Triglycerides: Fatty Acids and Glycerol

Very few fatty acids are found free in the body or in foods; most are incorporated into large, complex compounds: triglycerides. The name almost explains itself: three fatty acids (tri) arc attached to a molecule of glycerol to form a triglyceride molecule. Tissues all over the body can easily assemble triglycerides or disassemble them as needed. Fatty acids can differ from one another in two ways: in chain length and in degree of saturation. Triglycerides usually include mixtures of various fatty acids. Depending on which fatty acids are incorporated into a triglyceride, the resulting fat will be soft or hard. Triglycerides containing mostly the shorter chain fatty acids or the more unsaturated ones are softer and melt more readily at lower temperatures. Each species of animal (including people) makes its own characteristic kinds of triglycerides, a function governed by genetics. Fats in the diet, though, can affect the types of triglycerides made because dietary fatty acids are often incorporated into triglycerides in the body. For example, many animals raised for food can be fed diets containing softer or harder triglycerides to give the animals softer or harder fat, whichever consumers demand.