Field notes · The science

Understanding the Omega-3 Index

What EPA and DHA do, what an optimal level looks like, and how to move yours — answers to the questions we get most.
RootCause Health clinical team

What are omega-3s?

Omega-3s are essential fatty acids that support your health. Since the body cannot produce enough omega-3s to meet its needs, they must be obtained through food or supplements.1,2The two most important omega-3s for human health are EPA and DHA, and these are the fatty acids measured by the RootCause Health Omega-3 Index.

Why do omega-3s matter?

Omega-3 fatty acids play important roles throughout the body and are incorporated into cell membranes, where they help support normal cellular function. Research suggests that omega-3s may help regulate inflammatory processes and support cardiovascular, brain, eye, and joint health.

Clinical studies have shown that EPA and DHA can lower triglyceride levels, and certain omega-3 formulations have been associated with a reduced risk of cardiovascular events. Research also suggests that higher omega-3 intake may support cognitive health and may be associated with a lower risk of age-related cognitive decline.

What is the omega-3 index? What is optimal?

The Omega-3 Index measures the percentage of the omega-3 fatty acids EPA and DHA in your red blood cell membranes. Because red blood cells have a lifespan of approximately 120 days, the Omega-3 Index reflects your average omega-3 status over the previous several months rather than your most recent meal or supplement intake.

An Omega-3 Index between 8% and 12% is generally considered optimal. Research has shown that individuals with an Omega-3 Index above 8% have a substantially lower risk of sudden cardiac death compared with those whose Omega-3 Index is below 4%.

The scale

UNDER 4% · HIGHER RISK 8–12% · OPTIMAL

Because red blood cells turn over about every 120 days, your index is a running average — not a snapshot of yesterday's dinner.

How can I increase my level of omega-3s?

The most effective ways to increase your Omega-3 Index are through diet and supplementation. Fatty fish such as salmon, sardines, mackerel, herring, and trout are rich sources of the omega-3 fatty acids EPA and DHA and can help raise your levels over time.

Omega-3 supplements containing EPA and DHA can also increase your Omega-3 Index and may be especially beneficial for individuals who eat little or no fish. Research suggests that achieving an Omega-3 Index of 8% or higher may require approximately two servings of fatty fish per week along with around 1,100 mg of EPA + DHA daily. For individuals who do not consume fish, approximately 1,300 mg of EPA + DHA per day may be required, although individual responses vary.

1,100 mg

EPA + DHA daily, alongside about two servings of fatty fish per week.

1,300 mg

EPA + DHA daily for those who don't eat fish. Individual responses vary.

Many plant-based sources of omega-3s, such as chia seeds, flaxseeds, and walnuts, primarily contain ALA. While ALA is an omega-3 fatty acid, the body's conversion of ALA into EPA is relatively inefficient. For those following a vegetarian or vegan diet, microalgae-derived omega-3 supplements provide EPA and DHA directly and are generally considered the most effective plant-based option for increasing omega-3 status.

How often should I test myself?

Following consistent dietary intervention and daily supplementation, we recommend checking your omega-3 index every 2 months.

References

  1. Calder PC. Mechanisms of action of (n-3) fatty acids. J Nutr. Mar 2012;142(3):592S-599S. doi:10.3945/jn.111.155259
  2. Calder PC. Very long-chain n-3 fatty acids and human health: fact, fiction and the future. Proc Nutr Soc. Feb 2018;77(1):52-72. doi:10.1017/S0029665117003950
  3. von Schacky C. Importance of EPA and DHA Blood Levels in Brain Structure and Function. Nutrients. Mar 25 2021;13(4) doi:10.3390/nu13041074
  4. Hou TY, McMurray DN, Chapkin RS. Omega-3 fatty acids, lipid rafts, and T cell signaling. Eur J Pharmacol. Aug 15 2016;785:2-9. doi:10.1016/j.ejphar.2015.03.091
  5. Bernasconi AA, Wiest MM, Lavie CJ, Milani RV, Laukkanen JA. Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials. Mayo Clin Proc. Feb 2021;96(2):304-313. doi:10.1016/j.mayocp.2020.08.034
  6. Pan M, Zhao F, Xie B, et al. Dietary omega-3 polyunsaturated fatty acids are protective for myopia. Proc Natl Acad Sci U S A. Oct 26 2021;118(43) doi:10.1073/pnas.2104689118
  7. Schonenberger KA, Schupfer AC, Gloy VL, et al. Effect of Anti-Inflammatory Diets on Pain in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis. Nutrients. Nov 24 2021;13(12) doi:10.3390/nu13124221
  8. Mozaffarian D, Maki KC, Bays HE, et al. Effectiveness of a Novel omega-3 Krill Oil Agent in Patients With Severe Hypertriglyceridemia: A Randomized Clinical Trial. JAMA Netw Open. Jan 4 2022;5(1):e2141898. doi:10.1001/jamanetworkopen.2021.41898
  9. Fielding BA. Omega-3 index as a prognosis tool in cardiovascular disease. Curr Opin Clin Nutr Metab Care. Sep 2017;20(5):360-365. doi:10.1097/MCO.0000000000000404
  10. Bianchi VE, Herrera PF, Laura R. Effect of nutrition on neurodegenerative diseases. A systematic review. Nutr Neurosci. Oct 2021;24(10):810-834. doi:10.1080/1028415X.2019.1681088
  11. Smith JA. Exercise, training and red blood cell turnover. Sports Med. Jan 1995;19(1):9-31. doi:10.2165/00007256-199519010-00002
  12. Harris WS. The omega-3 index: clinical utility for therapeutic intervention. Curr Cardiol Rep. Nov 2010;12(6):503-8. doi:10.1007/s11886-010-0141-6
  13. Harris WS, Del Gobbo L, Tintle NL. The Omega-3 Index and relative risk for coronary heart disease mortality: Estimation from 10 cohort studies. Atherosclerosis. Jul 2017;262:51-54. doi:10.1016/j.atherosclerosis.2017.05.007
  14. Carballo-Casla A, Garcia-Esquinas E, Banegas JR, Rodriguez-Artalejo F, Ortola R. Fish consumption, omega-3 fatty acid intake, and risk of pain: the Seniors-ENRICA-1 cohort. Clin Nutr. Nov 2022;41(11):2587-2595. doi:10.1016/j.clnu.2022.09.007
  15. McDonnell SL, French CB, Baggerly CA, Harris WS. Cross-sectional study of the combined associations of dietary and supplemental eicosapentaenoic acid + docosahexaenoic acid on Omega-3 Index. Nutr Res. Nov 2019;71:43-55. doi:10.1016/j.nutres.2019.09.001
  16. Doughman SD, Krupanidhi S, Sanjeevi CB. Omega-3 fatty acids for nutrition and medicine: considering microalgae oil as a vegetarian source of EPA and DHA. Curr Diabetes Rev. Aug 2007;3(3):198-203. doi:10.2174/157339907781368968

One number. One finger-prick.

Find your baseline, adjust your diet or supplement, then re-test in about two months to see it move.

Explore the Omega-3 Index How it works
One number. One finger-prick.