Total EPA+DHA

This is EPA and DHA added together rather than weighed against each other. The panel measures each one separately, and this row sums them, which gives the total long-chain omega-3 circulating in your blood at the time of the sample.

It answers a different question from the two ratios beside it. The DHA to EPA ratio tells you what your omega-3 supply is made of. The omega-6 to omega-3 ratio tells you how it compares to the linoleic acid competing with it. This number tells you how much there is in absolute terms, which is the quantity a change in diet or dose moves directly.

On this panel, 100 to 350 umol/L reads as in range and 150 to 350 umol/L as optimal. Below 100 sits in the band worth acting on.

Read it next to your Omega-3 Index, which measures the same two fatty acids as a percentage of the fats in your red cell membranes. The index reflects the last three to four months. This serum figure reflects recent weeks, so the two can disagree after a change in intake, and that disagreement is informative rather than an error.

Below 100 umol/L means there is little EPA and DHA in circulation. In practice this is a diet with almost no oily fish and no omega-3 supplement, which describes most people who have never had reason to look.

The body can make EPA and DHA from the plant omega-3 in flax, chia and walnuts, but the conversion is inefficient. Estimates for the alpha-linolenic acid that becomes EPA sit in the low single-digit percentages, and the fraction reaching DHA is smaller again. Relying on that pathway is the usual reason a plant-heavy diet lands here despite looking omega-3 rich on paper.

A high linoleic acid intake makes it harder still, since the same enzymes handle both families and the one supplied in bulk wins. Cutting seed oil intake raises this number even when omega-3 intake has not changed.

Between 150 and 350 umol/L your combined EPA and DHA sits in the optimal band, and 100 to 350 still reads as in range.

Two portions of oily fish a week is the intake that usually gets people here without supplementing. A single daily capsule of a concentrated fish oil does the same for most people who do not eat fish.

Once here, the question shifts from how much to what mix, which is what the DHA to EPA ratio answers.

Above 350 umol/L is uncommon and generally reflects a high supplemental dose rather than food, since it takes an unusual amount of fish to reach it.

Very high intakes lengthen bleeding time, which matters if you are on anticoagulant medication or have surgery scheduled. Raise it with your practitioner rather than adjusting a prescribed medication yourself.

The other consideration is oxidation. Long-chain omega-3s are fragile, and a large dose of a poorly stored oil delivers more oxidised fat along with the omega-3. Buy smaller bottles, keep them cold, and stop using one that smells of fish.

Fish intake has fallen while intake of the omega-6 that competes with it has risen sharply, so this marker moves down from both ends at once. That is the pattern the Dietary Alignment domain of the Western Lifestyle Index is built to catch.

Farmed fish complicates the picture. Feed formulations have shifted toward plant oils over the last two decades, and the EPA and DHA content of some farmed species has fallen with them, so a portion of salmon does not necessarily deliver what the same portion delivered twenty years ago.

Sockeye and other wild salmon, mackerel, sardines, anchovies and herring are the densest sources. Two portions a week is the usual target.

The small oily fish are worth favouring. They are cheaper, they carry less accumulated mercury than large predatory species, and tinned versions count in full.

Shellfish, roe and pastured eggs contribute smaller amounts. Flax, chia and walnuts supply the plant precursor rather than EPA and DHA themselves, so they help less than their reputation suggests.

A concentrated fish oil supplying a combined 1000 to 2000 mg of EPA and DHA daily is the usual correction. Read the EPA and DHA figures on the label rather than the total fish oil weight, which is a larger and less useful number.

Algal oil is the option that does not depend on fish, and it supplies DHA directly rather than the precursor. Products combining algal EPA and DHA exist and cost more.

Take it with a meal that contains fat, since absorption depends on it. Triglyceride and re-esterified triglyceride forms absorb somewhat better than the ethyl ester form.

Retest after three to four months. This figure responds faster than the Omega-3 Index, but leaving both the same interval keeps the two comparable.