Fish oil - long encouraged by doctors as a supplement to support heart and joint health, among other benefits - induced severe colitis and colon cancer in mice, a new research led by Michigan State University has shown.
Jenifer Fenton, a food science and human nutrition researcher at MSU, led the research that supports establishing a dose limit for docosahexaenoic acid (DHA), one of the omega-3 fatty acids present in fish oil, particularly in people suffering from chronic conditions such as inflammatory bowel diseases.
"We found that mice developed deadly, late-stage colon cancer when given high doses of fish oil," she said. "More importantly, with the increased inflammation, it only took four weeks for the tumors to develop."
Specifically, the research team found an increase in the severity of the cancer and an aggressive progression of the cancer in not only the mice receiving the highest doses of DHA but those receiving lower doses as well. The mice used in the study were prone to inflammatory-like bowel disease; inflammation is an important risk factor for many types of cancers, including colon cancer.
"Our findings support a growing body of literature implicating harmful effects of high doses of fish oil consumption in relation to certain diseases," Fenton said.
The research has been published in the journal Cancer Research.