026-09-02 author: "Gabriel Radu, DO" author_credentials: "Physiatrist (PM&R). NY medical license 275110. NPI 1376861765." publisher: "Magellan Longevity" content_format: "markdown" --- # Evidence: Erythrocyte EPA+DHA percentage [Home](https://magellanlongevity.com/) › [Research map](https://magellanlongevity.com/longevity-research-map.html) › Evidence: Erythrocyte EPA+DHA percentage **HTML version:** https://magellanlongevity.com/study/s143.html · **In the Magellan app:** https://magellanlongevity.com/#/study/s143 ## Citation | Field | Value | | --- | --- | | Journal | Nutrients | | Year | 2021 | | PMID | [33806218](https://pubmed.ncbi.nlm.nih.gov/33806218/) | | DOI | [10.3390/nu13041074](https://doi.org/10.3390/nu13041074) | | Study key | s143 | ## Takeaway Maintaining an optimal Omega-3 Index (8-11%) is linked to better brain health and should be used to guide EPA and DHA supplementation. ## The question What is the significance of the erythrocyte EPA+DHA percentage (Omega-3 Index) for brain health and how does it relate to the design and interpretation of EPA and DHA intervention trials? ## Hypothesis The abstract implies that an optimal Omega-3 Index is crucial for brain health and that using the Omega-3 Index to guide EPA and DHA interventions could improve trial outcomes and clarify their effects. ## Methods This is a review article summarizing existing evidence regarding the Omega-3 Index, its association with brain health outcomes from epidemiological studies, and its implications for the design and interpretation of EPA and DHA intervention trials. ## Results The Omega-3 Index ranges from 2% to 20%, with an optimal range of 8-11%. A lower Omega-3 Index is associated with increased risks for total mortality, ischemic stroke, reduced brain volume, impaired cognition, accelerated dementia progression, psychiatric diseases, and compromised complex brain functions. Intervention trials often yield neutral results when not considering baseline blood levels, but when trial results are evaluated using measured blood levels of EPA and DHA, effects are larger and align with epidemiological findings. ## Conclusion The Omega-3 Index is a valuable biomarker for assessing EPA and DHA status, reflecting brain health risks, and should be used to guide the design and interpretation of future EPA and DHA intervention trials for more targeted and effective use. ## Limitations The abstract does not explicitly state limitations of the Omega-3 Index itself or the reviewed studies, but it highlights that many intervention trials have produced neutral results due to design flaws (e.g., not considering baseline blood levels). ## Verbatim from the abstract > a lower Omega-3 Index was associated with increased risk for total mortality and ischemic stroke ## Optimal Omega-3 Index Range | Measure | Omega-3 Index (%) | | --- | --- | | Lower Bound | 8 | | Upper Bound | 11 | *The optimal Omega-3 Index, expressed as a percentage of EPA+DHA in erythrocytes, is between 8% and 11%.* ## Where this study is used on Magellan This paper is one of the citations behind the evidence grade on the pages below. Grades are assigned from the published research and are independent of affiliate commissions. | Compound or device | Evidence grade | Graded pages | | --- | --- | --- | | Omega-3 Index Test | Measurement tool | [Omega-3 Index Test](https://magellanlongevity.com/p/143.md) | ## Reference 1. **Evidence: Erythrocyte EPA+DHA percentage** Nutrients 2021 · [PMID 33806218](https://pubmed.ncbi.nlm.nih.gov/33806218/) · [DOI 10.3390/nu13041074](https://doi.org/10.3390/nu13041074) > a lower Omega-3 Index was associated with increased risk for total mortality and ischemic stroke ## Structured data ```json {"@context":"https://schema.org","@graph":[{"@type":"MedicalWebPage","@id":"https://magellanlongevity.com/study/s143.html#page","url":"https://magellanlongevity.com/study/s143.html","name":"Evidence: Erythrocyte EPA+DHA percentage","description":"Maintaining an optimal Omega-3 Index (8-11%) is linked to better brain health and should be used to guide EPA and DHA supplementation.","inLanguage":"en","isPartOf":{"@type":"WebSite","name":"Magellan Longevity","url":"https://magellanlongevity.com/"},"author":{"@type":"Person","name":"Gabriel Radu, DO","jobTitle":"Physiatrist (PM&R)","identifier":[{"@type":"PropertyValue","name":"NPI","value":"1376861765"},{"@type":"PropertyValue","name":"NY medical license","value":"275110"}]},"publisher":{"@type":"Organization","name":"Magellan Longevity","url":"https://magellanlongevity.com/"},"encoding":{"@type":"MediaObject","encodingFormat":"text/markdown","contentUrl":"https://magellanlongevity.com/study/s143.md"},"dateModified":"2026-09-02"},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://magellanlongevity.com/"},{"@type":"ListItem","position":2,"name":"Research map","item":"https://magellanlongevity.com/longevity-research-map.html"},{"@type":"ListItem","position":3,"name":"Evidence: Erythrocyte EPA+DHA percentage","item":"https://magellanlongevity.com/study/s143.html"}]},{"@type":"ScholarlyArticle","@id":"https://magellanlongevity.com/study/s143.html#study","name":"Evidence: Erythrocyte EPA+DHA percentage","headline":"Evidence: Erythrocyte EPA+DHA percentage","datePublished":"2021","isPartOf":{"@type":"Periodical","name":"Nutrients"},"identifier":"PMID:33806218","url":"https://pubmed.ncbi.nlm.nih.gov/33806218/","sameAs":"https://doi.org/10.3390/nu13041074","abstract":"Maintaining an optimal Omega-3 Index (8-11%) is linked to better brain health and should be used to guide EPA and DHA supplementation."}]} ``` ## Related on Magellan Longevity - [Omega-3 Index Test](https://magellanlongevity.com/p/143.md) — product graded on this and related evidence - [Omega-3 fatty acids and mortality in patients referred for coronary angiography](https://magellanlongevity.com/study/d27397734.md) - [Longevity research map](https://magellanlongevity.com/longevity-research-map.html) - [Evidence-based longevity supplements](https://magellanlongevity.com/longevity-supplements.md) ## Scope and disclosures Educational information, not medical advice. Nothing here is intended to diagnose, treat, cure, or prevent any disease. Talk to your physician before starting any supplement or device, especially if you are pregnant, nursing, or taking medication. Editorial firewall: evidence grades are assigned from the published research and are independent of any affiliate commission. As an Amazon Associate, Magellan Longevity earns from qualifying purchases. Reviewed for accuracy by a board-certified physician (DO).