Omega 3 and Omega 6 fish oils are believed to provide benefits for a wide range of problems including dyslexia, ADHD and autism. However the many different types of fish oils and seed oils it can get confusing.
Alpha-Linolenic Acid (ALA) and Linoleic Acid (LA)
ALA and LA are the fatty acids generally referred to as Omega 3 and Omega 6. They are found in some seeds and dark leafy vegetables. They are an essential part our diets (and sometimes called essential fatty acids) because we have to get them from an external source as the body cannot create or store them in the body. In scientific literature linoleic acid is referred to as 8:2(n-6) and alpha-linolenic acid as 18:3(n-3)
Stearidonic Acid (SA) and Gamma-Linolenic Acid (GLA)
After the linoleic acid and alpha-linolenic acid enter the body they are converted into SA and GLA. Evening primrose oil naturally contains GLA and GLA is often seen as the best form to take omega-6 fatty acids which is why evening primrose oil is often used in dietary supplements.
Eicosatetraenoic Acid (ETA) and Dihomo-Gamma-Linolenic Acid (DGLA)
Eicosapentaenoic Acid (EPA) and Arachidonic Acid (AA)
These two fatty acids are critical for the human body. AA plays a role in more than twenty different signalling paths that control a bewildering array of bodily functions, but especially those functions involving inflammation and the central nervous system. EPA softens the inflammatory effects of AA and low dietary intake of EPA is associated with a variety of inflammation-related diseases.
Docosahexaenoic Acid (DHA) and Docosapentaenoic acid (DPA)
The final step in the chain is DHA and DPA. These are the actual substances used in the body and have been linked to mental health problems such as ADHD and depression and also physical problems like heart disease.
Though the body can convert ALA to DHA and LA to DPA, a lot of these fatty acids can be found directly in food. For example oily fish is high in EPA. It is not clear whether it is better to take the ALA or LA and let the body convert it or start as far down the chain as possible with EPA or AA. Arguments can be made for both approaches.