Why some oils smoke and get yucky when you cook with them
Impact of Heating Temperature and Fatty Acid Type on the Formation of Lipid Oxidation Products During Thermal Processing
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you heat oils, they break down and make chemicals that might be bad for you. Oils with lots of double bonds (like soybean oil) break down faster and make more of these chemicals than oils with fewer double bonds (like olive or lard oil).
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
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Max 72Case-Control Studies
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Evidence Score
A snapshot of a population at a single point in time. Can identify correlations and prevalence, but cannot determine the direction of cause and effect.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you heat oils, they break down and make chemicals that might be bad for you. Oils with lots of double bonds (like soybean oil) break down faster and make more of these chemicals than oils with fewer double bonds (like olive or lard oil).
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
Max 100Randomized Controlled Trials
Max 90Cohort Studies
Max 72Case-Control Studies
Max 58Cross-Sectional Studies
Max 44Case Reports & Case Series
Max 30Expert Opinion & Narrative Reviews
Max 56 / 44
Evidence Score
A snapshot of a population at a single point in time. Can identify correlations and prevalence, but cannot determine the direction of cause and effect.
Publication
Authors
Zhuang Y, Dong J, He X, Wang J, Li C, Dong L, Zhang Y, Zhou X, Wang H, Yi Y, Wang S
Related Content
Claims (10)
When you cook oils at high heat, especially above 180°C, they break down and make more harmful chemicals — the hotter it gets, the more chemicals form.
Oils with lots of unsaturated fats, like soybean oil, produce way more toxic chemicals when heated to frying temperatures than oils with more saturated fats.
Olive oil’s polyunsaturated fat content (11%) renders it more susceptible to thermal oxidation than animal fats with lower PUFA content (e.g., tallow, ghee <2%).
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.
The more linolenic acid (a type of omega-3) an oil has, the more MDA and 4-HHE it makes when heated — these chemicals only show up in oils with this specific fat.