When it comes to cooking, many people opt for what they believe are the healthiest oils—like avocado oil and olive oil. These oils are praised for their heart-healthy fats, antioxidants, and high smoke points, making them go-to choices in the kitchen. But what if cooking with these oils diminishes their benefits and, worse yet, turns them toxic? In this in-depth look, we’ll explore the science behind cooking oils, why high heat might undermine your healthy intentions, and what you should use instead.

The Science of Oil Degradation

Understanding Oxidation: When oils oxidize, they lose their beneficial properties and produce free radicals—unstable molecules that can damage cells and contribute to inflammation and chronic diseases. Even though avocado and olive oils have high smoke points (the temperature at which they begin to smoke and break down visibly), they still oxidize well before reaching these temperatures. This means that your oil could already produce harmful byproducts even if you’re not seeing smoke.^[1]

The Loss of Nutritional Value: One of the reasons avocado and olive oils are so highly regarded is their content of antioxidants and polyphenols, which have been shown to combat oxidative stress and reduce inflammation. However, these compounds are highly sensitive to heat. When exposed to high temperatures, antioxidants like vitamin E and beneficial polyphenols break down, stripping the oil of much of its health-promoting potential. Essentially, by cooking with these oils, you’re losing the very nutrients that make them beneficial in the first place.^[1]

Formation of Toxic Compounds: Another concern with heating oils is the formation of toxic compounds such as aldehydes, ketones, and lipid peroxides. These substances are byproducts of fat oxidation and have been linked to a variety of health issues, including neurodegenerative diseases, heart disease, and cancer. The longer and hotter you cook your oils, the more harmful compounds are produced, potentially turning your healthy meal into a toxic one.^[2]

The Perils of Seed Oils

While avocado and olive oils degrade under heat, seed oils like canola, soybean, and sunflower oil are even more problematic. These oils are often promoted as heart-healthy due to their high polyunsaturated fat content, but polyunsaturated fats are highly unstable and prone to oxidation, especially when heated.

The Omega-6 Fat Dilemma: Seed oils are rich in omega-6 fatty acids, a type of polyunsaturated fat that is essential in small amounts but can be harmful when consumed in excess. A diet high in omega-6 fatty acids, especially when oxidized through cooking, can promote inflammation, a key driver of many chronic diseases. The imbalance of omega-6 to omega-3 fatty acids in the typical modern diet is a significant concern. When seed oils like canola or soybean oil are heated, the omega-6 fatty acids within them oxidize rapidly, creating harmful byproducts that contribute to systemic inflammation. This imbalance can lead to an increased risk of heart disease, diabetes, and other chronic conditions.

Industrial Processing Woes: Seed oils are typically produced through industrial processes that involve high heat and chemical solvents. These methods strip the oils of natural nutrients and introduce impurities, making them more prone to oxidation when you cook with them. The result is an oil that is nutritionally depleted and potentially harmful right out of the bottle. When these oils are further exposed to high cooking temperatures, they become a source of toxic compounds you want to avoid.

Choosing the Right Oils for Cooking: A Crucial Decision for Your Health

Given the risks associated with heating more delicate oils, it is crucial to choose fats that can withstand high temperatures without degrading. Saturated fats, which are more stable under heat, are your best bet for cooking.

Organic Ghee: Ghee, a type of clarified butter, is ideal for cooking at high temperatures. It has a high smoke point (around 485°F or 250°C) and is rich in butyrate, a short-chain fatty acid that supports gut health. Since ghee is free of the milk solids that can burn in regular butter, it remains stable and doesn’t produce harmful compounds when heated.^[4]

Organic Coconut Oil: Due to its high saturated fat content, coconut oil is another excellent option for high-heat cooking. These fats are much more oxidation-resistant than the polyunsaturated or monounsaturated fats in other oils. Coconut oil’s medium-chain triglycerides (MCTs) provide a quick energy source and have been linked to various health benefits, including improved brain function.^[5]

Grass-Fed Butter: While not as stable as ghee, grass-fed butter can still cook at lower temperatures. It’s rich in fat-soluble vitamins like A, D, and K2 and contains conjugated linoleic acid (CLA), which is associated with reduced body fat and improved metabolic health. However, be cautious not to overheat butter—once it turns brown, it oxidizes and loses its nutritional benefits.

Animal Fats: Camel Fat and Beef Tallow: For those looking to diversify their cooking fats, animal fats like camel fat and beef tallow are highly stable under heat. These fats are rich in saturated fatty acids, which remain intact even when exposed to high temperatures. They also impart a rich, savory flavor to dishes, making them a delicious and safe option for cooking.^[5]

Making the Most of Healthy Oils

Reassuringly Healthy: Making the Most of Avocado and Olive Oils

Use as a Finishing Oil: One of the best ways to preserve the nutrients in avocado and olive oils is to use them as a finishing touch. Drizzle them over salads, cooked vegetables, or grilled meats to add flavor and nutrition without subjecting them to heat.

Cold Applications: Avocado and olive oils shine in cold dishes. They’re perfect for making salad dressings, dips, and marinades. If you’re marinating something that will be cooked, simply add the oil after cooking to maintain its health benefits.

Low-Heat Cooking: If you want to cook with these oils, keep the heat low. Gentle sautéing or simmering can minimize the risk of oxidation, allowing you to enjoy the flavor and some of the nutritional benefits without compromising your health.

Conclusion: Rethink Your Cooking Oil Strategy for Better Health

The oils you choose for cooking can significantly impact the nutritional quality of your meals. By understanding the risks associated with heating delicate oils like avocado and olive oil and selecting more stable fats for high-temperature cooking, you can protect your health while enjoying delicious, nutrient-rich food. Stick to saturated fats like ghee, coconut, and animal fats for cooking, and reserve your avocado and olive oils for cold dishes or finishing touches. With this approach, you’ll enhance the flavor of your meals and safeguard your well-being in the long run.

References:

1. Resende, Lívia Maria Braga, et al. “Changes in Quality and Phytochemical Contents of Avocado Oil under Different Temperatures.” Journal of Food Science and Technology, vol. 56, no. 1, Jan. 2019, pp. 401–08. PubMed Central.
2. Pizzimenti, Stefania, et al. “Interaction of Aldehydes Derived from Lipid Peroxidation and Membrane Proteins.” Frontiers in Physiology, vol. 4, Sept. 2013, p. 242. PubMed Central.
3. Liu, Wen, et al. “Comparison of the Effects of Monounsaturated Fatty Acids and Polyunsaturated Fatty Acids on Liver Lipid Disorders in Obese Mice.” Nutrients, vol. 15, no. 14, July 2023, p. 3200. PubMed Central.
4. Kataria, Deepshikha, and Gurmeet Singh. “Health Benefits of Ghee: Review of Ayurveda and Modern Science Perspectives.” Journal of Ayurveda and Integrative Medicine, vol. 15, no. 1, 2024, p. 100819. PubMed Central.
5. Denke, M. A. “Role of Beef and Beef Tallow, an Enriched Source of Stearic Acid, in a Cholesterol-Lowering Diet.” The American Journal of Clinical Nutrition, vol. 60, no. 6 Suppl, Dec. 1994, pp. 1044S-1049S. PubMed