What is OMEGA-3?
Omega-3 (ω−3, n-3) is a family of unsaturated fatty acids, of which three are most important for human health: α-linolenic acid (ALR, C18:3), eicosapentaene (EPR, C20:5) and docosahexaenoic acid (DHA, C22:6).
What does "unsaturated omega-3 fatty acid" mean and how to code the names and designations of omega acids?
In order to talk about fatty acids, it is very useful to first clarify and define the often confusing and unclear terms used to describe them. All fatty acids that bear the name omega are unsaturated. "Unsaturated" means that the molecule of this acid has one or more double bonds between carbon atoms in its structure. Depending on where in the molecule, i.e. at the raised carbon atom, counting from the last in the chain, there is a double bond, omega fatty acids are divided into omega-3 (at the third carbon atom there is the first double bond, counting from the end of the chain), omega -6, omega-9, etc
According to the number of carbon atoms, fatty acids are divided into short chains with 19 carbon atoms and less and long chains with 20 carbon atoms and more. According to this, ALR is classified as short-chain unsaturated fatty acids, while EPR and DHA are classified as long-chain fatty acids. The number of carbon atoms in the chain is indicated after the letter C, e.g. the formula EPR C20 says that this acid has a chain of 20 carbon atoms.
Omega-3s are called polyunsaturated fatty acids because they have more than one double bond. The number of double bonds is indicated after a colon after the number of carbon atoms. For example, EPR C20:5 would be encrypted as follows: eicosapentaenoic acid, which has a chain of 20 carbon atoms in its structure and 5 unsaturated (double) bonds between them.
The n-3 or ω−3 next to the name indicates which carbon atom has the first double bond. For all omega-3 acids, it is at the third carbon atom and will be denoted n-3 or ω−3. For example, EPR C20:5 n-3.
The basic omega-3 acid is ALR. Humans, like all mammals, cannot synthesize ALR by themselves, so it must be obtained from food and is called indispensable. Meanwhile, the body can produce EPR and DHA from ALR. However, studies show that the amounts converted are relatively insignificant. About 6 percent ALR turns into EPR and less than 4 percent. – DHA.[1] It is also very important to mention that how much ALR exceeds EPR and DHA depends on the amount of omega-6. A diet rich in Omega-6 can reduce the conversion of ALR into EPR and DHA by up to 50% [1],[2]
[1] Gerster, Helga. "Can adults adequately convert a-linolenic acid (18: 3n-3) to eicosapentaenoic acid (20: 5n-3) and docosahexaenoic acid (22: 6n-3)?" International journal for vitamin and nutrition research 68.3 (1998): 159-173.
[2] Brenna, J. Thomas. "Efficiency of conversion of α-linolenic acid to long chain n-3 fatty acids in man." Current Opinion in Clinical Nutrition & Metabolic Care 5.2 (2002): 127-132.