A component together with glycerol in a 3 to 1 ratio that makes up fat. Alpha-linolenic acid (ALA), linoleic acid (LA) and arachidonic acid (AA) are not made by the body. These 3 essential fatty acids are necessary for health and must be obtained in the diet. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) can be made from ALA and arachidonic acid can be made from LA if there is sufficient amounts present. DHA, EPA, and AA should be included in a healthy diet.