http://www.enfermeraspabellonyesterilizacion.cl/eventos/glycemic-index.pdf

International table of glycemic index and glycemic load values: 2002

Historically, nutrition principles and recommendations for diabetes and related complications have been based on scientific evidence and diabetes knowledge when available and, when evidence was not available, on clinical experience and expert consensus. Often it has been difficult to discern the level of evidence used to construct the nutrition principles and recommendations. Furthermore, in clinical practice, many nutrition recommendations that have no scientific supporting evidence have been and are still being given to individuals with diabetes. To address these problems and to incorporate the research done in the past 8 years, this 2002 technical review provides principles and recommendations classified according to the level of evidence available. It reviews the evidence from randomized, controlled trials; cohort and case-controlled studies; and observational studies, which can also provide valuable evidence (1,2), and takes into account the number of studies that have provided consistent outcomes of support. In this review, nutrition principles are graded into four categories based on the available evidence: those with strong supporting evidence, those with some supporting evidence, those with limited supporting evidence and those based on expert consensus.

Evidence-based nutrition recommendations attempt to translate research data and clinically applicable evidence into nutrition care. However, the best available evidence must still be moderated by individual circumstances and preferences. The goal of evidence-based recommendations is to improve the quality of clinical judgments and facilitate cost-effective care by increasing the awareness of clinicians and patients with diabetes of the evidence supporting nutrition services and the strength of that evidence, both in quality and quantity.

Before 1994, the American Diabetes Association’s (ADA’s) nutrition principles and recommendations attempted to define an “ideal” nutrition prescription that would apply to everyone with diabetes (3,4,5). Although individualization was a major principle of all recommendations, it was usually done within defined …

/pdf/evidence-based-nutrition-principles-and-recommendations-for-219364socu.pdf

Evidence-Based Nutrition Principles and Recommendations for the Treatment and Prevention of Diabetes and Related Complications

Summary Resistant starch (RS) refers to the portion of starch and starch products that resist digestion as they pass through the gastrointestinal tract. RS is an extremely broad and diverse range of materials and a number of different types exist (RS1–4). At present, these are mostly defined according to physical and chemical characteristics. RS may be categorised as a type of dietary fibre, as defined by the American Association of Cereal Chemists and the Food Nutrition Board of the Institute of Medicine of the National Academies. RS is measured in part by the methodology recommended by the Association of Official Analytical Chemists for measuring dietary fibre. Dietary intakes of RS in westernised countries are likely to be low. However, accurate comparative assessments of dietary intakes between countries, and subsequent epidemiological analysis, are absent due to the lack of consensus over of an agreed, repeatable and simple in vitro method for analysing the RS content of foods. At present, the recognised method is that of McCleary & Monaghan (2002). RS appears to confer considerable benefits to human colonic health, but has a smaller impact on lipid and glucose metabolism. Comparisons between studies are hampered by differences in study design, poor experimental design and differences in the source, type and dose of RS in the ingredients or diets used. It is likely that RS mediates some or all of its effects through the action of short chain fatty acids but interest is increasing regarding its prebiotic potential. There is also increasing interest in using RS to lower the energy value and available carbohydrate content of foods. RS can also be used to enhance the fibre content of foods and is under investigation regarding its potential to accelerate the onset of satiation and to lower the glycaemic response. Due to the difficulties in agreeing on a universal definition and method of analysis for dietary fibre, RS may be included within the term ‘fibre’ on the nutrition labels in some countries but not in others. Pressure to agree a legal definition and universal method of analysis is likely to increase due to the potential of RS to enhance colonic health, and to act as a vehicle to increase the total dietary fibre content of foodstuffs, particularly those which are low in energy and/or in total carbohydrate content.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-3010.2005.00481.x

Health properties of resistant starch

Cereals high in amylose content (AC) and resistant starch (RS) offer potential health benefits. Previous studies using chemical mutagenesis or RNA interference have demonstrated that starch branching enzyme (SBE) plays a major role in determining the fine structure and physical properties of starch. However, it remains a challenge to control starch branching in commercial lines. Here, we use CRISPR/Cas9 technology to generate targeted mutagenesis in SBEI and SBEIIb in rice. The frequencies of obtained homozygous or bi-allelic mutant lines with indels in SBEI and SBEIIb in T0 generation were from 26.7 to 40%. Mutations in the homozygous T0 lines stably transmitted to the T1 generation and those in the bi-allelic lines segregated in a Mendelian fashion. Transgene-free plants carrying only the frame-shifted mutagenesis were recovered in T1 generation following segregation. Whereas no obvious differences were observed between the sbeI mutants and wild type, sbeII mutants showed higher proportion of long chains presented in debranched amylopectin, significantly increased AC and RS content to as higher as 25.0% and 9.8%, respectively, and thus altered fine structure and nutritional properties of starch. Taken together, our results demonstrated for the first time the feasibility to create high-amylose rice through CRISPR/Cas9-mediated editing of SBEIIb.

/pdf/generation-of-high-amylose-rice-through-crispr-cas9-mediated-zccytgzw3e.pdf

Generation of High-Amylose Rice through CRISPR/Cas9-Mediated Targeted Mutagenesis of Starch Branching Enzymes.

Recent studies of the mechanisms determining the rate and extent of starch digestion by α-amylase are reviewed in the light of current widely-used classifications for (a) the proportions of rapidly-digestible (RDS), slowly-digestible (SDS), and resistant starch (RS) based on in vitro digestibility, and (b) the types of resistant starch (RS 1,2,3,4…) based on physical and/or chemical form. Based on methodological advances and new mechanistic insights, it is proposed that both classification systems should be modified. Kinetic analysis of digestion profiles provides a robust set of parameters that should replace the classification of starch as a combination of RDS, SDS, and RS from a single enzyme digestion experiment. This should involve determination of the minimum number of kinetic processes needed to describe the full digestion profile, together with the proportion of starch involved in each process, and the kinetic properties of each process. The current classification of resistant starch types as RS1,2,3,4 should be replaced by one which recognizes the essential kinetic nature of RS (enzyme digestion rate vs. small intestinal passage rate), and that there are two fundamental origins for resistance based on (i) rate-determining access/binding of enzyme to substrate and (ii) rate-determining conversion of substrate to product once bound.

Mechanisms of starch digestion by α-amylase-Structural basis for kinetic properties.

Objective: This study investigated whether postprandial metabolic responses to bread could be lowered by substituting high amylose maize starch for a part of the flour. Design and subjects: Eight healthy subjects consumed test meals of equivalent nutritional composition based on white wheat bread, bread rich in amylose (HAWB) and spaghetti as a breakfast meal. Blood samples were collected to measure insulin and glucose concentration during two hours after consumption. The degree of starch crystallinity was investigated by X-ray diffraction and DSC analysis. Results: HAWB produced low glycaemic (60±18) and insulinaemic (57±20) indexes similar to those of spaghetti (83±46, 61±16). In vitro amylase hydrolysis of the three foods showed that high amylose content in HAWB significantly lowered starch degradation in bread without affecting hydrolysis kinetics. Addition of amylose in dough increased the resistant starch content of HAWB (14% of dry matter). The resistant starch fraction was mainly composed of crystalline amylose (B-type X-ray diffraction pattern, melting temperature 105°C) attributable to native high amylose maize starch incompletely gelatinised during bread-cooking. Conclusions: Bread produced by the substitution of high amylose maize starch for a part of wheat flour showed a low glycaemic index. Resistant starch in HAWB corresponded to native crystalline amylose not gelatinised during normal bread-processing conditions. Sponsorship: Barilla, via Montova 166, 43100, Parma, Italy.

J L Barry

Papers

Bioavailability of starch in bread rich in amylose: metabolic responses in healthy subjects and starch structure