Polyunsaturated Fat

Polyunsaturated fatty acids have more than one double bond in its respective molecule and polyunsaturated fat is an abbreviation for polyunsaturated fatty acids or PUFA. Depending on the geometry of the double bond, polyunsaturated fatty acid can be of cis or trans conformation. Polyunsaturated fatty acids are liquid at room temperature and do not solidify when refrigerated. The melting point of polyunsaturated fats is also very low compared to saturated fatty acid or monounsaturated fatty acid as the extra hydrogen atom on the surface is lacking that causes reduced strength of intermolecular forces. Trans fats are very similar to saturated fatty acids, along with the fact that at low temperatures they solidify.

A fatty acid molecule has a methyl group at one end and carboxylic acid at the other. Carbon atoms in it are identified on the basis of their distance from the carboxylic acid. The first carbon atoms are identified by Greek letters, the carbon atom next to carboxylic acid is named alpha, and the one adjacent to alpha is beta and so on. The last atom in the Greek letters is omega and thus the carbon atom in the methyl group is named omega in the long fatty acid chain. As the name suggests omega-3 fatty acid has double bond three carbons away from the methyl carbon and omega-6 has double bond 6 carbons away from the methyl carbon.

Along with monounsaturated fatty acids, polyunsaturated fatty acids are also classified as healthy fats. But how much ever healthy a fat is, its consumption should not exceed beyond the recommended levels in the diet. The main food sources of PUFA are grain products, fish, seafood that include salmon, mackerel, herring, halibut, fish oil and soybeans. Soft margarine and mayonnaise are also good sources of PUFA but the amount will vary depending on the brand and style. Polyunsaturated fatty acid protects our body against many illnesses. Fish, fish oil and sea food that are good source of omega-3 fatty acid can help lower blood pressure, total amount of fat and reduce the risk of cardiovascular diseases. Safflower and sunflower oil that are good source of omega-6 fatty acid may also reduce the risk of cardiovascular diseases, but on the other hand can also contribute to inflammation and allergies.

Some studies show that the risk of developing cancer in healthy individuals increases with excess consumption of polyunsaturated fatty acids. This may be due to the fact that polyunsaturated fatty acids are more prone to oxidation that leads to generation of free radicals in the body.

Although the effects of polyunsaturated fatty acids are more beneficial than harmful, it is necessary to regulate the amounts of total fats and PUFA in the diet.

Submitted on September 4, 2008