The study will recruit patients with newly diagnosed colorectal cancer and that has not yet undergone any chemotherapy treatment. Individuals that meet the inclusion criteria are randomized by means of a computer program on two study groups: 1) supplemented Experimental: receive 2g/day supplementation encapsulated fish oil for 9 weeks. 2) No intervention - control: not receive supplementation of fish oil or placebo. Will be assessed the effects of supplementation on the standard profile of cytokine production, nutritional status, and proportion of incorporation of these fatty acids in blood cells (mononuclear and red blood cells).