Omega-3 fatty acids are among the most researched nutrients in nutritional science, with evidence spanning cardiovascular health, brain function, joint health, inflammation, and mental health. Yet most Westerners are significantly deficient. Here’s the complete picture.
EPA and DHA: The Critical Forms
The body can convert plant-based ALA (from flaxseed, chia, walnuts) to EPA and DHA, but at very low rates — under 10% for EPA, under 1% for DHA. Direct consumption of EPA and DHA from marine sources is essential for meaningful benefit.
The Omega-6 to Omega-3 Ratio Problem
The modern diet has an omega-6 to omega-3 ratio of 15:1 to 20:1. We evolved at roughly 4:1. Excess omega-6 from vegetable oils and processed foods promotes inflammation. Correcting this ratio by increasing omega-3 is one of the most impactful nutritional interventions available.
Evidence-Based Benefits
Cardiovascular: Reduces triglycerides, lowers blood pressure, reduces arterial inflammation. High-dose EPA (Vascepa) has FDA approval for cardiovascular event reduction.
Brain health: DHA makes up ~15% of fatty acids in the brain’s cerebral cortex. Higher omega-3 status is linked to larger brain volume, better cognition, and reduced Alzheimer’s risk.
Mental health: EPA-dominant omega-3 at 1–2g/day shows meaningful antidepressant effects in multiple meta-analyses. See: The Gut-Brain Connection.
Joint health: EPA and DHA are precursors to anti-inflammatory resolvins and protectins, reducing joint stiffness in rheumatoid arthritis.
Best Food Sources
- Wild salmon: 1,500–2,500mg EPA+DHA per 3 oz
- Mackerel: 1,000–2,000mg per 3 oz
- Sardines: 1,000–1,500mg per 3 oz
- Herring: 900–1,700mg per 3 oz
Should You Supplement?
If you eat fatty fish 2–3 times weekly, you may be adequate. Otherwise, 1–2g combined EPA+DHA from fish oil, krill oil, or algae oil (for vegans/vegetarians) is a strong choice. Look for third-party tested products for heavy metals and oxidation.
The Bottom Line
Omega-3 deficiency affects every major body system. Eat more fatty fish, or supplement. This single change delivers broad health returns.