Women who eat at least 3 servings of fish per week are less likely to develop some types of colon polyps, according to researchers from the Vanderbilt-Ingram Cancer Center in Nashville, Tennessee, in a study published in the American Journal of Clinical Nutrition.1

Lead author Harvey Murff, MD, MPH, and colleagues say that omega-3 fats in fish may reduce inflammation and protect against the development of colon polyps, which can develop into cancer.

Although previous animal studies have demonstrated this link, human studies have been inconclusive. More than 5300 individuals were enrolled in the Tennessee Colorectal Polyp Study and underwent colonoscopies. They completed questionnaires to say how often they ate fish, and some participants provided urine samples to be measured for a hormone related to inflammation.

Women who ate 3 servings of fish per week had an approximately 33% reduction in the risk of colon polyps. At the same time, they also had a lower level of the hormone prostaglandin E2, which is linked to inflammation and also is known to be associated with adenomas of polyps in colorectal cancers, Dr. Murff notes. Fish oil appears to have effects similar to aspirin in reducing inflammation and thus possibly preventing the formation of polyps, he adds.

Men who ate more fish in the study, however, did not have a reduction in the development of colon polyps. Dr. Murff speculated that men may be eating more omega-6 fatty acids, which are found in meats, grains, and in corn, safflower, and sunflower oils, and may counteract the protective effect of omega-3 fatty acids. At the same time, not all fish are high in omega-3 fatty acids. Tuna, salmon, and sardines are, whereas tilapia and catfish are not.

Researchers are conducting a clinical trial to determine the effect of fish oil supplementation and prostaglandin E2 production to validate their results.



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