The Differences between Monounsaturated and Polyunsaturated Fats

By Jennifer Moll, PharmD  , Medically reviewed by Richard N. Fogoros, MD, Updated May 09, 2019

Saturated fats can adversely affect certain aspects of your lipid profile and increase risk for cardiovascular disease, which is why unsaturated fats—which have the opposite, positive affect—are preferred. There are two types: monounsaturated fat and polyunsaturated fat. Although they differ slightly, including both types in your diet can help improve your heart health and lipids..

Monounsaturated Fats

Monounsaturated fats have only one double bond in their molecular structure. They may help in maintaining the overall health of cells. Further, they can lower bad cholesterol, which reduces the risk for heart disease and stroke in the long run.

There are several healthy foods containing monounsaturated fats, including:

  • Cooking oils, including olive oil, sesame oil, and canola oil

  • Peanut butter

  • Nuts, including peanuts and cashews

  • Avocados

  • Olives

  • Sesame seeds

  • Healthy spreads labeled “high oleic”

Polyunsaturated Fats

Polyunsaturated fats differ from monounsaturated fats because they have more than one double bond in their structure. Much like monounsaturated fats, polyunsaturated fats can help lower bad cholesterol.  Polyunsaturated fats also contain omega-3 and omega-6 fatty acids, which your body needs for brain function and cell growth. 

Foods high in polyunsaturated fats include:
Seeds, including sunflower seeds and pumpkin seeds

  • Cooking oils, including corn oil, safflower oil, and soybean oil

  • Nuts, such as pine nuts and walnuts

A certain type of polyunsaturated fat, omega-3 fats, have specifically been studied regarding their effects on heart health and ability to lower lipid levels. Studies have shown omega-3 fats can lower triglyceride levels and slightly increase HDL (good cholesterol) levels. In fact, one 2016 study found eating fish high in omega-3 fatty acids, such as salmon, tuna, and sardines, at least twice a week significantly decreases blood triglyceride levels. 

The following foods contain this specific type of polyunsaturated fat:

    • Fatty fish, including salmon, mackerel, herring, and tuna

    • Seeds, including flax seeds and chia seeds

    • Walnuts

    • Algae (e.g., seaweed, spirulina, nori)

    Which One Is Best?

    Despite the slight differences in their chemical structure, both types of unsaturated fat have been linked to promoting heart health by improving lipid profiles, modestly increasing HDL cholesterol, and helping to lower LDL cholesterol (bad cholesterol) and triglyceride levels.

    Studies have shown that replacing saturated fats and trans fats with foods containing mainly monounsaturated and polyunsaturated fats can help protect you against heart disease.

Unsaturated fats are collectively referred to as “healthy fats” because they do not appear to promote the formation of  atherosclerosis, a waxy plaque that may build up in the arteries.

The American Heart Association recommends you replace foods containing saturated fats and trans fats with foods higher in monounsaturated and polyunsaturated fats.

Your fat intake should not consist of more than between 25 percent and 35 percent of the total calories you consume each day.

A Word From Verywell
Although foods high in monounsaturated and saturated fats are heart-healthy, you should not go overboard in consuming them. They are still high in calories, so work them into your diet strategically.