Wednesday, April 28, 2010

Essential Fatty Acids - Part 1

Fatty acids are organic, carboxylic acids consisting of long, unbranched chains of hydrocarbons. Fatty acids can be either saturated, with no double or triple bonds (top left), or unsaturated, containing one or more (polyunsaturated) double or triple bonds (top right).

Unsaturated fatty acids can be found in either the cis or trans configuration.

In the cis configuration, the hydrogen atoms are found on the same side of the double bond. In the trans configuration, the two hydrogen atoms are on the opposite side of the double bond. Fatty acids in the cis congiguration are bent or kinked. This affects their melting temperature resulting in the fats being liquid at room temperature.

The human body can make most of the fatty acids it needs. However, there are two essential fatty acids the body cannot make. These fatty acids, linoleic and alpha-linoleic acids, must be ingested because humans lack the enzymes necessary for producing double bonds at the Omega-3 and Omega-6 positions. Omega-3 and Omega-6 are made from the two essential fatty acids. These acids are catagorized based on their physiological properties using the n-x nomenclature.

The top fatty acid pictured is named using the conventional nomenclature for fatty acids where the first double bond is counted from the carboxy end of the molecule (the COOH end). The Omega-x (or w-x)nomenclature is the opposite. The location of the first double bond is counted from the methyl end of the molecule. In the above case, the first double bond is located at the 3rd carbon and the second double bond is located at the 6th carbon.

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