Colon cancer risk depends on interaction between omega-3s and inflammation genes

Colon cancer risk? Because of the interaction between Omega 3 and inflammation genes

Omega 3s reduce the risk of colorectal cancer by interacting with genes that control inflammation. A group of researchers led by Nina Habermann of the National Center for Tumor Diseases in Heidelberg, Germany, demonstrated the existence of this interaction. The study was published in the journal Genes and ^Nutrition1. The research authors identified those who consume low amounts of Omega-3 rich foods as more likely to develop this cancer if genes that increase levels of proinflammatory molecules are present.

The role of omega-3s in inflammation

Polyunsaturated fatty acids are a group of nutrients to which both Omega-3 and Omega-6 belong. They are transformed by the body into prostaglandins and leukotrienes, molecules that control inflammatory phenomena. In general, the effect of substances produced from Omega-6 is totally opposite to that of molecules obtained from Omega-3: while the former stimulate inflammation, the latter reduce its levels. Several studies have shown thatOmega-3 intake reduces inflammation, helping to counteract several disorders associated with this phenomenon. These include colorectal cancer, a form of cancer also associated with inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. The incidence of this type of cancer is significantly lower in populations that eat high amounts of fish rich in^Omega-32. Not only that, the intake of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the 2 most important Omega-3s contained infish oil, decreases the formation and proliferation of precancerous polyps3^,4. Given the existence of these links between Omega-3s, inflammation, and colon cancer, Habermann and colleagues hypothesized that consuming high amounts of Omega-3-rich fish may reduce the risk of colorectal cancer in those who possess genes whose activity increases levels of pro-nonflammatory molecules.

Genes that promote inflammation

Researchers compared genes present in 1,574 individuals with colon cancer and 791 patients with rectal cancer with those present in individuals without this cancer. As a result, it was found that taking low levels of Omega-3 increases cancer risk if variants in the PTGS1, PTGS2 and ALOX15 genes that lead to the production of higher levels of prostaglandins and leukotrienes are present. In particular, cancer risk is higher for those who carry this PTGS1 variant and take low levels of DHA. Similarly, cancer is more frequent if those with the inflammation-enhancing form of ALOX15 take little EPA. Based on these findings, the researchers concluded that the combination of Omega-3 levels and gene variants in the body can determine the risk of developing colon cancer.  

Sources 1. Habermann N, Ulrich CM, Lundgreen A, Makar KW, Poole EM, Caan B, Kulmacz R, Whitton J, Galbraith R, Potter JD, Slattery ML, "PTGS1, PTGS2, ALOX5, ALOX12, ALOX15, and FLAP SNPs: interaction with fatty acids in colon cancer and rectal cancer," Genes Nutr. 2012 Jun 8. [Epub ahead of print] 2. Schloss I, Kidd MS, Tichelaar HY, Young GO, O'Keefe SJ, "Dietary factors associated with a low risk of colon cancer in colored west coast fishermen," S Afr Med J. 1997 Feb;87(2):152-8 3. Anti M, Marra G, Armelao F, Bartoli GM, Ficarelli R, Percesepe A, De Vitis I, Maria G, Sofo L, Rapaccini GL, et al, "Effect of omega-3 fatty acids on rectal mucosal cell proliferation in subjects at risk for colon cancer," Gastroenterology. 1992 Sep;103(3):883-91. 4. Huang YC, Jessup JM, Forse RA, Flickner S, Pleskow D, Anastopoulos HT, Ritter V, Blackburn GL, "n-3 fatty acids decrease colonic epithelial cell proliferation in high-risk bowel mucosa," Lipids. 1996 Mar;31 Suppl:S313-7