The omega-6:3 ratio: what the number means, and what it doesn't

Omega-6 and omega-3 are two families of polyunsaturated fatty acids. The body needs both, and it cannot make either from scratch. The question is not whether you get omega-6, because almost everyone does, but what the balance between them looks like.

What the number means

The ratio says how many parts omega-6 there are for each part omega-3 in your blood sample. A ratio of 12:1 means twelve times as much omega-6 as omega-3. A ratio of 3:1 means three times as much.

The number comes from a fatty-acid test, where the laboratory measures the fatty acids in a dried blood spot. It describes what is actually in your blood, not what you think you eat.

Why many people are high

Much of the omega-6 in a typical diet comes from cooking oils, margarine, processed food, snacks and meat from grain-fed animals. Omega-3, especially EPA and DHA, comes mainly from oily fish.[source pending] Eat little oily fish and a lot of processed food, and the balance tips towards omega-6. The starting point in the illustration below stands in for a typical Norwegian diet.[source pending]

Why the balance is interesting

Omega-6 and omega-3 are built into the membranes around your cells, and they partly compete for the same places and enzymes.[source pending] The ratio therefore says something about how the fat in your diet has settled in your body over time.

A ratio of around 3:1 or lower is often used as a reference point when laboratories report the number.[source pending] A high number is not a diagnosis. It is a signal about fat balance.

Why the number should never stand alone

The same ratio can come from very different diets, for example little of both or a lot of both. So I always read it together with:

• The Omega-3 Index, which shows how much EPA and DHA you actually have in your red blood cells.
• The AA:EPA ratio, which compares one specific omega-6 with one specific omega-3.
• The rest of the fatty-acid profile.

What moves the balance

There are two levers: more omega-3 and less omega-6. In practice that usually means oily fish for dinner or on bread a couple of times a week, and a little less of the processed products that supply the most omega-6. My recipes are built for exactly that.

Change happens gradually, because fatty acids in red blood cells are replaced over about four months.[source pending] That is why I retest around 120 days after the first test, and why I never promise a particular result in a particular time.

Want to know where you are?

The illustration below is only a model. Your own number needs a test. Start with the free 2-minute check, or read what a test can and can't tell you.

Sources

1. [source pending] Source needed: Norwegian dietary guidance on fatty fish and food sources of omega-3 (Helsedirektoratet)
2. [source pending] Source needed: Norwegian intake data (e.g. Norkost) or test data on the typical omega-6:3 ratio in Norwegian adults
3. [source pending] Source needed: review on arachidonic acid (AA) and EPA sharing the same enzymes and membrane positions
4. [source pending] Source needed: where the commonly used reference point of about 3:1 (or lower) for the omega-6:3 ratio comes from, and how it is used by laboratories
5. [source pending] Source needed: review discussing the usefulness and limits of the omega-6:3 ratio as a marker
6. [source pending] Source needed: red blood cell lifespan (~120 days) and how fast membrane fatty acids change