While it might seem perfectly fine to reuse cooking oil, to those who have been doing it their whole lives but many people cannot imagine doing so. Growing up my grandmother would always reuse cooking oil a few times but after reading this study, it is something I will never do myself.
A team of researchers from the University of Illinois at Urbana-Champaign recently carried out a study in which they looked at the effects of thermally abusing frying oil. This meaning they basically tested it to see if there were any health risks associated with repeatedly using the same cooking oil. This kind of thing is a lot more common than you might think and even many restaurants do it.
For this study, these researchers injected breast cancer cells into mice and then placed them in different groups. Some of the mice were placed on a diet with oil that hadn’t been reused and the others were placed on a diet with oil that had been ‘thermally abused.’ Quickly the researchers noted serious differences between the groups. According to their findings, the mice who were given the reused oil ended up metastasizing at a rate much faster than those who were given the fresh oil.
Deep-frying is a popular form of food preparation used globally and throughout in the United States. Each time dietary oils are heated to deep-frying temperatures, they undergo chemical alterations that result in a new matrix of lipid structures. These lipid products include triglyceride dimers, polymers, oxidized triglycerides, and cyclic monomers, which raises nutritional concerns about associations between these lipid products and heightened health risks. Reports of associations between thermally abused frying oil and deleterious health outcomes currently exist, yet there is little information concerning the effects of thermally abused frying oil consumption and the progression of breast cancer. This study used a late-stage breast cancer murine model and in vivo bioluminescent imaging to monitor the progression of metastasis of 4T1 tumor cells in animals consuming fresh soybean oil (SBO) and a thermally abused frying oil (TAFO). Bioluminescent and histologic examinations demonstrated that TAFO consumption resulted in a marked increase of metastatic lung tumor formation compared to SBO consumption. Further, in animals consuming the TAFO treatment diet, metastatic tumors in the lung displayed a 1.4-fold increase in the Ki-67 marker of cellular proliferation and RNA-sequencing analysis of the hepatic tissue revealed a dietary-induced modulation of gene expression in the liver.
Because reheating oil changes the way it is composed, it after a while begins to release a toxin known as acrolein which is quite dangerous even though not many people are aware of its presence. Sure, more research will need to be done on the topic but the carcinogenic effects of the acrolein are something we should not continue to ignore. If you look at the CDC’s website you will notice that it is listed as affecting things like our heart, blood vessels, eyes, and respiratory systems. Currently, it is gone over as a potential carcinogenic but as more and more information is being brought to light it’s very real carcinogenic effects are becoming quite clear.
While it might be a bit inconvenient for some, using new cooking oil each time you’re frying something might help save your life in the long-run. It is always better to be safe than sorry. Do you reuse oil and how do you feel about these findings?