Monounsaturated and Polyunsaturated Fats Differences

There are two main categories of fat: saturated and unsaturated fats. Saturated fats can adversely affect certain aspects of your lipid profile and can increase your risk for cardiovascular disease — especially if you consistently consume a diet high in saturated fat. Unsaturated fats, on the other hand, can have a positive effect on your heart health — and your lipid profile.

Unsaturated fats differ from saturated fats in that they have a double bond somewhere in their chemical structure, which causes them to be bulkier when interacting with other unsaturated fat molecules. This results in these fats being more fluid at room temperatures.

Many unsaturated fats are contained in various types of cooking oils and other foods. These fats are collectively referred to as “healthy fats” because they do not appear to promote the formation of atherosclerosis, a waxy plaque that can build up in arteries. There are two types of unsaturated fat: monounsaturated fat and polyunsaturated fat. Although they differ slightly and the foods that they are in, including both types of fat in your diet can help improve your heart health and your lipid profile.

Monounsaturated Fats

Monounsaturated fats have only one double bond in their molecular structure. There are several healthy foods that contain monounsaturated fats, including:

• Certain cooking oils – such as olive oil, sesame oil, and canola oil
• Peanut butter
• Certain nuts – such as peanuts and cashews
• Avocados
• Olives
• Sesame seeds
• Some healthy spreads that are labeled “ high oleic”

Polyunsaturated Fats

Polyunsaturated fats differ from monounsaturated fats in that they have more than one double bond in their structure.

Foods that are high in polyunsaturated fats include:

• Certain seeds – such as sunflower seeds and pumpkin seeds
• Certain cooking oils – including corn oil, safflower oil, and soybean oil
• Certain nuts – such as pine nuts and walnuts

A certain type of polyunsaturated fats, omega-3 fats, have especially been studied regarding their effect on heart health and their ability to lower lipid levels. Studies have shown that omega-3 fats can lower triglyceride levels and slightly increase HDL levels. The following foods contain this specific type of polyunsaturated fat:

• Fatty fish – including salmon, mackerel, herring, and tuna
• Certain seeds – such as flax seeds and chia seeds
• Walnuts
• Algae

Which Fats Should You Consume?

Despite the slight differences in their chemical structure, both types of unsaturated fat have been linked to promoting heart health by improving your lipid profile, including modestly increasing HDL cholesterol and helping to lower LDL cholesterol and triglyceride levels. Studies have shown that replacing saturated fat and trans fats with foods containing mainly monounsaturated and polyunsaturated fats can help to protect you against heart disease. There is more evidence regarding this with polyunsaturated fats than monounsaturated fats.

Because of this, the American Heart Association recommends that you replace foods in your diet containing saturated fats and trans fats with foods higher in monounsaturated and polyunsaturated fats – including foods such as fatty fish, nuts, seeds, and oils. Fat intake should not consist of more than between 25 and 35% of the total calories you consume each day.

Although foods high in monounsaturated and saturated fats are heart-healthy, you should not go overboard in consuming them. Their calorie content is still high and could tack on calories to your diet if you consume too many of these foods.

Sources:

American Heart Association: Knowing Your Fats. Link: http://www.heart.org/HEARTORG/Conditions/Cholesterol/PreventionTreatmentofHighCholesterol/Know-Your-Fats_UCM_305628_Article.jsp#.V0e9spErKM8.

Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (PDF), July 2004, The National Institutes of Health: The National Heart, Lung, and Blood Institute.

Whitney EN and SR Rolfes. Understanding Nutrition, 14ed. Wadsworth Publishing 2015.