Advances in dietary fibre characterisation. 2. Consumption, chemistry, physiology and measurement of resistant starch; implications for health and food labelling

Abstract

Resistant starch (RS) is defined as 'the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals'. This basic definition includes different types of starches that (1) are physically inaccessible, usually due to an encapsulation in intact cell walls, or (2) are naturally highly resistant to mammalian α-amylase, or (3) have been modified by hydrothermic treatments then retrograded. Interest in RS has increased significantly during the last two decades, mostly due to its capacity to produce a large amount of butyrate all along the colon. Butyrate has been observed to have a range of effects on cell metabolism, differentiation and cell growth as well as inhibition of a variety of factors that underlie the initiation, progression and growth of colon tumours. The physiological definition of RS, which seems to be nearly consensual, raises a difficulty in proper analytical quantification of RS. A number of methods have, however, been proposed and provide similar values for the RS content in most of the starch types and starchy foods. It seems, however, that some starches, proven to be partly resistant according to in vivo investigations on ileostomy subjects, could not be quantified by most of these methods. This may be due to a widespread use of glucoamylase during the first steps of these methods. Accordingly, there is an international debate on health aspects of RS and on how to quantify the RS content of food products. The present review describes aspects of classification of RS, past and current consumption, physiological effects and analytical aspects, and concludes with impacts on food and product labelling. Dietary fibre: Resistant starch: Food analysis: Food labellingAbbreviations: ACF, aberrant crypt foci; AOAC, Association of Official Analytical Chemists; BA, butyric acid; EURESTA, European Flair-Concerted Action Research Programme; RS, resistant starch; RS1, physically inaccessible starch; RS2, resistant starch granules; RS3, retrograded starch; RS4, chemically modified starch; SCFA, short-chain fatty acids. * Corresponding author: Dr Martine Champ, fax +33 2 40 67 50 12, email champ@nantes.inra.fr IntroductionResistant starch (RS) is present in a wide variety of carbohydrate-based foods and may constitute up to 15 % of the DM of a food product. Several studies indicate that its presence in food might be beneficial for health (Asp et al. 1996). RS is by definition not absorbed in the small intestine (Asp, 1992), thus it does not contribute to postprandial hyperglycaemia . Its effect on lipid metabolism has recently been investigated. When added to meals, RS may be beneficial for patients with subnormal or abnormal levels of lipaemia . Moreover, some animal studies indicate a serum cholesterol-lowering effect but no evidence of similar effects in human subjects has been demonstrated (Heijnen et al. 1996). RS is largely fermented, producing short-chain fatty acids (SCFA) and bacterial cells. It may be important for colonic epithelial cell health through effec...

Gastrointestinal responses following acute and medium term intake of retrograded resistant maltodextrins, classified as type 3 resistant starch

“…Currently calculated intakes range from about 4 to 8.5 g/day in European countries (Tomlin and Read, 1990;Brighenti et al, 1998;Wisker, 2000), which is comparable to quantities consumed in Australia (Baghurst et al, 1996). However, it has been suggested that in some individuals, consuming high amounts of starch containing foods, daily intake of RS may be substantially higher (Champ et al, 2003). In some clinical studies amounts up to 45 g/day have been ingested (van Munster et al, 1994;Phillips et al, 1995;Heijnen et al, 1997), but no data were mentioned on digestive tolerance.…”

“…Studies in ileostomy patients (Langkilde et al, 2002) have shown that the non-digestible fraction of the product amounts to 59%, the remainder being digestible carbohydrate'. The indigestible RRM fraction is quantified appropriately by the 2002.02 AOAC method for measuring RS (Champ et al, 2003). In both parts of the study a powdered chocolate drink and a dried vegetable soup, containing either digestible starch (DS) or RRM containing product, were provided in bags, in addition to a menu of cereal bars and breakfast muesli.…”

“…The increasing knowledge of starch digestion in humans has allowed a new classification of types of RS that has now been commonly accepted (Englyst et al, 1992Champ et al, 2003). Three classes of RS are usually described in literature but recently a fourth class also has been described: RS 1 : physically inaccessible starch.…”

“…Type 4 RS may differ in fermentation behaviour depending on its modified molecular structure. Recently, a number of review publications have highlighted the physiological properties as well as the effects of RSs on intestinal digestion, physiology, flora and fermentation (Cummings and Englyst, 1991;Cummings et al, 1996;Topping and Bird, 1999;Bird et al, 2000;Topping and Clifton, 2001;Champ 2003).…”

High-resolution time-of-flight mass spectrometry fingerprinting of metabolites from cecum and distal colon contents of rats fed resistant starch

“…Amylose can also form single helical complexes with free fatty acids and iodine. These modified amylose structures along with food materials that contain up to 85 % amylose are examples of resistant starch (RS) [3], which effectively resist digestion in the stomach and small intestine, and thus are processed farther along the gut [4].…”