Omega-3 Index
Summary
- Omega-3 is a type of healthy fat (especially EPA and DHA) that your body cannot make in meaningful amounts, so you mainly get it from fatty fish or algae-based sources.
- The Omega-3 Index is a blood marker that measures EPA + DHA in red blood cells, reflecting longer-term intake (about the last 3–4 months).
- In a pooled analysis of 17 long-term cohort studies (42,466 people; 15,720 deaths; median 16 years), higher blood omega-3 levels were linked to lower all-cause mortality.
- In a 10-cohort estimate, each 1 standard deviation higher Omega-3 Index was linked to lower fatal coronary heart disease risk (HR about 0.85), and moving from 4% to 8% was estimated to reduce fatal CHD risk by about 30%.
Factor description
This factor measures your Omega-3 Index, a blood-based biomarker of omega-3 status. It is the percentage of EPA + DHA (marine omega-3 fats) in red blood cell membranes, expressed as a percent of total red blood cell fatty acids.
Because red blood cells turn over slowly, the Omega-3 Index reflects longer-term omega-3 intake and correlates with tissue omega-3 status better than short-term blood measures or food questionnaires.
Impact on all-cause mortality
1) Why omega-3 status can influence death risk
- EPA and DHA are part of cell membranes and are linked to pathways that matter for long-term health, especially cardiovascular function and inflammation balance.
- Many deaths in mid-to-late life are driven by cardiovascular and metabolic disease, so factors that support cardiovascular health often show up in all-cause mortality research.
2) What studies typically show
- Across large prospective cohorts, people with higher measured long-chain omega-3 levels (EPA/DHA in blood) tend to have lower all-cause mortality over years of follow-up.
- In a large pooled analysis across 17 cohorts, higher blood omega-3 levels were associated with lower risk of death from any cause.
- In a 10-cohort estimate focused on fatal coronary heart disease, higher Omega-3 Index was linked to lower fatal CHD risk, with a practical improvement estimate when moving from a low level (around 4%) to a higher level (around 8%).
3) Why a blood marker is useful (and often more reliable than diet questionnaires)
- Food questionnaires can be noisy: portion size errors, cooking method differences, and recall bias.
- The Omega-3 Index is a direct biological measure, so it is one of the most accurate ways to assess whether your fish / omega-3 intake is likely sufficient.
Important note on interpretation
- These findings are mostly from observational cohort studies. They show strong associations, but they do not prove omega-3 alone causes longer life in every individual.
- KamaLama uses this factor to help prioritise improvements, not to make deterministic predictions.
Patterns
- Low Omega-3 Index is most common in people who rarely eat fatty fish or avoid seafood (for taste, cost, access, dietary pattern, or cultural reasons).
- People who mostly rely on plant omega-3 (ALA from flax/chia/walnuts) may still have a low Omega-3 Index, because conversion to DHA (and EPA) is limited.
- Fish intake patterns are shaped by availability, price, and local food culture. Public health guidance often recommends fish twice a week, but many people eat less than that.
- Supplements can raise omega-3 status, but they are not risk-free for everyone. People with atrial fibrillation history or on blood-thinning medicines should be cautious and discuss with a clinician.
KamaLama scoring
Scoring logic This factor uses a band-based (threshold + range) approach. There is a meaningful difference between low, middle, and higher Omega-3 Index ranges, and the most practical user action is to move up into the higher target range over time.
Score table
| Category/Range | Score (in years) |
|---|---|
| Omega-3 Index 8% or higher | 0 |
| Omega-3 Index 4–8% | -2 |
| Omega-3 Index below 4% | -5 |
How to read this
- Moving from below 4% to 4–8% is a +3-year improvement on this factor.
- Moving from 4–8% to 8% or higher is a +2-year improvement on this factor.
- Moving from below 4% to 8% or higher is a +5-year improvement on this factor.
Practical tips
- Aim for fatty fish about 2 times per week (for example: salmon, sardines, mackerel, herring, anchovies).
- Choose cooking methods that keep it simple and repeatable: oven-baked, grilled, or canned fish as a quick meal.
- If you do not eat fish, consider algae-based EPA/DHA as an alternative source (especially for vegetarian or vegan diets).
- If you have atrial fibrillation (AF), a history of heart rhythm problems, or you take blood thinners, talk to a clinician before using high-dose omega-3 supplements.
- If you are actively trying to raise your Omega-3 Index, re-test after about 3–4 months (it usually changes over weeks to months, not days).
- Treat omega-3 as one part of longevity nutrition: it works best alongside the basics (whole foods, enough protein, fibre, and less ultra-processed food).
References
Authoritative safety evaluations / guidelines
- NIH Office of Dietary Supplements. Omega-3 Fatty Acids: Health Professional Fact Sheet (updated periodically). https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/ (accessed 27 Dec 2025)
- American Heart Association (2024). Fish and Omega-3 Fatty Acids (recommendation: 2 servings of fish per week). https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fish-and-omega-3-fatty-acids
- Gencer B, et al. (2021). Effect of long-term marine omega-3 supplementation on risk of atrial fibrillation in cardiovascular outcome trials. Circulation. https://pubmed.ncbi.nlm.nih.gov/34612056/
Peer-reviewed / indexed research
- Harris WS, et al. (2021). Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies. Nature Communications. https://www.nature.com/articles/s41467-021-22370-2
- Harris WS, Del Gobbo L, Tintle NL. (2017). The Omega-3 Index and relative risk for coronary heart disease mortality: Estimation from 10 cohort studies. Atherosclerosis. https://pubmed.ncbi.nlm.nih.gov/28511049/
- Harris WS, Del Gobbo L, Tintle NL. (2017). Full text (Atherosclerosis article page). https://www.sciencedirect.com/science/article/abs/pii/S002191501730196X
- Harris WS, von Schacky C. (2004). The Omega-3 Index: a new risk factor for death from coronary heart disease? Preventive Medicine. https://pubmed.ncbi.nlm.nih.gov/15208005/