Lower the omega-6 to omega-3 ratio in your diet

Omega-6 and omega-3 compete for the same enzymes — drowning out omega-3 with seed oils undermines supplementation.

Why it works

EPA and DHA compete with omega-6 arachidonic acid at the enzymes (delta-5 and delta-6 desaturase) that determine the balance between pro- and anti-inflammatory eicosanoids. The typical Western diet has an omega-6 to omega-3 ratio of approximately 15–20:1, compared to an estimated ancestral ratio closer to 4:1. High omega-6 intake shifts this balance toward inflammation and effectively caps how much EPA can influence neuroinflammatory tone, even when omega-3 intake is adequate.

How to do it

1. Reduce use of high-omega-6 seed oils (corn, sunflower, soybean, canola) in home cooking.
2. Switch to olive oil or avocado oil as primary cooking fats.
3. Be aware that most ultra-processed foods and restaurant cooking use seed oils — frequency of consumption matters.
4. You don’t need to measure ratios — reducing obvious seed oil sources while increasing fatty fish is the practical approach.

Evidence

The omega-6 to omega-3 ratio and its inflammatory implications are well characterized mechanistically. Epidemiological trends correlate rising seed oil consumption with rising inflammatory disease, though direct causal links for mood specifically are harder to isolate. (mechanistic)

The ancestral ratio figure is an estimate; the optimal ratio is not known. Mechanistic reasoning is sound but direct RCT evidence for ratio changes and mood is limited.

Sources

• Simopoulos (2002), The importance of the ratio of omega-6/omega-3 essential fatty acids, Biomedicine & Pharmacotherapy

Common mistake

Taking fish oil while continuing to consume large amounts of seed-oil-heavy processed food — you may be simultaneously supplementing EPA and competitively blocking its action.