Here’s another reason you should think twice before eating fried foods.

In a paper published last week in Cancer Prevention Research, University of Massachusetts Amherst researchers found that eating food fried in one common vegetable oil can worsen existing inflammatory bowel disease or colon cancer.

While researchers have long studied the effect of frying oil consumption on healthy people, the study is the first to look at the impact on those who have the two intestinal diseases.

“For individuals who have or are prone to IBD or colon cancer, diets with frying oil can make the disease much more aggressive or dangerous,” said Guodong Zhang, a food science professor at UMass Amherst and one of the report’s authors. He noted that the study did not look at whether frying oil consumption causes cancer.


More than a million Americans have IBD, and colon cancer is the third most common cancer and the second-leading cause of cancer-related death in the US, according to Zhang.

Given the growing prevalence of IBD in recent decades, Zhang said it is important to identify factors, including diet, that increase the risk of developing the disease.

“IBD is a serious health problem, but it is also increasing very dramatically,” Zhang said. “This rapid development cannot be explained only by genetic factors.”

In their experiment, researchers induced mice to develop IBD or colon cancer.

A combination of canola oil that had been used for frying and fresh oil was then added to the powder diet of one group of mice. The control group was only fed fresh oil with their powder, according to the study.

In order to better mimic human consumption, researchers used a sample of canola oil from a local eatery. The oil had been used to fry falafel for one week. They fed the mice very small amounts of the oil, Zhang said.


The results showed that the frying oil diet increased colonic inflammation, gut leakage, and colon tumor growth.

“The tumors from mice treated with frying oil are double in size compared to the tumors of the mice treated with fresh oil,” Zhang said.

The researchers said that chemical reactions during the frying process led to the formation of harmful compounds.

The researchers also said they “expected that other types of frying oil, e.g. soybean oil, could induce similar adverse effects.”

Zhang said he hoped the research could help people make healthier decisions and aid the government in revising dietary recommendations.

Health experts suggest that people should limit their fried food intake.

Sarah Wu can be reached at sarah.wu@globe.com. Follow her on Twitter at @sarah_wu_.