Stop! Put down those fries! Although we know that fried foods aren’t good for our health (though they sure do taste good!), new research from UMass Amherst and published in Cancer Prevention Research investigates the effects of frying oil consumption specifically on inflammatory bowel disease (IBD) and colon cancer. The study concludes that frying oil consumption results in exaggerated colonic inflammation, enhanced tumor growth and worsened gut leakage, which ultimately increases the dissemination of bacteria or toxic bacterial products into the bloodstream.
Lead author of the study Jianan Zhang commented, "People with colonic inflammation or colon cancer should be aware of this research.” But the authors of the study aren’t trying to scare you, necessarily. "It's not our message that frying oil can cause cancer," explains associate professor Guodong Zhang, one of the researchers who worked on the study. Rather, they hope to spread awareness: "If somebody has IBD or colon cancer and they eat this kind of food, there is a chance it will make the diseases more aggressive,” added Zhang.
The study was conducted using samples of canola oil, a commonly-used oil for frying in the United States. Researcher Eric Decker then analyzed the lipid chemistry of the oil during the frying process to determine the level of free fatty acids and the status of oxidation. Based on this analysis, the researchers gave mice one of two diets: the control diet of power with only fresh oil or the experimental diet of power mixed with frying and fresh oil.
The scientists found that the frying oil diet worsened colonic inflammation, colon tumor growth, and gut leakage significantly. "The tumors doubled in size from the control group to the study group," Guodong Zhang says.
Interestingly, the researchers were also able to figure out that the difference in impact between fresh oil consumption and frying oil consumption comes during the process of heating. “The oxidation of polyunsaturated fatty acids, which occurs when the oil is heated, is instrumental in the inflammatory effects,” explains Science Daily.
Though the scope of the study’s findings is still limited, as it was conducted using animal models and not human models, the researchers hope that it will help widen our understanding of the health impacts of frying oil. "For individuals with or prone to inflammatory bowel disease," Guodong Zhang concludes, "it's probably a good idea to eat less fried food."