A study published in Cancer Prevention Research examined the impact of frying oil consumption on inflammatory bowel disease (IBD) and colon cancer, using animal models.
For the experiments, the researchers used a real-world sample of canola oil, in which falafel had been cooked at 325℉ in a standard commercial fryer at an eatery in Amherst, Mass. They performed the analysis of the oil, which undergoes an array of chemical reactions during the frying process, characterizing the fatty acid profiles, the level of free fatty acids, and the status of oxidation. A combination of the frying oil and fresh oil was added to the powder diet of one group of mice. The control group was fed the powder diet with only fresh oil mixed in.
The researchers looked at the effects of the diets on colonic inflammation, colon tumor growth, and gut leakage, finding that the frying oil diet worsened all the conditions. “The tumors doubled in size from the control group to the study group,” said study author Guodong Zhang, associate professor in food science at the University of Massachusetts Amherst.
To test their hypothesis that the oxidation of polyunsaturated fatty acids, which occurs when the oil is heated, is instrumental in the inflammatory effects, the researchers isolated polar compounds from the frying oil and fed them to the mice. The results were “very similar” to those from the experiment in which the mice were fed frying oil, suggesting that the polar compounds mediated the inflammatory effects.
While more research is needed, the researchers hope a better understanding of the health impacts of frying oil will lead to dietary guidelines and public health policies.