Believe it or not, our bodies can synthesize all the fat it needs, and saturated, monounsaturated, and trans fat (including cholesterol) do not need to be consumed through the diet. Omega-3 and omega-6 are the only two which the body cannot synthesize and therefore they are considered essential fats.
Technically, only one kind of omega-3 needs to be obtained through our diet: Alpha-lenolenic acid (ALA), which has the ability to produce other omega-3 fatty acids in the body such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, this conversion of ALA to EPA and DHA is relatively limited, and it is often recommended that EPA and DHA be consumed through the diet as well, either through food source or supplements. The Omega-6 that needs to be obtained from the diet is called Linoleic acid (LA).
But how much omega-3 and omega-6 do we need to consume in the diet?
ALA (omega-3) and LA (omega-6) compete for metabolism, which means too much of either one will reduce the metabolism of the other. This is one of the reasons a recommended ratio of 1 (or about 2:1) for omega-6 to omega-3 was developed (1). Unfortunately most Americans consume excessive amounts of omega-6 and are deficient in omega-3, with an average ratio of 16:1!
Both omega-3 and -6 play essential roles in brain function, normal growth and development. The high ratio of omega-6 to omega-3, however, promotes the pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases (3). Omega-3 (a low omega-6/omega-3 ratio), on the other hand, has been shown to prevent against these major diseases and also help control lupus, eczema, and rheumatoid arthritis (2).
The high ratio of omega-6 can be attributed to grain fed animals (including the meat, dairy, and eggs that come from them), mayo-based foods, and the increased vegetable oil consumption: safflower, sunflower, corn, and soybean oils, coming from processed foods and cooking methods.
Remember, the idea is that both of these fatty acids are essential for proper health and play a role in the prevention of many diseases. The key is balance between the two. It’s very easy to consume omega-6 in our diet, and a bit tricker to get those omega-3’s. Here are the top sources of omega-3 (which also have low ratio of omega6/3):
- Flax seeds*
- Hemp seeds*
- Chia seeds
- Beans, leafy greens, squash-help meet the RDA (4)
- Supplements for ALA, DHA, or EPA
- Fatty fish (good sources include anchovies, herring, salmon, sardines, rainbow trout, and pacific oysters) & shellfish
*Including their oils.