The fats in our food are important because they are carriers of the fat-soluble vitamins: A, D, E, and K. In addition, dietary fat includes and supplies essential fatty acids, particularly linoleic acid.
All animal life requires polyunsaturated fatty acids, and linoleic acid is of primary importance to humans. The adult requirement is low, and easily met by a well-rounded diet, but children have a greater need for linoleic acid for growth. The essential fatty acids are important in preventing drying and flaking of the skin and have several metabolic roles: maintaining cell membranes, regulating cholesterol metabolism, and helping to create hormone-like substances needed for many body processes. But what, in fact, are these fatty acids? The fats in our body contain the same substances as the fats in our food: fatty acids and f atlike compounds called phospholipids (such as lecithin) and cholesterol.