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Resistant starch, background and emerging issues |
A. STEPHEN, Nutritional Sciences, CANTOX Health Sciences Int'l., 2233 Argentina Rd., Ste. 308, Mississauga, ON L5N 2X7, Canada The term “Resistant Starch” (RS) was coined in the early 1980’s by Hans Englyst, who found that some of the starch in food samples resisted degradation by  amylase and analyzed as Dietary Fibre. At a similar time, human feeding studies suggested that some of the starch in the diet was resistant to  amylase in vivo, and reached the large intestine. Since it did not reach the feces, it was assumed to be rapidly fermented by the colonic microflora. The finding that, on fermentation, starch produces the short chain fatty acid (SCFA), butyrate, in higher proportions that other substrates led to the hypothesis that RS was protective against colon cancer. Because butyrate had been shown to inhibit cell growth and promote differentiation in a number of cell lines in vitro. Although the evidence for a protective role for butyrate was persuasive, a number of animal feeding studies have shown increased intestinal cell turnover when RS is fed, seemingly contradicting the in vitro results. This paradox has been much discussed in recent years; some suggest what while SCFA stimulate cell turnover, this is in comparison to the low turnover rate of a low residue diet, and that there is little evidence that it results in the hyperproliferation of disease states. The general attitude towards RS remains one of it being a healthy ingredient. New research on RS had demonstrated benefits for disease states other than cancer. Moreover, combinations of RS with non-fermentable fibre sources extend the benefits of butyrate production to more distal regions of the colon. The food industry is responding to the beneficial properties of RS. Resistant starch is being incorporated into a number of food products from a variety of sources. An easy ingredient to incorporate, RS has many potential uses, with resulting benefits for the public.
Session 7, Resistant starch: A food ingredient with significant physiological and health benefits
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