Physical inactivity and high Body Mass Index (BMI) have been shown to increase risk of colon cancer in some studies. Almost 42% of colon cancer patients are obese. Presently, 1 in 3, or 58 million American adults age 20 through 74 are overweight or obese (National Institute of Diabetes and Digestive and Kidney Diseases, 1997). According to some studies, overweight and obesity among men specially in middle age can increase the risk of developing colon cancer (Lee & Paffenbarger, 1992).
Some studies have shown that inactivity and a high fat diet which leads to overweight or obesity for some individuals may increase the risk of colorectal cancer (Lee & Paffenbarger, 1992; Martinez et al. , 1997). Summary The review of the literature has shown that colon cancer is also the result of environmental factors. One environmental factor that is believed to increase the risk of colon cancer is high consumption of fat and meat. Again, results are not consistent. Researchers also have claimed that extra fat can trigger secretion of secondary bile acid.
Another hypothesis suggested that unsaturated fat can be easily oxidized by hydroxyl radicals which are produced by bacteria in the intestine resulting in the production of lipid oxyl radicals. These substances can damage the DNA of epithelial cells in the large intestine. To suppress this path, consuming fresh fruits and vegetables which are high in antioxidants and fiber are recommended. Some studies have also shown existence of a negative association between serum cholesterol and colon cancer; however, the results are inconsistent.
Two mechanisms hypothesized for low serum cholesterol include secretion of cholesterol into the gut and unbalancing of cholesterol in the bilayer of epithelial cells. These suggested hypothesizes are controversial. In spite of numerous epidemiology, bimolecular, and genetic studies, and advances in colon cancer, this fatal disease continues to kill thousands of people throughout the world. Based on the review of literature in this study, further research needs to be carried out to fully understand how to root out this dreaded disease.
The present study examined over 50 research articles with the objective of obtaining all the available information and results pertaining to the subject under investigation, i. e. the linkage between colon cancer and cholesterol and obesity. Only one study (Kreger, Anderson, Schatzkin, & Spalnsky, 1992) directly addressed the linkage mentioned above. The present study is designed to examine the possible linkage that exists between colon cancer and cholesterol and obesity.
References: Jemal, A. , Siegel, R. , Ward, E. et al. 2007. Cancer statistics. CA Cancer J. Clin. , 57:43–66.