Dietary fibre is a generic term describing non-absorbed plant carbohydrates and small amounts of associated non-carbohydrate components. The main contributors of fibre to the diet are the cell walls of plant tissues, which are supramolecular polymer networks containing variable proportions of cellulose, hemicelluloses, pectic substances, and non-carbohydrate components, such as lignin. Other contributors of fibre are the intracellular storage oligosaccharides, such as fructans.
View Article and Find Full Text PDFWhile dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal.
View Article and Find Full Text PDFPublished meta-analyses indicate significant but inconsistent incident type-2 diabetes(T2D)-dietary glycemic index (GI) and glycemic load (GL) risk ratios or risk relations (RR). It is nowover a decade ago that a published meta-analysis used a predefined standard to identify validstudies. Considering valid studies only, and using random effects dose-response meta-analysis(DRM) while withdrawing spurious results ( < 0.
View Article and Find Full Text PDFA scientific workshop held in the UK explored the potential contribution of traditional dried fruits to public health, identified gaps in the evidence and addressed priorities for research. Presentations considered the categorisation and composition of dried fruits; dried fruit and gastrointestinal health; the polyphenol content of dried fruits and their potential contribution to health; dried fruit and appetite in relation to the psychology of snacking and obesity; dried fruit and dental health including its role as a snack; and conflicts in public health advice for dried fruits. A round table discussion explored the contribution of dried fruit to "five a day" fruit and vegetable intake and fibre intake, whether dried fruits have equivalence with fresh in terms of dietary advice, advice on snacking in relation to dental health and appetite control, informing the public about different types of dried fruits and avoiding consumer confusion, and future research requirements.
View Article and Find Full Text PDFBackground: The aim of the study was to investigate the practice and pattern of smokeless tobacco (SLT) use as well as the knowledge and perception about its ill effects among rural Bangladeshi adolescents.
Methods: A cross-sectional survey was conducted among students aged 13-18 years in two rural secondary schools in Bangladesh in August 2015. Data were collected through a self-administered questionnaire which consists of topics derived from the Social Cognitive Theory and Health Belief Model (personal characteristics, environmental factors, self-efficacy, outcome expectancies, perceived susceptibility, perceived severity, perceived benefits, perceived barriers, and cues to action).
Nutrition
October 2017
Objectives: The potential positive health effects of carob-containing snacks are largely unknown. Therefore, the aims of these studies were to determine the glycemic index (GI) of a carob snack compared with chocolate cookie containing equal amounts of available carbohydrates and to compare the effects of a carob versus chocolate cookie preload consumed as snack before a meal on (a) short-term satiety response measured by subsequent ad libitum meal intake, (b) subjective satiety as assessed by visual analog scales and (c) postprandial glycemic response.
Methods: Ten healthy, normal-weight volunteers participated in GI investigation.
The function of the arabinan and galactan side-chains of pectin remains unknown. We describe 13C NMR experiments designed to yield spectra from the most mobile polymer components of hydrated cell walls isolated from a range of plant species. In pectin-rich cell walls, these corresponded to the pectic side-chains.
View Article and Find Full Text PDFIn the Arabidopsis mutant irx3, truncation of the AtCesA7 gene encoding a xylem-specific cellulose synthase results in reduced cellulose synthesis in the affected xylem cells and collapse of mature xylem vessels. Here we describe spectroscopic experiments to determine whether any cellulose, normal or abnormal, remained in the walls of these cells and whether there were consequent effects on other cell-wall polysaccharides. Xylem cell walls from irx3 and its wild-type were prepared by anatomically specific isolation and were examined by solid-state NMR spectroscopy and FTIR microscopy.
View Article and Find Full Text PDFNative cellulose in higher plants forms crystalline fibrils a few nm across, with a substantial fraction of their glucan chains at the surface. The accepted crystal structures feature a flat-ribbon 21 helical chain conformation with every glucose residue locked to the next by hydrogen bonds from O-3' to O-5 and from O-2 to O-6'. Using solid-state NMR spectroscopy we show that the surface chains have a different C-6 conformation so that O-6 is not in the correct position for the hydrogen bond from O-2.
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