Unsaturated Oils: Structure and Food Sources


Cell membranes are composed of lipids (fats).  As raw materials for the body to construct healthy cell membranes and for proper cell function, the body needs both saturated fats for structure and unsaturated for flexibility.

Saturated fat molecules have no double bonds along the carbon chain–all carbon atoms are saturated with hydrogens, lending stability. In contrast, unsaturated fats are more reactive.  Along their carbon chain, they have one or more double bonds–places where carbon atoms are not paired with a full complement of hydrogens.   At these double-bond “hot spots” they are more vulnerable to oxidative stress and free-radical damage.  While the more double bonds, the more fragile, the more double bonds, the more effective these oils are to provide the body with materials necessary for cellular communication and neurological function.

This table, adapted from Elson Haas, illustrates food sources of a variety of unsaturated oils.  Note the 5 and 6 double bonds of fish oils, a reason fish are thought to be “brain food.”

Source: Adapted from Elson Haas, Staying Healthy With Nutrition

Type of Fatty Acid
Key Fatty Acid
Double Bonds
Best Sources
Monounsaturated Omega-9Oleic acid18 carbons 1 Olive oil
Polyunsaturated Omega-6sLinoleic acid18 carbons 2Safflower, sunflower, Sesame, and Gragpesee Oils
Gamma-linolenic acid18 carbons 3Borage, Evening Primrose Oils
Arachidonic acid20 carbons 4Beef fat, Egg Yolk
Polyunsaturated Omega-3sAlpha-linolenic acid18 carbons 3Flax, Pumpkin, Hemp, Seeds and Walnuts
Eicosapentaenoic acid (EPA)20 carbons 5Fish oil
Docosahexaenoic acid (DHA)22 carbons 6Fish oil
Source: Adapted, Elson Haas