Fish oil and cancer prevention

Increased dietary intake of fish oil, with its "healthy" omega-3 fatty acids, has been proposed to reduce risk of colorectal cancer. How it works is unclear, but it is thought to modify lipid signaling molecules associated with inflammation and carcinogenesis.

Harvey Murff, MD, MPH, and colleagues, conducted a randomized, double-blind, controlled trial of fish oil compared with olive oil supplementation in participants with a history of colorectal adenomas.

They evaluated levels of urinary and rectal lipid signaling molecules. Fish oil supplementation reduced urinary PGE-M. It did not reduce rectal PGE2 overall, but it did reduce PGE2 in participants not using aspirin or other NSAIDs. A genetic variation that affects cellular fatty acid levels did not modify the effects of fish oil on PGE2.

The findings, reported in the European Journal of Cancer Prevention, demonstrate a modest but beneficial effect of fish oil supplementation on molecules associated with colorectal cancer development and support further studies of fish oil fatty acids as cancer prevention agents.