Polyunsaturated and monounsaturated fat are both unsaturated fats. “Poly” means many unsaturated chemical bonds and “mono” means one unsaturated chemical bond. These unsaturated fats are often found in liquid vegetable oils.
Polyunsaturated oils are liquid at room temperature and in the refrigerator. Common sources of polyunsaturated fat are safflower, sesame and sunflower seeds, corn and soybeans, many nuts and seeds, and their oils.
Monounsaturated oils are liquid at room temperature but start to solidify at refrigerator temperatures. Canola, olive, and peanut oils, and avocados are sources of monounsaturated fat.
Both types of unsaturated fats may help lower your blood cholesterol level when used in place of saturated fat in your diet. Remember to be moderate in your intake of all types of fat.
Poly- or monounsaturated oils — and margarines and spreads made from these oils — should be used in limited amounts in place of fats with a high saturated fat content, such as butter, lard, or hydrogenated shortenings.
By substituting monounsaturated fat in your diet for saturated and polyunsaturated fats you may be able to keep HDL cholesterol levels high and LDL cholesterol levels low. Overall the highest intake of fat should be from the monounsaturated type (12 – 20 percent of total calories).