Why Do They Say Canola Oil is Not Good for You? Unpacking the Controversy

January 8, 2026 •

4 min read

The first version of food-grade canola oil was developed in Canada in the 1970s from rapeseed, which previously contained harmful erucic acid. Today, many people question if canola oil is not good for you due to modern processing methods, genetic modification, and fatty acid composition.

Quick Summary

Canola oil's negative reputation stems from its extensive chemical processing, frequent genetic modification, and an unbalanced omega-6 to omega-3 ratio, sparking debate over its health effects.

Key Points

Extensive Processing: Standard canola oil is a 'refined, bleached, and deodorized' (RBD) oil, often extracted with chemical solvents like hexane.
Oxidative Instability: High heat and light can cause canola's polyunsaturated fats to oxidize, potentially forming harmful compounds and trans fats, especially when repeatedly heated.
Inflammatory Omega Ratio: The high omega-6 content in canola oil contributes to a skewed omega-6 to omega-3 ratio in the typical Western diet, which is linked to increased inflammation.
Genetic Modification Concerns: The vast majority of canola oil comes from genetically engineered crops, which many consumers seek to avoid for environmental or health reasons.
Animal Study Red Flags: Some animal studies suggest potential links between canola oil consumption and negative outcomes such as increased inflammation, memory impairment, and higher blood pressure.
Better Alternatives Exist: Less refined oils like extra virgin olive oil and avocado oil offer similar cooking properties but with better nutrient profiles and greater stability.

The Roots of the Canola Oil Controversy

For decades, canola oil has been marketed as a heart-healthy cooking oil due to its low saturated fat content and high levels of monounsaturated fats. However, a significant public backlash has emerged, driven by concerns over how it is produced and its potential health impacts. The central question of why do they say canola oil is not good for you is rooted in several key points, including its highly refined nature, a potentially inflammatory omega fatty acid profile, and the prevalence of genetically modified crops.

Canola Oil's Highly Refined and Processed Nature

The most common canola oil found on grocery store shelves is a highly refined, bleached, and deodorized (RBD) oil. This extensive industrial process is a major source of concern for critics. The manufacturing process involves several steps that can degrade the oil and its nutrients:

Extraction: The oil is extracted from the seeds using a chemical solvent, most commonly hexane. While most residual solvent is removed, the use of such a chemical raises alarms for some consumers.
High-Heat Treatment: The seeds and oil are subjected to high temperatures during processing. This high heat can damage the delicate polyunsaturated fats, including the beneficial omega-3s, and destroy antioxidants and other nutrients.
Bleaching and Deodorizing: To create the neutral color and flavor many cooks prefer, the oil is bleached and then deodorized. This step can further strip the oil of beneficial compounds and potentially create harmful trans fats, especially if it is partially hydrogenated.

The Omega-6 to Omega-3 Imbalance and Inflammation

Canola oil contains both omega-6 (linoleic acid) and omega-3 (alpha-linolenic acid or ALA) polyunsaturated fatty acids. While promoters tout a favorable 2:1 ratio, the actual effect on health is more complex. The modern Western diet is already excessively high in omega-6 fatty acids from a wide variety of processed foods. While both are essential, a disproportionately high intake of omega-6s relative to omega-3s is linked to increased inflammation, a risk factor for several chronic diseases. Because canola oil is so prevalent in processed foods and restaurant cooking, it is considered a significant contributor to this imbalanced dietary intake.

Concerns Over Genetic Modification (GMO)

Another major reason people view canola oil with skepticism is that over 90% of canola crops in North America are genetically modified (GMO). These plants are engineered to be resistant to herbicides like glyphosate. Critics raise several issues with this:

Increased Herbicide Use: Herbicide-resistant crops allow for increased spraying of chemicals on the plants, which could potentially result in herbicide residues in the final food product.
Environmental Impact: There are concerns about the environmental effects of widespread GMO monocropping and herbicide use.
Consumer Preference: Many consumers prefer to avoid GMO foods for personal or ethical reasons, regardless of whether health risks have been definitively proven.

Negative Findings from Animal Studies

Several animal studies have raised specific red flags regarding canola oil consumption, though animal studies do not always translate to human health outcomes. Some findings have included:

In one rat study, a canola oil diet was associated with a decreased lifespan and increased blood pressure compared to a soybean oil diet.
Another mouse study found that chronic canola oil consumption negatively impacted memory and caused significant weight gain.
Heated canola oil has been shown to increase inflammatory markers in rats.

Canola Oil vs. Healthier Alternatives: A Comparison

To better understand the controversy, it is helpful to compare standard refined canola oil with other popular cooking oils. The table below highlights key differences.


Feature	Refined Canola Oil	Extra Virgin Olive Oil	Avocado Oil
Processing	Highly refined with heat and solvents	Minimally processed, expeller-pressed	Minimally processed, expeller-pressed
GMO Status	Over 90% is GMO in North America	Non-GMO	Non-GMO
Nutrients	Low antioxidant content due to processing	Rich in antioxidants and polyphenols	Rich in vitamin E and antioxidants
Omega-6:3 Ratio	Typically 2:1	~9:1	~12:1
Heat Stability	High smoke point, but polyunsaturated fats oxidize	Lower smoke point, excellent heat stability due to monounsaturated fat and antioxidants	Very high smoke point, excellent stability

Alternatives and Considerations

For those looking to reduce or replace canola oil, several alternatives offer superior health profiles, different flavor characteristics, and stability. Some options include:

Extra Virgin Olive Oil: Ideal for dressings and lower-heat cooking, packed with monounsaturated fats and antioxidants.
Avocado Oil: Excellent for high-heat cooking like frying and searing due to its high smoke point and stability.
Coconut Oil: Best for baking and medium-heat cooking; note its high saturated fat content and distinct flavor.
Nut Oils (e.g., Walnut Oil): Offer a rich flavor and a good source of omega-3s, but are best for low-heat applications due to low smoke points.

Conclusion

The concerns raised about canola oil, particularly regarding its extensive refining process, potential for oxidation and trans fat formation when heated, high omega-6 content, and GMO origins, lead many people to question its health benefits. While some industry-funded studies have presented it as a healthy option, and it contains beneficial ALA omega-3s, critics point to the potential negative effects of inflammation and oxidative stress linked to its processing and composition. For those seeking to minimize processed food ingredients and reduce dietary omega-6, alternative oils like extra virgin olive oil and avocado oil offer compelling, less-processed options. Ultimately, a balanced dietary approach that favors minimally processed fats over heavily refined oils is key to good health, and the public's skepticism surrounding canola oil reflects a growing desire for transparency in food production.

For further reading on the complex research surrounding this oil, you can visit Healthline's detailed analysis.

Frequently Asked Questions

No, canola oil is not banned in Europe, but its quality and content are highly regulated by the European Food Safety Authority. Historically, some rapeseed varieties were restricted due to high erucic acid, but modern, low-acid canola oil is permitted and controlled.

Modern food-grade canola oil is bred to contain less than 2% erucic acid, an amount considered safe by regulatory bodies. The original rapeseed oil from which canola was developed did have high levels of erucic acid, which was the basis for earlier health concerns.

Organic and expeller-pressed canola oils are less processed and avoid chemical extraction, which is a major concern with standard varieties. While they are a better option for those concerned with chemicals and GMOs, they still have an omega-6 to omega-3 ratio that could contribute to an inflammatory diet.

The refining process, which uses high heat, bleaching, and deodorizing, can significantly decrease the oil's nutritional value. This process strips away beneficial compounds like antioxidants and essential fatty acids, leaving a neutral-flavored oil with a higher risk of oxidation.

Yes, especially with repeated, high-heat cooking like deep-frying. The unsaturated fats in canola oil are susceptible to oxidation and isomerization at high temperatures, which can lead to the formation of trans fats and other potentially harmful compounds.

While omega-6 fats are essential, the standard Western diet provides an overabundance of them, creating an imbalance with omega-3 fats. Canola oil, while having a relatively moderate ratio, is so prevalent in processed foods that it contributes significantly to this imbalance, which promotes inflammation in the body.

For low-heat cooking and dressings, extra virgin olive oil is a great choice. For high-heat cooking, avocado oil offers a very high smoke point and excellent stability. Other options include nut oils for flavor in dressings or coconut oil for baking.