A A C C   2 0 0 0   A n n u a l   M e e t i n g

Since the early 1980's it has been recognized that starch can contribute in many ways to an individual's health and well being. The consumption of low levels of dietary starch seems to be associated with physiological conditions, such as colorectal cancer (1). One important reason for the health benefits that appear to be derived from starch consumption stems from the ability of a portion of the dietary starch to resist enzymatic digestion in the small intestine (2) and make a positive impact on the health of the large bowel. The term "resistant starch" is used to describe this type of starch. There are at least four sub - types of resistant starch (3) and the assessment of the physiological effects of these various types of resistant starch is underway. The physiological effects of resistant starch occur in the small intestine, through reducing the post-prandial glycaemic and insulinemic responses, which is advantageous for people with impaired insulin sensitivity (4,5), and in the large bowel. In the large bowel, resistant starch is predominantly fermented by the resident microflora to provide elevated levels of short chain fatty acids (5,6,7), in particular butyrate, and other products, which are believed to contribute to bowel health. There is also a marked reduction in the amount of cytotoxic compounds, such as secondary bile acids (6,7), which are normally produced in the large bowel. It has also been demonstrated that the type of resistant starch introduced into the large bowel (8) can significantly effect the rate of fermentation by the colonic microflora. Research has been undertaken to prepare resistant starches, naturally, or through chemical, physical or enzymatic derivatisation, to selectively encourage probiotic bacteria (9), both indigenous (10) and introduced strains (11), in a variety of ways, including the rate of bacterial growth and the type and quantity of fermentation products they produce. The availability of resistant starch ingredients, supported by clinical assessment and innovative food engineering, has combined to provide consumers with foods with greater nutritional quality while meeting their demands for organoleptic acceptability. Nutritional research is continuing to identify new uses for resistant starch ingredients, alone or in combination with other dietary components (12,13), to address public health concerns. References (1) Cassidy, A., et al Br. J. Cancer. 69 : 119-125 (1994) (2) EURESTA. EURESTA Newsletter. 11: 1 (1991) (3) Brown, I., et al Food Australia. 47 (6) : 272-275 (1995) (4) Byrnes, S., et al J. Nutr. 125: 1430-1437 (1995) (5) Noakes, M., et al Am. J. Clin. Nutr. 64: 944-951 (1996) (6) Phillips, J., et al Am. J. Clin. Nutr. 62: 121-130 (1995) (7) Topping, D., et al J. Nutr. 127: 615-622 (1997) (8) Bird, A. R., et al Private Communication. 1999. (9) Brown, I. L., et al Food Australia 50 (12) : 603-610 (1998) (10) Wang, X., et al J. Appl. Environ. Micro. 65 (11) : 4848-4854 (1999) (11) Brown, I. L., et al J. Nutr. 127: 1822-1827 (1997) (12) Morita, T., Private Communication (1999) (13) Higgins, J., et al Private Communication (1999)