Why some cooking oils make more yucky stuff when heated
Oxidative Stability and Genotoxic Activity of Vegetable Oils Subjected to Accelerated Oxidation and Cooking Conditions
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Coconut oil produced the highest total volatile compounds (35x increase) but was the most stable during storage and showed no mutagenicity.
People assume saturated fats are 'bad' and unsaturated are 'good'—but here, the most saturated oil produced the most volatiles under heat, yet was least prone to oxidation over time and caused zero DNA damage.
Practical Takeaways
Use coconut oil or avocado oil for high-heat frying; reserve grape seed, rapeseed, and sunflower oils for dressings or low-heat cooking.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Coconut oil produced the highest total volatile compounds (35x increase) but was the most stable during storage and showed no mutagenicity.
People assume saturated fats are 'bad' and unsaturated are 'good'—but here, the most saturated oil produced the most volatiles under heat, yet was least prone to oxidation over time and caused zero DNA damage.
Practical Takeaways
Use coconut oil or avocado oil for high-heat frying; reserve grape seed, rapeseed, and sunflower oils for dressings or low-heat cooking.
Publication
Journal
Foods
Year
2023
Authors
D. Ansorena, R. Ramírez, A. López de Cerain, A. Azqueta, I. Astiasarán
Related Content
Claims (6)
If you heat cooking oil at a pretty high temperature for an hour and a half, the types of fats in it don’t change enough to matter for your health.
When you heat coconut, rapeseed, and grape seed oils at a high temperature for a long time, they produce way more smelly chemicals—up to 35 times more in coconut oil—and most of those smells come from aldehydes, which are signs the oil is breaking down from the heat.
When scientists heated or stored coconut, rapeseed, and grape seed oils at high temperatures, they found no evidence that these oils turned into substances that could damage DNA — even when they mimicked how the body processes chemicals.
When you cook with certain plant oils like sunflower or soybean oil, even at normal cooking temps that aren’t hot enough to make them smoke, they can break down into harmful chemicals — and if you heat them for 30 minutes straight, those harmful chemicals become ten times more toxic.
When scientists use a common test to check if oils like rapeseed or grape seed oil have gone bad from heating, the test might miss how bad they really are because it can't see some of the chemicals that form during heating — even though those chemicals are definitely there.