Colon cancer, protection against

BARRETT J E, KLOPFENSTEIN c F, LEIPOLD H w (1998) Protective effects of cruciferous seed meals and hulls against colon cancer in mice. Cancer Lett. 127 83-8. 

HAGUE A, DIAZ G D, HICKS D J, KRAJEWSKI s, REED c, PARASKEVA c (1997) Blc-2 and bak may play a pivotal role in sodium butyrate-induced apoptosis in colonic epithelial cells however over expression of blc-2 does not protect against bak-mediated apoptosis. Int. J. Cancer 72 898-905. 

Bonnesen C, Eggleston I M and Hayes J D (2001), Dietary indoles and isothiocyanates that are generated from cruciferous vegetables can both stimulate apoptosis and confer protection against DNA damage in human colon cell lines , Cancer Rese, 61, 6120-6130. 

In conclusion, phytic acid forms soluble complexes with Ca2+ at intestinal pH under a variety of conditions and fails to inhibit Ca2 bioavailability to mice in our experimental system. Despite the hazard in direct extrapolation of results obtained with animals kept on a well-defined dietary regimen to humans consuming a complex diet, many elements of which affect Ca2+ bioavailability, our data demonstrate the need for a reevaluation of the putative antinutritional properties of dietary phytate. Our further contention that adequate levels of dietary phytate may actually be beneficial due to its food preserving properties and its protection against colonic cancer will warrant a prospective epidemiological human study designed to assess the longterm effects of dietary phytate on mineral bioavailability and inflammatory bowel diseases. 

As well as providing fuel, butyrate (which contains four carbon atoms) can reduce the proliferation of colonocytes, which may reduce the risk of tumour development. This is one suggestion to explain how high-fibre diets protect against colon cancer (Chapter 21). 

Several lifestyle factors predispose to cancer development, including smoking tobacco and exposure to sunlight (especially for children and the fair-skinned). It should be noted that low levels of continuous sun exposure may protect against breast and colon cancer, perhaps as a result of raising vitamin D levels which has already been discussed described. 

Rashmi R, Kumar S, Karunagaran D. 2004a. Ectopic expression of Bcl-XL or Ku70 protects human colon cancer cells (SW480) against curcumin-induced apoptosis while their down-regulation potentiates it. Carcinogenesis 25 1867-1877. 

Studies using animals suggest that regular consumption of flaxseed can protect against certain types of tumors and reduce the risk of colon cancer. Flaxseed, also called linseed, has been shown in some studies to improve kidney function, lower LDL cholesterol levels, and increase bowel movements. A compound derived from flax is being investigated as a possible treatment for lupus. 

Dietary fiber has been suggested to play a protective role against chemically-induced toxicity (1) and against colon cancer (2). However, the mechanism(s) by which dietary fiber modulates chemical toxicity or colon cancer has not been well studied. The fiber fraction of the diet is resistant to mammalian digestive enzymes and consequently dietary fiber is not absorbed from the small intestine (3). However, certain types of dietary fiber specifically fermentable fibers, including the pectic substances and hemicelluloses, are readily digested by the intestinal microflora (4,5). Pectic... 

However, despite the firm experimental basis and encouraging clinical studies, prophylaxis with NSAIDs to prevent colon cancer in patients who have polyps or in the population in general is notjustified because of the GI toxicity of such therapy. With the introduction of Cox-2 inhibitors, it now is feasible to test the hypothesis that inhibition of Cox-2 over prolonged periods of time would be protective against the development of colon polyps. Since it is well accepted that colon polyps are precancerous lesions, the prevention of polyps should translate into a reduction in the incidence of colon cancer. 

J. W. Finley, C. D. Davis, Y. Feng, Selenium from high-selenium broccoli is protective against colon cancer, J. Nutr., 130 (2000), 2384D2389. 

Bile acids that escape enterohepatic circulation and pass to the colon can be cytotoxic to colonocytes. Damaged cells undergo apoptosis and are shed into the lumen. To maintain cell homeostasis, new cells must be produced. This replacement can result in an increase in cell proliferation rate that can increase the risk of mutations in tumor-related genes and lead to carcinoma development. Moschetta et al. (2000) showed that sphingomyelin protected against bile acid-induced cytotoxicity in human CaCo-2 colon cancer cells, a common model for studying intestinal cell function. 

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