Saturated fatty acids most frequently occur in higher concentrations in animal foods such as butter, cheese, and fatty meats; however, there are certain exceptions to this rule, and plant-derived fats such as coconut and palm oils are also extremely high in saturated fatty acids. In fatty foods, the most common saturated fatty acids are lauric acid (12:0), myristic acid (14:0), palmitic acid (16:0) and stearic acid (18:0). Excessive consumption of 12:0, 14:0 and 16:0 elevate blood concentrations of total and LDL cholesterol but recent meta analyses (combined large population studies) demonstrate they don’t increase your risk for heart disease. Stearic acid (18:0) is neutral and neither raises nor lowers blood cholesterol. Below is a list of the common and numeric names for saturated fatty acids that may occur in foods. Notice that most saturated fatty acids are even numbered. Odd numbered saturated fatty acids rarely are present in foods.
Saturated fatty acids (and all fatty acids) are comprised of chains of carbon atoms connected to one another by chemical bonds. The numeric name therefore represents the number of carbon atoms within the saturated fatty acid chain. Below is a schematic diagram of lauric acid, or 12:0. Lauric acid is labeled 12:0 because it is 12 carbon atoms in length, and it contains no double bonds (=), but only single bonds (-) linking the carbon atoms. Note that there are two ends to all fatty acids, one called the omega end, containing a methyl (CH3) group, and the other that contains a carboxyl (COOH) group. Lauric acid and all saturated fats are “saturated” because the carbon atoms are completely filled with hydrogen atoms.
The schematic diagram above is not precisely correct because it does not show the correct angle of the carbon-to-carbon bonds, which really is 109 degrees rather than 180 degrees. In the diagram below, you see a geometrically correct diagram of lauric acid. Note that each carbon atom is numbered starting from the carboxyl (COOH) end of the fatty acid. The geometrical configuration of the carbon-to-carbon bonds (109 degrees) is important because it determines the shape of the fatty acid, particularly as we consider monounsaturated and polyunsaturated fatty acids.