There's a lot of controversy surrounding fats and cooking oil. Some experts say that you should replace saturated fats like butter with unsaturated fats like canola oil. Others, like the researchers involved in a September 2018 report that was published in Current Nutrition Reports, say that saturated fat isn't as big of a problem as people were led to believe.
But when it comes to unsaturated fats, many experts agree that you should include more of them in your diet. So what about when the question comes down to the health difference between canola oil and olive oil, two unsaturated fats that are both touted as a healthy option?
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Although canola oil and olive oil are both rich in unsaturated fats, olive oil may be the healthier option. Canola oil is higher in a specific type of omega-6 fatty acid, called linoleic acid, that may contribute to chronic inflammation when consumed in excess. Canola oil is also typically extracted using a refining process that destroys important nutrients and creates trans fats, while olive oil isn't.
How Canola Oil Is Made
Canola oil is extracted from the seeds of the canola plant, which is actually a rapeseed plant that's been modified to contain lower levels of a toxin called erucic acid. For most commercial brands, the oil is extracted by crushing the seeds from the plant and then dissolving them in solvents, like hexane. After extraction, canola oil is refined and filtered.
According to a report in PLoS One in December 2018, this refining process doesn't just remove important nutrients, like vitamin E, beta-carotene and chlorophyll, it also creates hydrogenated fats, called trans fats, that can increase your risk of heart disease, certain types of cancers and free radical damage.
The same report mentions that although they are less common, cold-pressed canola oils don't undergo the same refining process and, as a result, they're rich in fat-soluble vitamins, beta-carotene, chlorophyll and other essential fatty acids.
How Olive Oil Is Made
Extra-virgin olive oil, which is the top of the line in quality when it comes to olive oil, is made by mechanically pressing ripe olives to extract their oils. With true extra-virgin olive oils, there's no heat or chemical solvents involved in the process. Because of this, olive oil is rich in a class of antioxidants called phenols, while canola is not since it loses the phenols during processing.
These phenols in olive oil help protect the artery walls from damage, reducing your risk of developing heart disease. They also keep your blood healthy and provide general anti-inflammatory benefits.
Keep in mind that not all olive oils are the same. You may see light olive oil or extra light olive oil in addition to extra-virgin. These types of oils are generally highly processed and contain a mixture of olive oil and other less expensive oils, like soybean oil. Unlike extra-virgin olive oil, highly processed olive oils don't have that same rich content of antioxidants.
Canola Oil vs. Olive Oil
All vegetable oils contain a mixture of monounsaturated, polyunsaturated and saturated fats. The difference between canola oil and olive oil, aside from what they're made from, is the percentage of each type of fat that it contains. Canola oil contains 62 percent monounsaturated fat, 31 percent polyunsaturated fat and 7 percent saturated fat. Olive oil is composed of 78 percent monounsaturated fat, 8 percent polyunsaturated fat and 14 percent saturated fat.
Many health experts claim that polyunsaturated fatty acids, like omega-3 and omega-6 fatty acids, lower cholesterol and reduce the risk of heart disease, but an April 2014 review in the Canadian Medical Association Journal reported that these health claims may not be warranted, especially in oils that are higher in an omega-6 fatty acid called linoleic acid than they are in an omega-3 fatty acid called alpha-linolenic acid.
Omega Fatty Acids Ratio
There's a lot of focus on the amount of omega fatty acids in the diet, but what's equally important is the ratio of omega-6 fatty acids to omega-3 fatty acids. According to a review published in BMJ in January 2016, eating a lot of omega-6 fatty acids can contribute to inflammation and an increase in fat tissue. The report also notes that a typical Western diet contains a 16:1 ratio of omega-6 to omega-3 fatty acids.
Another report published in Nutrients in 2016 connects a high intake of omega-6 fatty acids to both leptin resistance and insulin resistance, a precursor to type 2 diabetes.
While both canola oil and olive oil contain omega 6 fatty acids, canola oil contains greater amounts since it's made up of 31 percent polyunsaturated fats, compared to olive oil's 8 percent. While periodically including canola oil in your diet shouldn't be an issue for most people, it presents a problem when you're eating it in large amounts in addition to lots of other sources of excessive omega-6 fatty acids, like processed foods.
The Best Cooking Oils
When it comes to cooking, all oils aren't created equally. Some oils can withstand high-heat cooking, while others break down when exposed to too much heat. The temperature at which an oil breaks down during heat is called the smoke point. If you heat an oil past its smoke point, it doesn't just affect the flavor of the oil, it can also produce byproducts that can be toxic to your health.
Olive oil's smoke point is relatively low. With a smoke point between 212 F and 300 F, olive oil is best used for sautéing over medium heat or baking. On the other hand, canola oil has a relatively high smoke point of more than 375 F. Because of this, it wins the canola oil vs. olive oil battle when it comes to grilling, frying or other high-heat cooking.
Other high-heat cooking oils include:
- Avocado oil
- Peanut oil
- Sesame oil
- Coconut oil
- Harvard T.H. Chan School of Public Health: "Ask the Expert: Concerns About Canola Oil"
- Providence Health and Services: "Ask the Dietitian: How to Choose the Right Oil for Different Cooking Temperatures"
- Berkeley Wellness: "Canola Oil Myths and Truths"
- Iowa State University Extension and Outreach: "Vegetable Oils – Comparison, Cost, and Nutrition"
- PLoS One: "Characterization of Canola Oil Extracted by Different Methods Using Fluorescence Spectroscopy"
- Harvard Health Publishing: "Is Extra-Virgin Olive Oil Healthy?"
- Harvard Health Publishing: "On Call: Olive Oil and Health"
- Current Nutrition Reports: "Saturated Fat: Part of a Healthy Diet"
- BMJ: "The Importance of a Balanced ω-6 to ω-3 Ratio in the Prevention and Management of Obesity"
- Canadian Medical Association Journal: "Omega-6 Polyunsaturated Fatty Acids: Is a Broad Cholesterol-Lowering Health Claim Appropriate?"
- Today's Dietitian: "Heart-Healthy Oils: They're Not All Created Equal"
- Nutrients: "An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity"