Are You Cooking with Toxic Oils?

When it comes to cooking, many of us are conditioned to grab some type of oil and cover the bottom of the pan to prevent food from sticking or burning. However, what the majority of people do not realize is that there is a right and wrong oil for different cooking needs.

Oil is very good at transferring heat; it is able to efficiently and evenly distribute the pan’s heat. Therefore, utilizing oil helps ensure that the food is being cooked thoroughly and at the same temperature. Vegetable oils are also used because of their nutrient content. They are rich in Omega 3 and 6, which are essential fatty acids for your body; they help with general biological function, structure, and energy. Prior to vegetable oils, the standard method was to use animal lard/fat to cook, however lard was not as readily available as plants.


Cooking with oils is a commonality between many cultures dating back as early as 3000 B.C. Depending on location, different cultures utilized diverse sources to generate their cooking oils. Soy oil was commonly found in Chinese and Japanese cultures, whereas olive oil was dominant in southern European regions. African cultures utilized palm kernels and coconut meat to extract oil from, while indigenous American cultures used sunflower seeds and peanuts.

To create oil, early cultures had to exploit different heating techniques to extract the oil. A common method was to roast the seeds/nuts, crush them, and then boil the beaten seeds. Once boiled, a layer of oil would appear on the surface of the water which would be extracted for use.

As time evolved, these methods improved to increase the output of oil as its demand increased. Manufacturing equipment, such as a hydraulic press and a roll mill, were used in this process to aid with better grinding and pressing of the plant seeds to expand the overall oil extraction process.

In the late 1800’s, scientists started experimenting with a more efficient extraction process. Solvents, such as benzene, started to be sprayed onto the seeds to aid the extraction of the oil. Scientists were now able to take different varieties of seeds and nuts to generate oil that would not have been made from natural extraction techniques. Cottonseed oil is a very good example of this; farmers could now take the waste seeds from the plant extraction and use them to create oil.

Though it may seem that the process for extracting these oils has improved, the actual oil recovery has surprisingly decreased. Traditional methods yielded about 10% of the actual oil available whereas solvent extraction can only extract 0.5-2% of the available oil.

The Way Oil is Created Matters

Currently, there are two distinct methods for creating cooking oils; cold-pressed and refined. Refined oils are ones that have been treated with heat and utilize the solvent extraction technique. These oils are made to satisfy demand instead of nutritional needs; due to low yield of oil being produced, synthetic chemicals provide a filler. During the refining process, the natural nutrients are killed and mutated by the various synthetic chemicals used such as bleach, hexane, and phosphate. The process also uses heats of up to 500 ° F which can cause the formation of trans-fats and toxic chemicals. All these factors play an important role in the final composition of the oil.

Cold-pressing is a technique based off traditional pressing methods. No heat is used in this method and therefore minimizes the processing of the oil and maximizes the nutrient benefits. This is done to create light and flavorful oils. When oil is refined, taste, color, and odor are diminished, therefore low-quality seeds can be used.

Below is a list of commonly refined oils and known cold-pressed oils

Cold-Pressed Refined
Avocado Canola
Coconut Corn
Flaxseed Safflower
Olive Soybean
Peanut Sunflower
Sesame Seed Vegetable
**Some refined oils can be made cold-pressed/unprocessed but they are not as common

Temperature Is Key

When oil is heated up, it can release toxic particles into the air. Many carcinogenic chemicals have been found in the fumes of some cooking oils, but most prevalent are aldehydes. Aldehydes are formed when the fatty acids in oils are broken down by overheating. When broken down, they become free radicals - toxic byproducts - released into the air, which we can inhale. When introduced to the body, free radicals cause a disruption in cell membranes damaging cell linings in the gut, blood vessels, and more. These chemicals have shown the potential to cause damage to your genes.

The formation of aldehydes is dictated by the composition of the oil and the temperature at which the oil is heated; therefore, it is important to know which oil to use for different cooking techniques to minimize the release of free radicals into the air. But how do you know if your oil is right for your cooking style?

Each oil has a defined smoke point - the temperature in which the oil starts to smoke and burn. If you continue to cook with an oil after it reaches its smoke point, beneficial nutrients and phytochemicals are destroyed and free radicals are formed. When cooking, make sure to use oils with higher smoke points and a low concentration of unsaturated fatty acids to reduce your toxic exposure.

Here is a list of cooking methods and their respective temperatures:

Method Temperatures
Cold-plated Less Than 300 ° F
Baking 300-400 ° F
Sautéing 400-450 ° F
Frying Greater Than 450 ° F
*These temperatures indicate a range for the typical temperature of cooking methods. When cooking, use this table to match the proper oil for your cooking method to prevent surpassing the smoke point.

Here is a list of healthy, cold-pressed oils, their smoke points, and ideal cooking methods:

Oil Smoke Point Best Used
Flaxseed Oil 225 ° F Dressings, smoothies, cold-plated
Walnut Oil 320 ° F Dressings, cold-plated
Coconut Oil 350 ° F Baking, sautéing
Grapeseed Oil 400 ° F Sautéing, frying, baking, dressing
Extra Virgin Olive Oil 410 ° F Sautéing, frying
Almond Oil 430 ° F Sautéing, frying
Peanut Oil 450 ° F Searing, deep-frying, pan-frying, sautéing, roasting, grilling, baking, dressings
Light Olive Oil 470 ° F Searing, frying, grilling, roasting, baking, dressings
Avocado Oil 520 ° F Searing, frying, grilling, roasting, baking, dressings

Key Points

When it comes to cooking, knowing what you are cooking with is very important for your overall health and wellbeing.
  • Make sure to cook with and eat cold-pressed oils. This will ensure you are receiving all the natural nutrients from the specific seeds/nuts.
  • Make sure that when you do cook with oil, you use the right oil for your cooking technique. This will reduce your risk of exposing yourself to toxic byproducts due to overheating.

Interested in improving your health and well-being? Learn more about how our Healthoscopy™ Solution can help you!

Cooking Oil, Staff ( 

Effects of cooking method, cooking oil, and food type on aldehyde emissions in cooking oil fumes, Peng, C-Y (Department of Public Health, Kaohsiung Medical University, Kaohsiung 80708, Taiwan) 

Electrophilic Derivatives of Omega-3 Fatty Acids for the Cure and Prevention of Neurodegenerative Disorders, Cipollina, C (Fondazione Ri.Med, Palermo, Italy; Istituto di Biomedicina e Immunologia Molecolare (IBIM), Consiglio Nazionale delle Ricerche, Palermo, Italy) 
page 499

The Shocking Origin of Vegetable Oil — Garbage, Fung, J (Intensive Dietary Management Program) 

What is smoke point and does it matter when cooking with oil?, Beck, Leslie (Medisys Clinic, Toronto) 

Click here to see your activities