Fatty acids and Essential fatty acids
Fats are made up of smaller components called fatty acids. The body can make some of the fatty acids it needs for growth but cannot manufacture the essential fatty acids. EFAs are called ‘essential’ because the body cannot produce them and they therefore need to be consumed on a daily basis in your diet. Most EFAs come from polyunsaturated fats. Essential fatty acids (EFAs) have important functions similar to vitamins. It is vital to eat them to stay healthy. EFAs are present in every cell in the body and are vital for good health. These fats make up a major portion of the brain and nervous system.
Are we getting enough?
Early humans were hunter-gatherers who ate green plants, fruit, nuts, berries, fish and lean meat. This diet contained predominantly unsaturated fats rich in omega-3 fatty acids. However, the modern diet is characterized by a high intake of animal fat containing saturated fatty acids, as well as mainly omega-6 fatty acids from staple foods such as wheat, rice, maize and sunflower seed oil. Consequently, the omega 3:6 ratio has changed from 1:4 to nearly 1:15. This is thought to have contributed to the rising incidence of lifestyle and dietary-induced diseases such as depression, cardiovascular disease, obesity, diabetes and osteoporosis.
We eat many sources of omega-6 fatty acids, but omega-3’s are often difficult to consume in adequate amounts as they are only found in very specific foods. The two key Omega 3 fatty acids are EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid). An enzyme called delta-6 desaturase is required to convert the ‘parent’ EFAs into their active forms. If the activity of this enzyme is reduced or inhibited in some way, a deficiency of the key EFAs may arise. A number of common factors can adversely affect this enzyme, including high alcohol intake, caffeine, smoking, ageing, excessive intake of cholesterol and saturated fat, high sugar consumption, many vitamin deficiencies (zinc, chromium, vitamin B6), viral infections and diabetes. So even with what appears to be a well-balanced diet, complete with all the correct sources of EFAs, a blockage of the metabolic pathway caused by the inhibition of delta-6 desaturase can actually leave one with a deficiency of EFAs. The FADS1 gene pathway also affects this process. Cold water fish such as salmon, tuna, mackerel and pilchards give a direct input of DHA. Similarly, evening primrose oil is an excellent source of GLA, which is easily converted in the body to AA. However, the doses of EFAs required to have specific health benefits are often too high to be getting enough from diet alone, and supplementation is therefore required for many people.
The delta-6 desaturase enzyme is needed for the activation of both omega-6 and omega-3. If we eat a lot of omega-6, they compete for the use of the enzyme, and therefore reduce the amount of delta-6 desaturase needed to convert omega-3’s into EPA and DHA. If you want the benefits of omega-3s, you should take them by themselves, and not with omega-6’s.
Quality of fish oil supplements
It is important for fish oil to be tested for contaminants that may be present in marine derived products, like heavy metals, dioxins and PCBs. This assures a higher level of purity, safety and quality for the end user. Metagenics, Xymogen and Solgar products carry the guarantee of extensive third party testing to verify purity and potency of their fish oil products.
Dietary sources of essential fatty acids
As with all nutrients, the best source to obtain them from is food, rather than supplements. However this may be difficult for many individuals as fatty fish can be expensive and may not be a preference. The main food source, which contains the active form of EPA and DHA, is fatty, cold water fish (salmon, fresh tuna, pilchards, sardines, mackerel and herring). Another animal source option is omega-3 enriched eggs. Plant sources high in omega 3 include walnuts, chia, pumpkin and linseeds, but these must still be converted to DHA and EPA and this conversion is often not performed optimally in the body.
The omega-3 content of various fishes is listed in the table below:
(150g raw weight)
Total Omega-3 (g)
(including DHA and EPA)
|Sardines in Sardine oil||23.25||4.95|
|Pilchards in brine||8.10||2.42|
|Tuna in brine||3.75||0.75|
|Omega-3 eggs (per egg)||5.9||0.32|
As already mentioned, we usually get enough omega-6’s, but not omega-3’s. Omega-3 fatty acids have beneficial effects on a number of different diseases. They are known to:
- Reduce the risk of heart disease.
There are a number of ways in which they do this:
- they have a slight impact on lowering blood pressure
- they reduce triglyceride levels
- supplementation has been shown to lower LDL (bad cholesterol) and increase HDL (good cholesterol)
- they make blood ‘thinner’ and less likely to clot, reducing the risk of blocked arteries and veins.
- Have a positive effect on autoimmune diseases.
Omega-3 fatty acids decrease inflammation, and support the immune system. They have been shown to be beneficial in autoimmune or inflammatory conditions such as Crohn’s disease, rheumatoid arthritis, and SLE (Lupus).
- Promote good brain and eye development in children.
Omega-3 fatty acids are vital for the growth and development of the foetal nervous system and retina during pregnancy, and for the growth of the brain of infants up to at least 2 years of age.