Omega-3 vs Omega-6: Why the Ratio in Your Diet Matters

You have probably heard that omega-3 fatty acids are good for you. Fewer people know the full story — which is that the ratio of omega-3 to omega-6 in your diet may be just as important as the absolute amount of either.

What These Fatty Acids Do

Both omega-3 and omega-6 are polyunsaturated fatty acids. Omega-6 fatty acids (primarily linoleic acid) are pro-inflammatory in excess — they are precursors to compounds that promote inflammation. Omega-3 fatty acids (ALA, EPA, DHA) are anti-inflammatory — they compete with omega-6 for the same metabolic enzymes and produce anti-inflammatory compounds. The balance between them determines much of the inflammatory signalling in your body.

The Modern Diet Problem

The ancestral human diet is estimated to have had an omega-6 to omega-3 ratio of around 4:1 or lower. The modern Western diet averages 15:1 to 20:1. The primary driver is vegetable oils — sunflower, corn, and soybean oils are extremely high in omega-6 and are now present in virtually every processed food. Ultra-processed foods, fast food, and most restaurant cooking use these oils extensively.

Getting More Omega-3

The most bioavailable omega-3s are EPA and DHA, found in oily fish (salmon, mackerel, sardines, herring), shellfish, and algae (the original source for fish). ALA, found in flaxseed, chia, and walnuts, must be converted to EPA and DHA in the body — conversion rates are typically 5-10%, making plant sources far less efficient. The EFSA recommends 250mg of EPA plus DHA per day for general health. Two portions of oily fish per week typically achieves this.

What to Change

Reduce sunflower, corn, and soybean oils in favour of olive oil and butter for cooking. Add fatty fish 2-3 times per week. Consider algae-based EPA/DHA supplements if you do not eat fish. These changes alone can meaningfully shift your omega-3:6 ratio within weeks, as reflected in blood tests measuring erythrocyte fatty acid composition.