Dr. Harvey Murff of the Vanderbilt-Ingram Cancer Center said the omega-3 fats in fish -- tuna, salmon and sardines -- might reduce inflammation in the body and help protect against the development of colon polyps that might develop into cancer.
More than 5,300 participants were enrolled in the Tennessee Colorectal Polyp Study and received colonoscopies at Vanderbilt or the Veterans' Affairs Tennessee Valley Health System in Nashville.
Study participants completed food frequency questionnaires to determine how often they ate fish and investigators obtained urine samples from some of the patients to measure biomarkers for a hormone related to inflammation.
The study, published in the American Journal of Clinical Nutrition, found women who ate the equivalent of three servings of fish per week had about a 33 percent reduction in the risk for colon polyps and they also had a lower level of the hormone prostaglandin E2, which is linked to inflammation. However, men who ate more fish did not have a reduced risk of developing colon polyps.
"The difference between men and women may be linked to their background diet," Murff, the study's first author, said in a statement. "Even though men are eating more omega-3 fatty acids they may also be eating more omega-6 fatty acids and that may be blunting the effect."