According to Loren Cordain, author of The Paleo Diet (revised edition), our ancestors evolved eating a diet rich in vegetables, fruits, wild meats, fish, seafood, eggs, nuts and seeds. It provided a fatty acid profile of predominantly monounsaturated fats (omega-9), along with smaller quantities of saturated fat and the so-called 'essential fatty acids' (EFAs): polyunsaturated omega-3 and omega-6. Our evolutionary ratio of omega-3 to omega-6 was roughly 1:2. As regards EFAs, omega-3 is often lacking in the western diet and the omega-6 we eat is often damaged. What is the optimum dose of each? Impossible to say: different people need different amounts, depending on genetics, inheritance, diet and lifestyle. Seeking the advice of a qualified nutritionist is a good start.
Vital organs grab EFAs first so - as a rough guide - having enough for smooth skin and a shiny barnet suggests you are on the right path. Our hardware and software depend on fatty acids. They form part of our structure in phospholipid compounds, for example, which make up cell membranes. As cell membranes influence countless processes, we need to eat healthy fats, or messages can get scrambled. Fatty acids also grease our functioning (e.g. concentration and mood).
A critical phase in our evolution was driven by eating seafood from wetlands, swamp lands and the water's edge, and the brains of ruminant animals: all rich in omega-3. Our need for omega-3 is so great that studies have shown deficiency increases depression, arthritis, heart disease and the murder rate! (Holford) Molecules called prostaglandins, one of the four eicosanoid families of signalling molecules, control complex bodily processes and are made directly from EFAs found in fish and seeds. Prostaglandins influence everything from hormone balance to brain response.
Our obsession with low-fat diets plus eating refined fats in processed foods may have contributed to the rise of depression, aggression, heart disease and arthritis in the 20th and 21st centuries. Healthy fatty acids allow our brains, hearts, blood vessels and immune systems to function well. They control pain and inflammation; improve mood; preserve memory; and beautify skin and hair. They are, indeed, essential to life.