Essential fatty acids (EFAs) are unique in their beneficial qualities–and near absence in our modern diet. EFAs play an important role in human nutrition and health. They are called “essential” because the body cannot manufacture these vital polyunsaturated fats; they must be obtained from our diet. There are three types of EFA: omega-6 and omega-9, both of which are plentiful in our diet, and omega-3. The body’s optimal balance between omega-6 (linoleic) and omega-3 (linolenic) fatty acids is a 2:1 to 4:1 ratio. Unfortunately, the typical Western diet contains these acids in ratios of 20:1 to 25:1.
This ratio is critical, and an excess of omega-6 fatty acids can lead to the formation of blood clots, allergic and inflammatory disorders, and the accelerated growth of certain cancer cells. Oxidation of omega-6 EFA and the production of arachidonic acid lead to increased inflammation, reduced blood flow, and free-radical damage. Omega-3 EFAs counter these effects; therefore, the consumption of omega-3 EFAs is crucial. There is some support for a couple of special omega-6 EFAs, namely gamma-linolenic acid (GLA) and conjugated linoleic acid (CLA); we’ll examine them later.
Omega-3 EFAs have three primary types: alpha-linolenic acid (ALA), the more beneficial longer-chain eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is found in plant sources. The plant-sourced ALA has two drawbacks. First, the plant sources (flaxseed, purslane, walnuts, pumpkin seeds) usually provide unneeded omega-6 in addition to omega-3. Second, the efficiency of converting ALA to EPA and DHA varies among individuals. While EPA is readily synthesized in the body from alpha-linolenic acid, the synthesis of DHA is much more difficult.
It is, therefore, more advantageous to acquire EPA and DHA directly. The sources richest in EPA/DHA content are marine algae, the animals that consume them, and especially fatty fish farther up the food chain. The fish with the highest concentration of EPA/DHA oils are sardines, anchovies, herring, and some mackerels, but they don’t make such great meal entrees. Salmon also have plentiful EPA/DHA, but occupying the top of the food chain, salmon are often high in heavy metals and toxins from ocean pollution. Farmed salmon, while avoiding most of the heavy metal toxins, contain undesired antibiotics and flesh coloring chemicals. Because of the farm diet, they also contain much higher levels of omega-6 EFAs.