You should increase your intake of omega-3 oils, especially the docosahexaenoic acid (DHA) component, which reduces cancer by reducing inflammation, inhibiting angiogenesis, regulating cell signaling, and enhancing anticancer immunity. DHA has also been shown to selectively kill cancer cells.
N-butyrate is a major fuel for the cells lining the intestines and colon, and higher levels have been shown to kill colon cancer cells as well as other cancer cells. Several studies have found that DHA combined with N-butyrate dramatically kills human colon cancer cells.
N-butyrate has also been shown to reduce the abnormal sites of colon cancer generation and as a result inhibits the formation of the sessile polyps associated with colon cancer development. DHA has also been shown to powerfully inhibit the formation of polyps in the colon.
Olive oil alters the microbes in the colon in a way that inhibits colon cancer. It also significantly reduces inflammation within the colon. On the other hand, coconut oil and sunflower oil worsened colon inflammation in experiments. Other studies found extra-virgin coconut oil to be anti-inflammatory.
While I use coconut oil to cook with, I always add powdered turmeric to the oil, which makes it powerfully anti-inflammatory and anti-carcinogenic. Colon cancer is far less common in India than in the United States, mainly because they use turmeric and cumin in much of their food. If you use extra-virgin olive oil to cook, add turmeric as well and keep on a lower temperature. Turmeric is heat resistant but some of the olive oil components will oxidize with high heat.
While curcumin is a powerful inhibitor of colon cancer, turmeric may be even more beneficial.
For those in a high risk category, I suggest using turmeric on foods and in cooking oils, and taking nano-curcumin. In this way the turmeric comes into contact with the lining and contents of the colon and the nano-curcumin saturates the wall of the colon and draining lymph nodes.