Understanding the names:
Omega-3, 5 & 6 fatty acids are poly-unsaturated fats while Omega-7 and Omega-9 fatty acids are mono-unsaturated fats. The name “Omega” indicates how far from the end of the molecule (i.e. the omega position is the last letter in the Greek alphabet) the first double bond occurs. In an Omega-3 fat it occurs on the third carbon atom from the end of the molecule, in an Omega-5 it occurs 5 from the end of the molecule and so on.
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© Dr. J. Renae Norton, http://www.eatingdisorderspro.com