Omega 3s and the Omega 3 Index: Why We Test It

Omega 3 fatty acids are one of the few supplements with enough evidence behind them that I test for them directly. The test is called the Omega 3 Index, and most Americans score poorly on it.

What omega 3s are

EPA and DHA are the two long chain omega 3 fatty acids your body uses most. They are structural components of every cell membrane, concentrated in the brain, eyes, and heart. They also produce signaling molecules that resolve inflammation. Your body makes very little of them, so they come from diet, mostly fatty fish like salmon, sardines, and mackerel.

The standard American diet is low in EPA and DHA and high in omega 6 fats from seed oils, which shifts cell membrane composition away from the pattern seen in populations with the best cardiovascular outcomes.

The Omega 3 Index

The Omega 3 Index measures EPA and DHA as a percentage of the fatty acids in your red blood cell membranes. Because red cells live about 4 months, it reflects your long term intake, not what you ate this week.

• Below 4 percent: the higher risk zone where most Americans sit.
• 4 to 8 percent: intermediate.
• 8 percent and above: the target range, associated in cohort studies with lower cardiovascular risk and roughly the levels seen in Japan, where omega 3 intake is high and heart disease rates are low.

What the evidence supports

The honest summary: omega 3s modestly lower triglycerides in a dose dependent way, and high dose purified EPA reduced cardiovascular events in a major trial of high risk adults. Population studies consistently associate a higher index with lower cardiovascular and all cause mortality. Trials in the general population have been mixed, partly because they rarely measured whether participants actually raised their levels.

That is exactly why I prefer to test rather than debate: raise your measured index into range, and you have actually changed the biology the studies describe.

Getting your index up

• Food first: two to three servings of fatty fish per week.
• Supplementation: for most people it takes 1 to 2 grams of combined EPA and DHA daily to reach an index of 8 percent. Quality matters because fish oil oxidizes; I use Nordic Naturals ProOmega 2000 in my own stack.
• Retest after about 4 months, one red cell lifespan, to confirm your dose.

The takeaway

Do not guess about omega 3s in either direction. Test your index, dose to reach 8 percent, and retest.

This article is educational and is not medical advice. Discuss supplements with your physician, especially if you take blood thinners.