Maybe like so many others, you have no idea what cooking oil to use to benefit your health. You know olive oil is good, but is it actually good for cooking food at high temperatures?

The most important factors to consider when choosing a good cooking oil is its smoke point and whether it is heavily processed.

Connection between Coeliac and Thyroid Disease

What is the Smoke Point

The smoke point of a fat or oil is the temperature it needs to reach before it burns and becomes damaged. This can vary significantly amongst oils, even between olive oils and it is therefore important that you understand the smoke point of your preferred oils. Understanding the smoke point enables you to choose the right oil for frying, baking, dressing, etc. The table below shows the smoke point in celsius of some of the most frequently used oils.

Oil Smoking point in Celsius Cooking suitability
Avocado Oil 271 High-heat cooking, low-heat cooking, dressing
Ghee 249 High-heat cooking, baking
Refined Olive Oil 240 High-heat cooking, low-heat cooking, dressing. Cooked at a high heat olive oil will lose its flavour
Refined Coconut Oil 232 High-heat cooking, baking, sauteing
Sesame Oil 232 Dressings and loaded with antioxidants
Macadamia Nut Oil 210 Low-heat cooking, dressings
Duck Fat 190 High-heat cooking
Lard 190 High-heat cooking. Always opt for substainably-raised
Unrefined Olive Oil 160 Low-heat cooking, dressings
Unrefined Butter 149 High-heat cooking, baking
Connection between Coeliac and Thyroid Disease

Processed Oils

Unfortunately, many processed oils and fats have a high smoke point. So, whilst your oil might have a really high smoke point, the fact that it is heavily processed might be counteracting the nutrients and benefits that you were hoping to obtain. Many processed foods are high in chemicals as they often use chemicals to refine the oil.

A good example is canola oil, which is made from rapeseed, but in order to remove the oil from the rapeseed they use a petroleum solvent. This begs the question: How much do we really understand about our food chain?

It is worrying to know that most of the oils used in salad dressings, condiments, mayonnaise, artificial cheese, cakes, biscuits and snack foods are processed. Many of these oils may be made from GMO crops and laden with chemicals and pesticides. The reality is the our entire food chain is built on these oils.

Good examples of processed oils and fats to avoid that can cause inflammation are:

  • Canola oil (rapeseed oil)
  • Corn oil
  • Cottonseed oil
  • Grapeseed oil
  • Safflower oil
  • Soybean oil
  • Sunflower oil (all my food as a child was cooked with this!)
  • Vegetable shortening

Common Descriptors

Before choosing the best oil for you and your family, it is important to understand the common descriptors found on the packaging.

Refined – these oils are extracted and treated with chemicals and heat and as a result many of the beneficial properties are lost. Refined oils are generally more stable and therefore better for baking and cooking at high temperatures. Examples include vegetable spray or light oils and refined olive oil.

Unrefined – these oils are extracted by cold pressing the oils out of the vegetables. They are not treated with chemicals or heat and as a result offer all the nutritional properties of the plant. Good examples include virgin and extra-virgin olive oil.

Extra-Virgin – these are the oils taken from the first cold pressing of the plant source, which means these oils can be fragile. These oils are perfect for salads, drizzling and dipping.

Virgin – oils from the second cold pressing of the plant source. These oils are also fragile and are best enjoyed on salads, in dips and low-heat cooking.

Pure – these oils come from the first batch of cold pressing but may be treated with chemicals and/or heat to remove impurities before it gets bottled.

Cold-Pressed – oils that are removed from the plant source by the force of pressure. You are not allowed to use any chemicals or heat to extract the oil. This therefore means that it provides the full nutritional benefits of the plant source.

How to choose and store your oil

  1. Always aim to purchase your oil in a dark coloured glass bottle. Remember oils and fats can oxidise when they come into contact with light, heat, air or plastics.
  2. Always make sure your oil has been sealed well as any air will damage the oil and can make it rancid.
  3. Choose a different oil for your salad dressings and cooking and opt for something like coconut or avocado oil that has a higher smoke point for cooking.
  4. Avoid storing your oils by the stove or any other heat sources as this can damage your oil. Instead, store your oils in a cupboard or pantry to prevent it from becoming oxidised.

Why the oil you choose can impact your thyroid

Processed oils are typically high in trans fats and omega 6. Now don’t get me wrong, we actually need good levels of omega 6 fatty acids in our diet, but what’s important to consider is the ratio between omega 6 and omega 3. An optimal omega 6:3 ratio should be around 3:1, but since the traditional western diet is loaded with refined and processed foods high in omega 6 foods, the average person’s ratio is now somewhere between 15:1 and 20:1 and in many cases even higher!

Omega-6 fatty acids are very sensitive and can easily oxidise when exposed to natural light and also in the body’s cells.  These oxidised cells can cause inflammation, which can lead to hypothyroidism, Hashimoto’s, other autoimmune diseases, cancer, cardiovascular disease, Alzheimer’s and more. Any pro inflammatory food, if consumed on a regular basis is going to negatively impact your health.

It is therefore important that you pay close attention to the oils you use, really work on optimising your omega 3:6 ratio by including cold water fatty fish into your diet. Eat real foods and be mindful that nut flours are high in omega-6 fatty acids and therefore have the potential to oxidise at high temperatures. Opt for coconut or cassava flour instead.

If you want to understand what your own omega 3:6 ratio is then you might find this video helpful. I have been using their testing and oil for a while and love the results that my clients get in restoring their omega 3:6 ratio. If you want to understand more, then get in touch.

Connection between Coeliac and Thyroid Disease