Foods fried are popular worldwide, but research about the health effects of this cooking technique has raised concerns among healthcare providers, including about its impact on inflammatory bowel disease (IBD) and colon cancer among others.
Scientists at the University of Massachusetts in the US set out to examine this impact in more detail, using animal models.
The study showed that feeding frying oil to mice exaggerated colonic inflammation, enhanced tumor growth and worsened gut leakage, spreading bacteria or toxic bacterial products into the bloodstream. “People with colonic inflammation or colon cancer should be aware of this research,” said the scientists.
The new research suggests that eating fried foods may exacerbate and advance conditions of the colon. If somebody has IBD or colon cancer and they eat this kind of food, there is a chance it will make the disease more aggressive, the researchers warned.
For their experiments, the researchers used a real-world sample of canola oil, in which falafel had been cooked at 163 C in a standard commercial fryer. A combination of that 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 then looked at the effects of the diets on colonic inflammation, colon tumor growth and gut leakage, and found that the frying oil diet worsened all the conditions. To test whether 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 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.