Monounsaturated and polyunsaturated fats are generally found in plants and are touted as healthy fats, unlike trans fats, saturated fats and cholesterol. Organizations such as the American Heart Association (AHA) encourage people to switch to foods based on monounsaturated and polyunsaturated fats from those that contain saturated and trans fats, which are generally processed fats or come from animal-based fat sources such as butter or meat products. Food often contains a combination of different types of fats.
Monounsaturated and Polyunsaturated Fat
Monounsaturated fats are made up of a chain of carbon with one pair of carbon molecules joined by a double bond. The more double bonds there are, the more solid the fat will be. Monounsaturated fats are generally liquid at room temperature, but turn slightly solid when chilled. Polyunsaturated fats have two or more double bonds between carbon atoms in the carbon chain backbone of the fat. They are more solid than monounsaturated fats but less so than saturated fats. This makes polyunsaturated fats also liquid at room temperature.
Both monounsaturated fats and polyunsaturated fats have distinct health benefits. There is evidence that both types of fats reduce LDL cholesterol levels in the blood when included in a diet low in saturated and trans fats, according to the AHA. This helps lower risk of coronary artery disease and stroke. Monounsaturated fats have the added benefit of being high in Vitamin E and in helping to maintain or develop cells in the body.
Essential Fatty Acids
Your body needs two types of polyunsaturated fatty acids -- omega-3s and omega-6s -- from your diet, because your cells cannot make these fatty acids themselves. Both omega-3 and omega-6 fatty acids contribute to brain function. Omega-3 fatty acids also reduce inflammation and lower your risk of cardiovascular disease.
Monounsaturated fats are found in olive oil, peanut oil, canola oil, avocados, nuts and seeds. Polyunsaturated fats are found in many vegetable oils, including safflower, corn, sunflower, soy and cottonseed oils, as well as in nuts and seeds. The omega-3 fatty acids can be found in flaxseeds, walnuts and some fatty fish, such as salmon and herring, while omega-6 fatty acids found in pecans, Brazil nuts and sesame oil.
While they have shown health benefits, monounsaturated fats and polyunsaturated fats are still fats and should not be consumed overabundance. Like all fats, they have 9 calories per gram. The AHA says evidence has not shown one to be better over the other for health. Fats overall, including these two types, should make up less than 25 percent to 35 percent total daily calorie intake, the AHA says.