The Differences Between Monounsaturated and Polyunsaturated Fats

Unsaturated fats come in two types—monounsaturated fat and polyunsaturated fat. Although they differ slightly, including both types in your diet can help improve your heart health and blood cholesterol levels.

This article discusses the two types of unsaturated fats, including why they're good for you, what foods have them, and how they differ from saturated fats.

What Are Unsaturated Fats?

Unsaturated fats are considered healthy fats. Research has found they improve cholesterol, decrease inflammation, and stabilize heart rhythms.

They are made of carbon atom chains that don't have many surrounding hydrogen atoms. Because of their structure, they're usually liquid at room temperature.

In contrast, saturated fats are "saturated" with hydrogen atoms, meaning they have a lot of hydrogen surrounding the carbon atoms. Saturated fats are typically solid at room temperature.

Saturated fats have traditionally been thought to increase your risk of cardiovascular disease because they increase bad cholesterol (LDL). However, research is showing that the link between saturated fat and cardiovascular disease may not be as clear as once thought. An analysis of 21 studies found there wasn't enough evidence that saturated fat by itself increases the risk of heart disease.

While research is still ongoing, the American Heart Association (AHA) recommends eating foods with unsaturated fat instead of saturated fat when possible. That's because studies have found that replacing saturated fats with unsaturated fats can decrease the risk of heart disease.

In contrast, replacing saturated fat with carbohydrates did not show the same reduction in heart disease risk, and in some cases made it worse.

According to the AHA, both monounsaturated and polyunsaturated fats can lower rates of cardiovascular disease and all causes of mortality. These fats also help to decrease bad cholesterol and triglyceride levels.

Monounsaturated Fats

Monounsaturated fats have only one carbon-to-carbon double bond in their molecular structure. They help lower bad (LDL) cholesterol levels and help in maintaining the overall health of cells. 

Several healthy foods contain monounsaturated fats, including:

• Cooking oils, such as 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 have more than one double bond in their carbon structure. Much like monounsaturated fats, polyunsaturated fats can help lower unhealthy LDL cholesterol. 

Polyunsaturated fats are essential for your body's functions, including building cell membranes and blood clotting. Your body can't make polyunsaturated fats, so you have to get them from food.

There are two main types of polyunsaturated fats: omega-3 and omega-6 fatty acids. Your body needs both of these 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

Omega-3 Fats

A certain type of polyunsaturated fat, omega-3 fat, has been studied regarding its effects on heart health.

Research shows omega-3 fats can lower triglyceride levels and slightly increase HDL (good cholesterol) levels. A 2016 study found eating fish high in omega-3 fatty acids at least twice a week significantly decreases blood triglyceride levels.

Omega-3 fats in fish have also been found to lower your risk of abnormal heart rhythms, which can lead to sudden death.

The following foods contain this specific type of polyunsaturated fat:

• Fatty fish, including salmon, mackerel, herring, sardines, and tuna
• Seeds, including flax seeds and chia seeds
• Walnuts
• Algae (e.g., seaweed, spirulina, nori)

The American Heart Association recommends eating two 3.5-ounce servings of non-fried fish every week to get the benefits of omega-3 fats.

Summary

Both monounsaturated fats and polyunsaturated fats have heart-healthy benefits including decreasing inflammation and improving cholesterol. They've been found to decrease cardiovascular disease when they replace saturated fat in your diet.

A Word From Verywell

You may tend to think of fats as being bad for you. However, your body needs some of the fat that we get from food, particularly healthy fats like unsaturated fats. While the jury is still out on saturated fats, most doctors still recommend replacing them with unsaturated fats when possible.

Your physician or dietitian can help answer your questions about the types of fats to include in your diet.