Define Mechanisms for Provide protection against colon cancer?

Several plausable mechanisms have been formulated by which fibre may provide protection against colon cancer. These include:

1. Fibre that increases stool bulk results in the dilution of carcinogens. Fibre also decreases transit time thereby reducing the interactions of carcinogens with colonic mucosal cells.

2. Fibre binds potential carcinogens.

3. High bile acid concentrations are associated with increased risk of colon cancer. Fibres adsorb bile acids, thereby reducing the risk.

4. Fibre by providing fermentable substrate to colonic microflora alters species and number of microorganisms which may inhibit proliferation of tumor cells or conversion of procarcinogen to carcinogens.

5. Fermentation to SCFAs, reduces the pH, which in turn reduces synthesis of secondary bile acids. These bile acids have been shown to promote tumors.

6. Butyrate has been shown to have an effect on chromatin structure and thus could slow the proliferation and differentiation of cancer cells. Butyrate induces apoptosis (disintegration of cells).

7. Lignin may act as a free radical scavenger, thus reducing the risk of cancer.