Q: “What happens to an oil when we add heat for cooking?”
A: Oxidation and a loss of nutrients. This does not mean you shouldn’t cook with your oils, but it does suggest to do so mindfully.
All natural oils go through an oxidation process over time and through exposure to inappropriate light, air, and temperature.
It’s important to know that well-stored, fresh oils can be detrimental when used improperly during cooking.
Every fat and oil has a value at which it burns called the smoke point.
An oil’s smoke point will change as it ages but also with repeated use.
At smoke point an oil’s fumes become toxic.
Fumes are not the only concern however.
The latest research speculates that cancer causing free radicals exist in oils that have reached their smoke point and/or been reheated. 2 (Note: The footnote is specific to coconut oil, but the theory applies to all fats and oils.)
Oils that have reached their smoke point may not change in color, smell, or taste. The only way to be confident in the safety of an oil is to watch for slight smoking as your food cooks.
Generally speaking, virgin or extra virgin grade oils have been extracted without the use of heat.
Doing so maintains the delicate integrity of a plant, nut, or seed’s phyto-nutrients. 1
Coconut oil is made by pressing the oil out of the fresh or dried meat of the coconut. Look for virgin, hexane-free, and cold-pressed labeling for the most benefits.
Top 5 Tips When Cooking With Oil
- Buy the freshest oils available and store them properly (each varies).
- Do not heat or eat food cooked in oil that has reached its smoke point.
- Turn hood ventilation fans on when frying foods.
- Do not use any oil that smells off or is past its expiry date.
- Know the age and expiry date of your oil and track how often it is reused between deep frying sessions.
Cut out the chart below; affix to an inside cupboard or drawer in your kitchen.
1 Natural chemicals from plant foods that may help your body work efficiently and prevent disease.
2 “Genotoxic and carcinogenic risks associated with the dietary consumption of repeatedly heated coconut oil” (November 2010) http://www.ncbi.nlm.nih.gov/pubmed/20687968