Omega-3 Fatty Acids

Why It Matters for Longevity

EPA and DHA support cell membrane fluidity, reduce systemic inflammation, lower triglycerides by 15–30%, and improve endothelial function. DHA is the predominant fatty acid in neuronal membranes and is inversely associated with cognitive decline and Alzheimer's disease risk in prospective cohort studies.

The VITAL trial — a landmark RCT of 25,871 adults followed for 5.3 years — found that marine omega-3 supplementation (1 g/day EPA+DHA) significantly reduced the risk of myocardial infarction by 28% overall, with a 50% reduction in heart attack risk in those with low dietary fish intake. The trial confirmed cardiovascular protection from omega-3s in a primary prevention population (Manson et al., 2019, N Engl J Med).

A large meta-analysis of 38 RCTs involving 149,051 participants found that omega-3 supplementation reduced cardiovascular mortality by 7% (RR 0.93, 95% CI 0.88–0.98), non-fatal myocardial infarction by 13% (RR 0.87), and coronary heart disease events by 9% (RR 0.91). EPA monotherapy showed superior risk reductions compared to EPA+DHA combinations across most endpoints, though at the cost of increased atrial fibrillation risk (RR 1.26) (Khan et al., 2021, EClinicalMedicine).

A dose-response meta-analysis of 40 RCTs (135,267 participants) found that the protective effect on fatal MI (RR 0.65, 95% CI 0.46–0.91) and coronary heart disease events (RR 0.90) increases with higher EPA+DHA dose, supporting the Longevity Diet's emphasis on obtaining omega-3s from multiple sources rather than minimal supplementation alone (Bernasconi et al., 2021, Mayo Clin Proc).

The REDUCE-IT trial (8,179 patients with hypertriglyceridemia on statins, followed 4.9 years) demonstrated that high-dose icosapentaenoic acid — pure EPA at 4 g/day — reduced major adverse cardiovascular events by 25% (HR 0.75, 95% CI 0.68–0.83) and cardiovascular death, MI, and stroke by 26% (HR 0.74) compared to placebo. This is the largest EPA-specific cardiovascular outcome trial and demonstrates that the molecule responsible for benefit is EPA's direct anti-inflammatory and membrane-stabilizing actions rather than triglyceride lowering alone (Bhatt et al., 2019, N Engl J Med).

A meta-analysis of 10 prospective cohort studies (310,955 participants, mean follow-up 8.7 years) found that high circulating omega-3 levels (EPA + DHA + DPA in serum/plasma phospholipid) were associated with a 45% lower risk of sudden cardiac death and cardiovascular mortality (HR 0.55, 95% CI 0.37–0.82). EPA alone in red blood cell membranes — a measure of long-term intake known as the omega-3 index — was associated with 21% lower risk (HR 0.79, 95% CI 0.60–0.82), and DHA alone with 28% lower risk (Kim et al., 2025, J Clin Med). These biomarker data reinforce the value of the omega-3 index (EPA + DHA as a percentage of total red blood cell fatty acids) as a predictor of cardiovascular risk; a target of ≥8% is considered cardioprotective in observational studies, while most Western populations average 4–5%.

EPA and DHA exert multiple anti-inflammatory mechanisms: they compete with arachidonic acid for cyclooxygenase enzymes, generate specialized pro-resolving mediators (resolvins, protectins, maresins), and suppress NF-κB-driven cytokine production. These mechanisms underlie the reduction in cardiovascular events, protection against arrhythmia, and the associations with reduced inflammatory disease risk documented in the literature (Calder, 2017, Biochem Soc Trans).

The plant-derived ALA (from walnuts, flaxseed, canola oil) has independent cardioprotective effects, though conversion to EPA/DHA is inefficient (~5–10% to EPA, <0.5% to DHA). The Longevity Diet's emphasis on fatty fish 2–3 times per week is designed to provide preformed EPA and DHA while plant sources contribute ALA to the total omega-3 intake.

The Omega-3 Index as a Biomarker

The omega-3 index — defined as EPA + DHA expressed as a percentage of total fatty acids in red blood cell membranes — integrates dietary intake and individual metabolism over the preceding 4–6 weeks. An index below 4% is associated with substantially elevated cardiovascular risk; 8% or above is the target range based on observational data. The index can be measured via dried blood spot tests. Achieving the upper range typically requires either consistent fatty fish consumption (3+ servings per week) or supplementation with approximately 2–3 g EPA+DHA daily on top of modest dietary intake. The biomarker is increasingly used in clinical trials as a more accurate measure of omega-3 status than dietary recall.

How to Use It

Obtain EPA/DHA from fatty fish (sardines, anchovies, salmon) 2–3 times per week per the Longevity Diet protocol. Supplement with omega-3 fish oil (1–2 g EPA+DHA/day) if dietary fish intake is limited. Obtain ALA from walnuts (~2.5 g per 30 g serving), ground flaxseed (~2.4 g per tablespoon), and canola oil (~1.3 g per tablespoon). If pursuing therapeutic cardiovascular benefit, high-dose EPA supplementation (prescription icosapentaenoic acid, 4 g/day) should be discussed with a physician given the atrial fibrillation signal.

What to Pair It With

Flavor Profile

Neutral as supplement, fishy from fish oil, mild-to-nutty from plant sources (flaxseed oil, walnuts). Oily and liquid at room temperature. Category: nutrient / functional fat.

The Science

• Manson et al., 2019, N Engl J Med: VITAL trial — omega-3 supplementation (1 g/day) reduced myocardial infarction risk by 28% overall, 50% in those with low dietary fish intake, over 5.3 years in a primary prevention population.
• Calder, 2017, Biochem Soc Trans: Review of omega-3 anti-inflammatory mechanisms — EPA and DHA suppress NF-κB signaling, generate specialized pro-resolving mediators, and reduce inflammatory cytokine production, explaining their broad protective effects.
• Khan et al., 2021, EClinicalMedicine: Meta-analysis of 38 RCTs (149,051 participants) — omega-3 supplementation reduced cardiovascular mortality by 7%, non-fatal MI by 13%, and coronary heart disease events by 9%; EPA monotherapy outperformed EPA+DHA combinations.
• Bernasconi et al., 2021, Mayo Clin Proc: Dose-response meta-analysis of 40 RCTs (135,267 participants) — protective effect on fatal MI (RR 0.65) and CHD events increases with EPA+DHA dose, supporting higher-intake protocols.
• Bhatt et al., 2019, N Engl J Med: REDUCE-IT trial — high-dose EPA (icosapentaenoic acid, 4 g/day) reduced major adverse cardiovascular events by 25% (HR 0.75) in high-risk patients with hypertriglyceridemia on statins over 4.9 years.
• Kim et al., 2025, J Clin Med: Meta-analysis of 10 cohort studies (310,955 participants) — high circulating omega-3 (EPA+DHA+DPA) associated with 45% lower risk of sudden cardiac death; omega-3 index in red blood cell membranes inversely associated with cardiovascular mortality.

References

1. Manson JE, Cook NR, Lee IM, et al. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med. 2019;380(1):23-32. PMID: 30415637. doi:10.1056/NEJMoa1811403
2. Calder PC. Omega-3 fatty acids and inflammatory processes: from molecules to man. Biochem Soc Trans. 2017;45(5):1105-1115. PMID: 28900017. doi:10.1042/BST20160474
3. Khan SU, Lone AN, Khan MS, et al. Effect of omega-3 fatty acids on cardiovascular outcomes: A systematic review and meta-analysis. EClinicalMedicine. 2021;38:100997. PMID: 34505026. doi:10.1016/j.eclinm.2021.100997
4. 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. 2021;96(2):304-313. PMID: 32951855. doi:10.1016/j.mayocp.2020.08.034
5. Bhatt DL, Steg PG, Miller M, et al. Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia. N Engl J Med. 2019;380(1):11-22. PMID: 30415628. doi:10.1056/NEJMoa1812792
6. Kim JY, Kong SYJ, Jung E, Cho YS. Omega-3 Fatty Acids as Potential Predictors of Sudden Cardiac Death and Cardiovascular Mortality: A Systematic Review and Meta-Analysis. J Clin Med. 2025;14(2):343. PMID: 39797109. doi:10.3390/jcm14020343

Key Nutrients