Figure 2: A. Unsaturated fat with two double bonds between the carbon atoms. B. Saturated fat with no double bonds between carbons.
The shape of the fat molecule plays a major role in how these fats function in the body. The saturated fats are solid like lard and butter, whereas the unsaturated fats tend to be liquid, as we see with the vegetable oils. Within cells this can determine how well the membrane works. Saturated fats interfere with the movement of special molecules that normally travel along the membrane. We call this property fluidity. Polyunsaturated fats increase fluidity and saturated fats reduce fluidity.
Normally, fats in nature are fully hydrogenated; that is, all the carbon atoms have a full complement of hydrogen atoms. In order to make liquid fats, such as corn oil, into hard fats that can be used in margarine, food chemists add hydrogen atoms to the oil. This requires heat, pressurized hydrogen, and a metal catalyst. Because the fully saturated fats are too hard, the chemists partially hydrogenate the oil, leaving some of the double bonds, hence the name partially hydrogenated oil.
In nature, both of the hydrogen atoms attached to the carbon atoms making up the double bond are located on the same side. We call this a cis configuration. For example, oleic acid is referred to as cis-9-octadecenoic acid in the language of organic chemistry. When the hydrogen atoms are on opposite sides it is referred to as a trans fat. The cis form is bent while the trans form is straight as an arrow.
Because the trans fats have a straight configuration, they no longer fit into the cell membranes properly, making the cell function abnormally. In addition, the trans form interferes with certain enzymes, leading to things like atherosclerosis, heart attacks, strokes, and degenerative brain disorders. For decades, the USDA and their scientists denied that trans fats were harmful. It was the untiring efforts and scientific work of lipid scientist Dr. Mary G. Enig that eventually exposed the health disaster related to these fats. Millions of unsuspecting and trusting Americans were harmed and many died because of this collusion between industry and government, something previously called fascism.
Fatty acids are named in several ways. First, they are classified according to the number of carbon atoms they possess, usually from one to twenty-four. At one end of the long chain of carbon atoms is an acid group (called a carboxyl group and designated COOH). This acid group can react with a number of molecules, including cholesterol and glycerol. At the other end is a methyl group (CH3). This is called the omega end of the molecule.
The designation for unsaturated fats is the delta symbol, A, which tells where the double bond is located. For example, A-9 means the double bond is located at the ninth carbon counting from the acidic end of the fatty acid.
Most people have heard of omega-3 fatty acids. The use of the term omega (or with the Greek symbol Q) comes from the older chemical nomenclature. It simply means that the first double bond is to be found on the third carbon atom counting from the methyl end of the molecule, the omega end.
When scientists get bored, they like to rename everything, which can keep laymen confused. The new chemical term for omega-3 oils is N-3 oils. Corn, safflower, sunflower, peanut, and soybean oils are referred to as N-6 oils, as is alpha-linoleic acid. Olive oil contains the N-9 oil called oleic acid.
Trans-form of unsaturated fatty acid. The hydrogens are on opposite sides of the carbon.
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