Global cancer data showed that colon and rectum cancers (also known as colorectal cancer/CRC) accounted for about 1 million new casesin 2002 (9.4% of the world total). In termsof incidence, colorectal cancers rank fourth in frequency inmen and third in women. Around 15% of CRC is inherited (direct and indirect), the others is acquired.  Up to 80% of CRC cases have been attributed to diet.  It suggests that CRC is preventable disease.
The above condition leads us to pursue basic research on the development of resistant starch type 3 (RS3) as one of the functional food ingredient with cancer prevention ability.  RS type 3 is retrograded starch, which is not digested by human starch degrading enzyme and, will thus undergo bacterial fermentation in the colon.  The main fermentation products are the short chain fatty acid (SCFA) acetate, propionate and butyrate. Butyrate has been implicated in providing protection against cancer; it is also preferred energy substrate of the colonocytes.  RS type 3 derived from different origin of sources and processing conditions have different structures and a wide range of physical and chemical properties. Thus, it can be assumed that molecular properties of RS may influence the SCFA production by colonic butyrate producing bacteria. The increasing of SCFA would inhibit the proliferation of cancer cell.