So why is smoke point important? For starters, low-level exposure to acrolein, the byproduct found in smoke from burning oil, can irritate the eyes, nose, and throat. And while that is extremely unpleasant, the biggest problem is repeated exposure.
“Unfortunately, it is more harmful to heat an oil past its smoke point than the irritating smoke it produces,” says Lindsay Wengler, MS, RD, CDN, CNSC, a registered dietitian in Olive Branch Nutrition in New York “An oil heated beyond its smoke point can not only catch fire, but the molecular breakdown of the oil can create pro-inflammatory free radicals and a carcinogenic compound, acrolein, which can be detrimental to health.”
Ferira further explains the mechanisms of this troublesome aldehyde compound: “Acrolein is highly reactive and over time can interfere with DNA by cross-linking it. It also has the potential to get in the way of essential detoxifying enzyme systems in the liver as cytochrome P450 and throughout the body by inhibiting glutathione pathways.”
Regular exposure to acrolein has also been associated with heart disease and several others diseases. But the keywords here are “regular exposure”. The occasional burnt oil isn’t a big deal, but you don’t want to make a habit of it.
And never reuse hot oil. Overheating oil can create a number of carcinogenic compounds, including polycyclic aromatic hydrocarbons (PAHs), which have been related to various types of cancer.
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