A new study has discovered a connection between cooking oil that has been repeatedly used with breast cancer.

The research, which included lab mice that consumed reused cooking oil, found that frequent reused oil intake may trigger the growth and expansion of cancer-causing cells. No such effects were seen in lab mice that were given fresh cooking oil.

The study came out of the University of Illinois, where scientists assessed the impacts of "thermally abused" cooking oil on mice who had been infused with breast cancer cells. These cells are known to forcefully grow in different parts of the body such as swollen glands and lungs.

For the study, frying oil that was continuously heated to soaring temperatures was utilized. This is the same kind of cooking oil that is used by fast food chains.

At the beginning of the study, a low-fat diet was fed to the lab mice for a single week, after which one group was given fresh soybean oil, while another group was fed "thermally abused" oil.

This experiment continued for four months on the two groups of mice. By the 20th day of the trial, the mice given used cooking oil had four times the number of cancer cells as the mice given fresh soybean oil.

In addition, the study also found that the reused cooking oil group had more lung disease metastases than the fresh oil gathering of mice.

Likewise, "increasingly forceful & intrusive cancer tumors" were found in the group of mice that had been fed thermally abused oil. This highlighted the impact that devouring used cooking oil has on cancer survivors.

This study was recently published in the journal Cancer Prevention Research.

"I simply accepted these knobs in the lungs were little clones – however, they weren't," Professor William G. Helferich told Medical News Today. "They'd experienced the change to turn out to be increasingly forceful. The metastases in the fresh oil group were there, yet they weren't as intrusive or forceful, and the expansion wasn't as broad." 

In the study, reused cooking oil that has been heated to high temperatures more than once experiences a breakdown of triglycerides, prompting the oxidation of free unsaturated fats and discharge of a dangerous cancer-causing agent called acrolein. According to past studies, acrolein in reused oil increases the risk of health issues, such as atherosclerosis and other coronary illnesses.

Though people don't usually utilize reused cooking oil, some individuals generally still consume it when they eat fried fast food. It is a common practice among fast food chains and restaurants as utilizing reused oil is much cheaper than using new and fresh oil each day.