Omega-3 Index

Longevity, and Mortality Risk

What is the Omega-3 Index and why it matters

The Omega-3 Index measures the percentage of two key omega-3 fatty acids—EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)—in red blood cell membranes.
These long-chain fats, found mainly in fish and algae, are essential for heart, brain, and immune function.
A higher Omega-3 Index reflects long-term omega-3 intake and is a strong marker of cardiovascular and overall health.

Low omega-3 status is linked to inflammation, arrhythmia, and shorter life expectancy, while higher levels (>8%) predict longevity comparable to or better than non-smoking and optimal cholesterol control. [1] [2] [3] [4] [5]

How omega-3 gets into the body

Sources: Fatty fish (salmon, sardines, mackerel), seafood, algae oils, and fortified foods
Conversion: Plant omega-3 (ALA, from flax or chia) converts poorly (<10%) to EPA/DHA
Testing: The Omega-3 Index test measures EPA + DHA in red blood cells and reflects intake over ~3 months.
How often to test: Once or twice a year if supplementing or changing diet

Omega-3 Index Ranges and Mortality Risk

Omega-3 Index (%)	Risk Category	Relative Risk of Mortality	Notes	Sources
<4	High	Reference (highest risk)	Strongly associated with inflammation and cardiovascular death	[1] [2] [3] [4]
4–8	Intermediate	~15–30% lower	Average Western population level	[1] [2] [3] [4]
>8	Low	~30–35% lower	Optimal zone for longevity and heart protection	[1] [2] [3] [4]

Figure 1: Omega-3 Index ranges and mortality risk

Key Research Findings

Each 1 SD increase in Omega-3 Index corresponds to roughly a 15–16% reduction in all-cause mortality. [6] [1] [3]
Individuals with Omega-3 Index >8% have about one-third lower total mortality than those <4%. [1] [2] [3] [4]
Low Omega-3 Index (<4%) doubles 1-year mortality in post–heart attack patients compared with higher levels. [7]
Increasing the Omega-3 Index from 4% to 8% could reduce fatal coronary heart disease risk by around 30%, roughly equivalent to quitting smoking in impact. [2] [3] [4]

Broader Disease Links

Higher Omega-3 Index is linked to lower all-cause, cardiovascular, and non-cardiovascular mortality. [6] [1] [8] [3]
Consistent benefits appear across populations with diabetes, chronic kidney disease, osteoporosis, and cardiovascular disease. [9] [10] [11] [12]
Omega-3 levels also correlate with lower inflammatory markers (CRP, IL-6) and improved heart rate variability.

Practical Guidance

Aim for an Omega-3 Index between 8–11% for optimal protection.
Achieve this by eating fatty fish 2–3 times a week or taking 1–2 grams/day of EPA+DHA supplements.
Plant-based individuals may use algae-derived DHA/EPA supplements for equivalent results.
Retest after 3–4 months to confirm improvement.

Conclusion

Higher Omega-3 Index levels are strongly associated with lower all-cause mortality and longer life expectancy.
Maintaining an Omega-3 Index above 8% can significantly reduce the risk of cardiovascular death and support healthy aging.
The effect size is comparable to other top lifestyle factors such as quitting smoking or maintaining healthy blood pressure.

Disclaimer: This article is for informational purposes only and not a substitute for medical advice.
Scientific summaries were compiled and synthesised using the AI models and peer-reviewed research.

References

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