Omega-3 index: the missing blood value for heart and recovery

The omega-3 index measures the percentage of EPA and DHA in your red blood cells and is a useful marker for your heart and recovery status. Most people in Western Europe sit lower than desirable, often without knowing it. It is one of the simplest deficiencies to measure and address.

I think the omega-3 index is an underrated value, precisely because it links so directly to your diet. You can visibly improve it within a few months.

What is the omega-3 index?

The omega-3 index expresses the share of EPA and DHA as a percentage of all fatty acids in your red blood cell membranes. Because red blood cells last weeks, the index reflects your intake over a longer period, not your last fish meal. A low index counts as an unfavourable cardiovascular risk factor (von Schacky, 2007).

You measure it with the omega-3 index marker.

Why does your omega-3 index matter?

A higher omega-3 index is associated with a lower risk of death from heart disease. An analysis of ten cohorts found that people with a high index had clearly less risk than people with a low index (Harris, 2017). EPA and DHA also play a role in reducing inflammation and in recovery.

Does fish oil or oily fish help?

Both oily fish and supplements can raise your index, though the effect on hard outcomes is nuanced. Meta-analyses of supplements show mixed but mostly modest benefits on cardiovascular disease (Hu, 2019). For your index itself, regular oily fish such as salmon or mackerel, or an EPA/DHA supplement, works.

The nice part is that you can measure the effect: test, adjust your intake, and test again after a few months.

How to test and improve your omega-3 index

Test your index as a baseline, then adjust your intake and follow the trend. A repeat measurement after three to four months shows whether your approach works, because that is how long it takes for your cell membranes to shift. If you wish, combine it with your ApoB for a broader heart picture.

To measure your omega-3 index, compose a panel through our custom blood test. See also ApoB and the overview measuring metabolic health.

My advice: do not guess at your omega-3 status, measure it. A low index is one of the easiest things to improve on purpose, and you see it back in your next measurement.

References

1. Harris WS, Del Gobbo L, Tintle NL. The omega-3 index and relative risk for coronary heart disease mortality: estimation from 10 cohort studies. Atherosclerosis. 2017. PMID: 28511049.
2. Hu Y, Hu FB, Manson JE. Marine omega-3 supplementation and cardiovascular disease: an updated meta-analysis of 13 randomized controlled trials. Journal of the American Heart Association. 2019. PMID: 31567003.
3. von Schacky C. Cardiovascular risk and the omega-3 index. Journal of Cardiovascular Medicine. 2007. PMID: 17876200.

Disclaimer

Every blood test result includes a professional assessment by a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. A blood test is a tool to walk into the conversation with your GP better informed, not a diagnosis in itself. For treatment decisions, discuss your results with your GP.