The Omega-3 Index as a Risk Factor for Coronary Heart Disease

Background

Dr. William S. Harris published this follow-up review in the American Journal of Clinical Nutrition (PMID: 18541601), further establishing the Omega-3 Index as a clinically useful risk factor for coronary heart disease.

Study Design

Review of evidence supporting the Omega-3 Index as a modifiable risk factor, including analytical standardization, population data, and clinical utility assessment.

Key Findings

Analytical validation:

• •Coefficient of variation: <5% (excellent reproducibility)
• •Stability: RBCs reflect ~120-day intake
• •Reference range: Established across populations

Population distribution:

Region	Mean Omega-3 Index
USA	4-5%
UK	4-5%
Germany	5-6%
Korea	8-9%
Japan	9-11%

Regions with higher indices have lower cardiovascular mortality.

Modifiability:

• •Fish intake: +0.5% per serving/week
• •Fish oil supplements: +1-2% with 1 g EPA+DHA/day
• •Response time: 4-6 months to plateau

Mechanistic Insights

The Omega-3 Index reflects cardiac membrane composition:

• •RBC and cardiac tissue levels correlate strongly
• •Membrane omega-3 affects ion channel function
• •Determines arrhythmia susceptibility

Clinical Implications

The Omega-3 Index meets criteria for a useful risk factor:

1. •Biologically plausible mechanism
2. •Graded relationship with outcomes
3. •Modifiable with predictable response
4. •Measurable with standardized assay

Metabolic Health Perspective

Testing the Omega-3 Index removes guesswork from omega-3 status assessment. Unlike dietary recall, it objectively measures tissue levels. Target of ≥8% is achievable and associated with meaningful cardiovascular protection.