What Are Saturated and Unsaturated Fatty Acids?

Fatty acids can differ in their degree of saturation. Saturation refers to whether all of the carbon atoms between the end carbons are linked to two atoms of hydrogen. If this is the case, then the carbons are saturated with hydrogen and that particular fatty acid would be called a saturated fatty acid (SFA) (Figure 5.3). However, if, at one or more points, adjacent carbon atoms are bonded to only a single hydrogen atom each, the fatty acid would then be an unsaturated fatty acid (see Figure 5.3).

By nature, when two adjacent carbon atoms in a fatty acid are linked to only one hydrogen atom each, the carbon atoms must bond to each other twice. Chemists call this a double bond and if a fatty acid has only one double bond, it is referred to as a monounsaturated fatty acid (MUFA). Meanwhile, if there is more than one double bond, then it is a polyunsaturated fatty acid (PUFA).