Even healthy-seeming oils like avocado oil can break down into harmful stuff when heated because they have too much of a fragile kind of fat.
Scientific Claim
Oils with polyunsaturated fatty acid content exceeding 10% are susceptible to thermal oxidation during cooking, generating harmful aldehydes and polar compounds even below smoke point.
Original Statement
“Avocado oil is about 70% monounsaturated fat. Now, this is a moderately stable fat, but it still contains a relatively significant amount of polyunsaturated fat, roughly 13 to 15%. This is the type of fat that's most vulnerable to oxidization and heat damage.”
Context Details
Domain
nutrition
Population
unspecified
Subject
oils with >10% polyunsaturated fatty acids
Action
undergo thermal oxidation
Target
formation of aldehydes and polar compounds
Intervention Details
Evidence from Studies
Supporting (3)
Impact of Heating Temperature and Fatty Acid Type on the Formation of Lipid Oxidation Products During Thermal Processing
The study found that oils with lots of polyunsaturated fats (like soybean oil) create more harmful chemicals when heated, even before they start smoking, while oils with fewer of these fats don’t produce as much.
Comparison of Furans Formation and Volatile Aldehydes Profiles of Four Different Vegetable Oils During Thermal Oxidation.
Scientists heated different cooking oils and found that oils with lots of certain healthy fats (polyunsaturated fats) produced harmful chemicals when cooked—even without smoking. This matches the claim that these oils can become dangerous when heated.
The study found that fats with certain unsaturated fats (like those in pork) break down into harmful chemicals when heated, but adding spices can slow this down—proving that these fats can indeed go bad during cooking even without smoking.
Contradicting (1)
Effect of cooking temperature and time on the quality and safety of hemp seed oil.
Even when heated pretty hot, hemp oil didn’t turn harmful like the claim says it should—so the claim might be too broad or wrong.