ABSTRACT
Lipid is a generic word for a diverse group of organic compounds. Lipids, as heterogeneous as they are, are usually classified as being either simple or compound lipids. The primary emphasis for the lipids, as it was for the carbohydrates, is to focus attention on the important dietary lipids. Dietary lipids of significant importance include the fatty acids, the triglycerides, cholesterol and esters of cholesterol, and the fat-soluble vitamins. Much can be learned about the nutritionally important lipids — their metabolism, structure, and function — by understanding the properties of the saturated and unsaturated fatty acids. Triglycerides, fats and oils, contain fatty acids of variable carbon chain length, e.g., mixed triglycerides, and various degrees of saturation or unsaturation. Usually classified as a simple lipid, cholesterol is the most widely distributed sterol in animal and human tissues. Dietary compound lipids are essential in the diet only to the extent that they provide calories, the mineral phosphorus, and esterified essential fatty acids.
