Soluble and insoluble fibers in ostrich nutrition: influences on growth performance and blood biochemical indices during different ages.

This experiment was undertaken to evaluate the effects of different levels of soluble and insoluble fibers on growth performance and blood indices in ostrich at the age of 1 to 6 months. Thirty 30-day-old ostriches (males and females) were randomly assigned to five treatments with six replicates. There were five dietary treatments consisted of (1) basal diet; (2 and 3) diets containing 2 and 4% more soluble fibers (SF) than basal diet, and (4 and 5) diets containing 2 and 4% more insoluble fibers (ISF) than the basal diet. The dietary treatments had no significant influence on growth performance of ostriches. By increasing the levels of SF and ISF, the concentration of blood glucose (P < 0.0001) and high-density lipoprotein (HDL, P = 0.0046) increased, while the plasma concentration of triglyceride (P < 0.0001) and very-low-density lipoprotein (VLDL, P = 0.0006) decreased. The plasma enzyme activity of alanine aminotransferase (ALT) decreased in ostriches fed diet containing 4% more SF as compared with control (P < 0.0006). Body weight gain (BWG) at the starter phase (3-4 months) was higher than the pre-starter (1-2 months) and grower (5-6 months) phases (P < 0.0001). The highest concentration of blood glucose was observed at 2 months of age while the lowest magnitude was found at 4 months of age (P < 0.0001). The plasma cholesterol concentration increased at 4 months and decreased at 6 months as compared with 2 months (P < 0.0001). The concentration of HDL and LDL at 4 months of age was higher than two other ages (P < 0.0001). The blood concentration of triglyceride (P < 0.0001), VLDL (P < 0.0001), and ALT (P = 0.0005) decreased as ostriches grew up. It could be concluded that increasing the levels of soluble and insoluble fibers in the diet up to 4% more than previous recommendation may not have negative effects on growth performances and blood indices in ostrich.

Recomendaciones y efectos de la fibra dietaria en niños / Recommendations and effects of dietary fiber for children

Conocida es la influencia de la fibra dietaria sobre los efectos mecánicos a nivel gastrointestinal, la composición y modulación de la microbiota intestinal y su función en la actividad metabólica y nutricional en adultos. En niños y adolescentes estos efectos son menos conocidos, generando interesantes áreas de investigación y desarrollo científico que nos puedan entregar mayor conocimiento de sus repercusiones a nivel fisiológicos y fisiopatológicos. Esta revisión tiene como objetivo entregar información actualizada sobre las diferentes clasificaciones de fibra, sus principales funciones digestivas y metabólicas, así como las recomendaciones de ingesta diaria en pediatría.

Among adults, the influence of dietary fiber on mechanical effects at the gastrointestinal level, the composition and modulation of the intestinal microbiota and function in the metabolic and nutritional activity is known. However, in children and adolescents, these effects are less known, generating interesting areas of research and development that could provide additional knowledge at the physiological and pathophysiological level. The aim of this review was to provide updated information about the different classifications of fiber, the principal digestive and metabolic functions, as well as recommendations for daily intake for pediatric populations.

Development of feed composition tables using a statistical screening procedure.

Millions of feed composition records generated annually by testing laboratories are valuable assets that can be used to benefit the animal nutrition community. However, it is challenging to manage, handle, and process feed composition data that originate from multiple sources, lack standardized feed names, and contain outliers. Efficient methods that consolidate and screen such data are needed to develop feed composition databases with accurate means and standard deviations (SD). Considering the interest of the animal science community in data management and the importance of feed composition tables for the animal industry, the objective was to develop a set of procedures to construct accurate feed composition tables from large data sets. A published statistical procedure, designed to screen feed composition data, was employed, modified, and programmed to operate using Python and SAS. The 2.76 million data received from 4 commercial feed testing laboratories were used to develop procedures and to construct tables summarizing feed composition. Briefly, feed names and nutrients across laboratories were standardized, and erroneous and duplicated records were removed. Histogram, univariate, and principal component analyses were used to identify and remove outliers having key nutrients outside of the mean ± 3.5 SD. Clustering procedures identified subgroups of feeds within a large data set. Aside from the clustering step that was programmed in Python to automatically execute in SAS, all steps were programmed and automatically conducted using Python followed by a manual evaluation of the resulting mean Pearson correlation matrices of clusters. The input data set contained 42, 94, 162, and 270 feeds from 4 laboratories and comprised 25 to 30 nutrients. The final database included 174 feeds and 1.48 million records. The developed procedures effectively classified by-products (e.g., distillers grains and solubles as low or high fat), forages (e.g., legume or grass-legume mixture by maturity), and oilseeds versus meal (e.g., soybeans as whole raw seeds vs. soybean meal expellers or solvent extracted) into distinct sub-populations. Results from these analyses suggest that the procedure can provide a robust tool to construct and update large feed data sets. This approach can also be used by commercial laboratories, feed manufacturers, animal producers, and other professionals to process feed composition data sets and update feed libraries.

The effects of diets varying in fibre sources on nutrient utilization, stool quality and hairball management in cats.

Pet food companies use fibrous ingredients in cat foods to aid weight and hairball management. Miscanthus grass could be an alternative novel fibre source for cat foods. The objectives of this work were to determine the effects of Miscanthus grass as a fibre source on nutrient utilization, stool quality and hairball management in cats. Dry extruded cat foods (average chemical composition; digestibility trial: 94.54% dry matter-DM, 34.47% crude protein-CP, 11.67% crude fat, 7.06% ash and 13.04% total dietary fibre-TDF; and hairball trial: 94.88% DM, 34.60% CP, 11.30% crude fat, 7.02% ash and 9.77% TDF) were fed to 12 cats for a 9-day (digestibility trial) or 16-day (hairball trial) adaptation period followed by a 5-day total faecal collection period. Digestibility trial was performed as a replicated Latin square design, and the hairball trial was performed as a switchback design. In general, the cats fed the beet pulp diet (BPD) had higher DM, organic matter, gross energy and TDF digestibility than cats fed Miscanthus grass (MGD) or cellulose (CED) diet (p < .05). However, CP digestibility was lower for cats fed BPD (82.1 vs. 84.7 and 85.1%, respectively, for BPD, MGD and CED). These differences could be due to the differences in dietary fibre content and(or) composition. Faecal scores were lower for cats fed BPD (2.84) compared with MGD (3.32) and CED (3.21; p < .05). No effects due to fibre were reported on the faecal hairball variables, with the exception of less total hair weight and hair clumps per gram of dry faeces for cats fed Miscanthus grass (MGH) compared with control diet (COH; p < .05). In conclusion, Miscanthus grass could be used as an alternative ingredient to cellulose in cat diets.

Alpha-cyclodextrin as a new functional ingredient in low-fat chicken frankfurter.

1. The current consumer preference for healthier meat products is associated with less additives in manufacturing (so-called 'clean-label') or the addition of non-meat ingredients with functional properties, recognised as improving specific technological properties in meat products.2. This study evaluated the effect of the addition of alpha-cyclodextrin and wheat fibre to low-fat chicken frankfurters containing 35% mechanically deboned chicken meat on the technological and sensorial properties during refrigerated storage.3. The results showed that the addition of dietary fibres (alpha-cyclodextrin and wheat fibre) in low-fat chicken frankfurters improved emulsion stability, hardness, chewiness and reduced cohesiveness.4. Alpha-cyclodextrin helped the retention of fat globules in the microstructure and affected colour in the sensorial evaluation.5. The use of alpha-cyclodextrin, in combination with wheat fibre, as a new ingredient to substitute fat in emulsified meat products containing mechanically deboned chicken, improved emulsion stability and texture.6. Alpha-cyclodextrin and wheat fibre were effective in contributing to fat reduction without affecting the sensory properties of the product.

Effect of fiber source and particle size on chick performance and nutrient utilization.

The addition of fiber in chick feeds is known to dilute nutrients; as a result, this may reduce nutrient digestibility and performance. However, recent studies suggest that moderate inclusion of insoluble fibers (2 to 3%) may stimulate gizzard development, which could result in better nutrient utilization and chick growth. The previous fiber sources evaluated were subject to wide fluctuation in their nutritional and chemical composition due to variation in processing. Miscanthus giganteus is a C4 grass purposefully grown for its fiber content which has a consistent fiber composition compared to food process residues. The objectives of this study were to determine the effect of dietary fiber source and particle size on day-old chick performance and nutrient digestibility. Day-old chicks (8 chicks per cage, 5 cages per treatment) were fed diets containing 3% of either sepiolite (SEP), cellulose (CEL), coarse beet pulp (BP), fine BP, coarse Miscanthus grass (MG), and fine MG. At the end of days 7, 14, and 21, chicks and experimental diets were weighed to compute average daily gain and feed intake. In addition, excreta from the previous 48 h of each data capture point was collected to determine nutrient digestibility. In general, chicks fed diets containing fiber consumed more feed, gained more weight, and had better feed conversion rate than birds fed the SEP diet. Particle size of the fiber had no effect on chick performance; however, nutrient utilization was higher (P < 0.05) for chicks fed coarse fiber particles compared to these fed fine fiber particles. Birds fed diets containing MG performed similar to chicks fed CEL (P > 0.05), but digestibility coefficients of birds fed BP diets were generally higher than chicks fed MG diets. In conclusion, chicks performed better with fiber in their diet and MG was comparable to CEL.

Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health.

Research into the analysis, physical properties and health effects of dietary fibre has continued steadily over the last 40-50 years. From the knowledge gained, countries have developed guidelines for their populations on the optimal amount of fibre to be consumed each day. Food composition tables from many countries now contain values for the dietary fibre content of foods, and, from these, combined with dietary surveys, population intakes have been determined. The present review assessed the uniformity of the analytical methods used, health claims permitted, recommendations and intakes, particularly from national surveys across Europe and around the world. It also assessed current knowledge on health effects of dietary fibre and related the impact of different fibre types on health. The overall intent was to be able to provide more detailed guidance on the types of fibre which should be consumed for good health, rather than simply a total intake figure, the current situation. Analysis of data indicated a fair degree of uniformity in the definition of dietary fibre, the method used for analysis, the recommended amount to be consumed and a growing literature on effects on digestive health and disease risk. However, national dietary survey data showed that intakes do not reach recommendations and very few countries provide guidance on the types of fibre that are preferable to achieve recommended intakes. Research gaps were identified and ideas suggested to provide information for more detailed advice to the public about specific food sources that should be consumed to achieve health benefits.

Fibra dietaria: nuevas definiciones, propiedades funcionales y beneficios para la salud: revisión / Dietary fiber: new definitions, functional properties and health benefits

En los últimos diez años hubo importantes modificaciones en la definición de la fibra dietaria bajo la dirección de la Comisión del CODEX Alimentarius. El más importante fue la inclusión de los carbohidratos no digeribles de 3 a 9 unidades de grado de polimerización dentro de la definición química, la que fue adoptada algunos países y en otras están en proceso de evaluación tal como los Estados Unidos; lo que hace que no exista un consenso global. Donde sí hay un consenso es en la definición fisiológica de la fibra dietaria, considerada como grupo de carbohidratos resistentes a la digestión por las enzimas del intestino delgado y fermentado en forma parcial o total en el colon, con efectos favorables en la salud. La Association of Official Analytical Chemist (siglas en Inglés: AOAC), en armonía con la nueva definición del CODEX Alimentarius, establecieron los métodos AOAC 2009.01 y 2011.25, diseñado para cuantificar la fibra dietaria solubles, fibra dietaria insoluble y la fibra dietaria total. En este contexto, se vienen desarrollando investigaciones in vitro e in vivo (en animales y humanos) para demostrar los efectos fisicoquímicos, funcionales y fisiológicos que van orientados hacia la prevención y tratamiento de algunas enfermedades no transmisible (ENTs). La presente revisión, pretende informar de las nuevas definiciones y los métodos de análisis, las propiedades funcionales y fisiológicas de la fibra dietaria y sus efectos en la salud humana(AU)

In the last ten years there have been important changes in the definition of dietary fiber under the leadership of the CODEX Alimentarius Commission. The most important was the inclusion of non-digestible carbohydrates of 3 to 9 units of degree of polymerization within the chemical definition, which was adopted in some countries and in others are in the process of evaluation such as the United States which indicates that does not exist a global consensus. Where there is a consensus is in the physiological definition of dietary fiber, considered as a group of carbohydrates resistant to the digestion by enzymes of the small intestine and fermented partially or totally in the colon, with favorable health effects. The Association of Official Analytical Chemists (AOAC), in line with the new definition of CODEX Alimentarius, established the AOAC 2009.01 and 2011.25 methods, designed to quantify soluble dietary fiber, insoluble dietary fiber and total dietary fiber. In this context, In Vitro and In Vivo research (in animals and humans) are being carried out to demonstrate the physicochemical, functional and physiological effects that are directed towards the prevention and treatment of some non-communicable diseases (NCDs). This review aims to inform the new definitions and methods of analysis, the functional and physiological properties of dietary fiber and their effects on human health(AU)

Forage intake and weight gain of ewes is affected by roughage mixes during winter in northeastern China.

We studied the effect of dietary roughage species and their combinations on forage intake and growth rate of ewes during winter in a pastoral-farming area of northeast China. Twenty-five Northeast crossbred ewes (fine-wool sheep × Small-tailed Han sheep) were randomly selected and divided into five groups (G1, G2, G3, G4 and G5). During a 30 day feeding trial, each group of ewes were offered the same basal diet (composed of 0.36 kg chopped maize stalk (10 mm), 0.14 kg corn meal, 0.05 kg soybean meal and 1.2 g NaCl) and one of the five supplementary roughage mixes, namely 100% Leymus chinensis hay (G1), 100% Vigna radiata stalk (G2), L. chinensis hay plus Suaeda glauca (G3), V. radiata stalk plus S. glauca (G4) and L. chinensis hay plus V. radiata stalk and S. glauca (G5). The results showed that roughage mixes had significant influences on daily roughage intake and daily weight gain of ewes. Ewes had greater daily roughage intake when supplemented with three species of roughage compared to the roughage with one species; however, there was no significant difference between G1 and G2, G3 and G4, or between G4 and G5. The average daily gain of ewes was also greater when they were supplemented with the roughage combination of L. chinensis, V. radiata stalk and S. glauca. No difference in average daily weight gain was observed between the G4 and G5 treatments (P > 0.05). The lowest average daily weight gain was observed when the ewes were supplemented with V. radiata stalk alone (G2) (P < 0.05). The results indicated that supplying ewes with various roughages simultaneously in winter could improve their forage intake and average daily weight gain compared to offering the ewes only one type of dietary roughage. Further, feeding roughage supplements containing a diverse mix of roughage species represents one method for increasing roughage utilization in livestock production during winter in the pastoral-farming areas of northeastern China.

New Horizons for the Study of Dietary Fiber and Health: A Review.

Dietary fibre has been consumed for centuries with known health benefits, but defining dietary fibre is a real challenge. From a functional perspective, dietary fibre is described as supporting laxation, attenuating blood glucose responses and assisting with cholesterol lowering. The problem is different types of dietary fibre have different effects, and new effects are increasingly observed, such as the influence on gut microbiota. Thus, a single definition may need to be described in more generic terms. Rather than being bound by a few functional definitions, we may need to embrace the possibilities of new horizons, and derive a working definition of dietary fibre based on a set of conceptual principles, rather than the limited definitions we have to date. To begin this process, a review of individual fibre types and their physiological effects would be helpful. Dietary fibre is a complex group of substances, and there is a growing interest in specific effects linked to fibre type. Different fractions of dietary fibre have different physiological properties, yet there is a paucity of literature covering the effects of all fibres. This paper describes a range of individual fibre types and identifies gaps in the literature which may expose new directions for a working definition of dietary fibre.

A Critical Look at Prebiotics Within the Dietary Fiber Concept.

This article reviews the current knowledge of the health effects of dietary fiber and prebiotics and establishes the position of prebiotics within the broader context of dietary fiber. Although the positive health effects of specific fibers on defecation, reduction of postprandial glycemic response, and maintenance of normal blood cholesterol levels are generally accepted, other presumed health benefits of dietary fibers are still debated. There is evidence that specific dietary fibers improve the integrity of the epithelial layer of the intestines, increase the resistance against pathogenic colonization, reduce the risk of developing colorectal cancer, increase mineral absorption, and have a positive impact on the immune system, but these effects are neither generally acknowledged nor completely understood. Many of the latter effects are thought to be particularly elicited by prebiotics. Although the prebiotic concept evolved significantly during the past two decades, the line between prebiotics and nonprebiotic dietary fiber remains vague. Nevertheless, scientific evidence demonstrating the health-promoting potential of prebiotics continues to accumulate and suggests that prebiotic fibers have their rightful place in a healthy diet.

[Fiber-type indication among different pathologies]. / INDICACIONES DE DIFERENTES TIPOS DE FIBRA EN DISTINTAS PATOLOGÍAS.

INTRODUCTION: Fiber definition includes all those carbohydrates which are not digested nor absorbed in the upper gastrointestinal tract allowing them to reach the colon with no previous processing. Traditionally fiber has been classified according to their solubility into soluble and insoluble and different physiological properties have been defined for each type. The physiologic role of the fiber intake has been studied in diabetes, dyslipidemia or obesity. Fiber intake has also demonstrated to be beneficial in the prevention of many neoplastic diseases like colorectal cancer. It´s also known that fiber plays an important role in the faecal excretion of nitrogen. AIM: To evaluate the current evidence that fiber intake plays in the management and prevention of several different diseases, being able to determine, if possible, the most recommended fiber type for each clinical condition. METHODS: A non-systematic review by searching the Medline and Pubmed was made and studies which met the inclusion criteria were identified and selected for analysis. RESULTS: Different fiber types can be useful for the treatment of several gastrointestinal diseases like constipation, diarrhea, irritable bowel syndrome, ulcerative colitis remission or short bowel syndrome. Patients diagnosed with diabetes, obesity, hyperlipidemia, hypertension and other cardiometabolic diseases can get a clinical improvement with soluble fiber intake. Dietary fiber has demonstrated to play a role in the prevention of colorrectal cancer and other neoplastic diseases. Patients with hepatic encephalopathy or chronic kidney disease will also benefit from fermentable fiber intake. DISCUSSION: Fiber plays an important role in the prevention and treatment of many clinical conditions. However further investigations are needed to establish specific fiber intake recommendations.

Introducción: la fibra engloba los carbohidratos no digeridos ni absorbidos en el tubo digestivo, llegando intactos al colon. Se clasifica en soluble e insoluble, con propiedades fisiológicas distintas. La fibra se ha empleado frecuentemente para tratar y prevenir diversas patologías gastrointestinales. También se ha estudiado su papel en la fisiopatología de enfermedades como la diabetes, la dislipemia, la hipertensión arterial y la obesidad. Además se ha relacionado su consumo con la prevención de ciertos tumores, en especial del cáncer colorrectal, así como con el aumento de la excreción de nitrógeno en heces. Objetivos: analizar la evidencia del papel que la fibra puede tener en el tratamiento y prevención de distintas enfermedades, así como el tipo de fibra más adecuado en cada una. Métodos: revisión no sistemática en Medline y Pubmed, y posterior aplicación de los criterios de inclusión y exclusión. Resultados: diferentes tipos de fibra pueden ser útiles en el tratamiento de enfermedades gastrointestinales, como el estreñimiento, la diarrea, el síndrome de intestino irritable, la colitis ulcerosa en remisión o el síndrome de intestino corto. Los pacientes con diabetes, obesidad, hiperlipidemia, hipertensión y enfermedad cardiovascular también pueden beneficiarse del consumo principalmente de fibra soluble. La fibra alimentaria ha demostrado prevenir el cáncer de colon y otros tumores. En pacientes con encefalopatía hepática o insuficiencia renal, la fibra fermentable ha demostrado beneficios. Conclusiones: la fibra tiene un papel importante en la prevención y tratamiento de múltiples enfermedades; sin embargo, son necesarios más estudios de calidad para poder realizar recomendaciones más específicas.

Animal fibre: the forgotten nutrient in strict carnivores? First insights in the cheetah.

As wild felids are obligate carnivores, it is likely that poorly enzymatically digestible animal tissues determine hindgut fermentation, instead of plant fibre. Therefore, faecal concentrations of short-chain fatty acids (SCFA, including branched-chain fatty acids, BCFA), indole and phenol were evaluated in 14 captive cheetahs, fed two different diets differing in proportion of poorly enzymatically digestible animal tissue. Using a cross-over design, the cheetahs were fed exclusively whole rabbit or supplemented beef for 1 month each. Feeding whole rabbit decreased faecal propionic (p < 0.001) and butyric (p = 0.013) acid concentrations, yet total SCFA was unaltered (p = 0.146). Also, a remarkably higher acetic acid to propionic acid ratio (p = 0.013) was present when fed whole rabbit. Total BCFA (p = 0.011) and putrefactive indole (p = 0.004) and phenol (p = 0.002) were lower when fed whole rabbit. Additionally, serum indoxyl sulphate, a toxic metabolite of indole, was analysed and showed a quadratic decrease (p = 0.050) when fed whole rabbit. The divergent SCFA ratios and the decrease in putrefaction when fed whole rabbit could be caused by the presence of undigested tissue, such as skin, bone and cartilage, that might have fibre-like functions. The concept of animal fibre is an unexplored area of interest relevant to gastrointestinal health of captive cheetahs and likely other felids.

Electromyographic evaluation of masseter muscle activity in horses fed (i) different types of roughage and (ii) maize after different hay allocations.

The aims of this study were to monitor electromyographic (EMG) activity of masseter muscle in healthy horses fed (i) different types of roughage and (ii) maize after different hay allocations. Four horses were offered the following three diets ad libitum: hay, haylage or straw/alfalfa chaff (SAC). In a second trial, four horses were fed cracked maize (CM) and hay in three different orders: (i) CM after a 12-h overnight fast; (ii) CM immediately after restricted hay intake (0.6 kg hay/100 kg BW); or 3) CM after hay intake ad libitum. The activity of the masseter muscle was determined by EMG (IED(®) ), and the following were measured: amplitude (muscle action potential = MAP, maximum voltage) and duration of MAP (s). The intake of hay or haylage was associated with intense masseter muscle activity (MAP: hay, 10 ± 1.7 V; haylage, 11 ± 3.3 V; and duration of MAP: hay, 0.31 ± 0.04 s; haylage, 0.30 ± 0.04 s). Similar intense chewing was measured for SAC (MAP 13 ± 3.8 V), although duration of the chewing cycle was relatively short (0.22 ± 0.03 s, diet p < 0.05), which is possibly related to the shorter fibre length. CM was consumed rapidly, with less intense masseter muscle activity (MAP 6.0 ± 1.5 V). Hay intake before CM did not affect chewing force of CM, but duration of chewing cycle was significantly prolonged by feeding hay ad libitum before CM was fed. The consumption of hay, haylage or SAC was associated with intensive masseter muscle activity that was likely to stimulate salivary flow rate. In contrast to roughage, concentrates like CM are consumed rapidly with less intensive masseter muscle activity. This situation is associated with a low salivary flow that may have an adverse effect on gastric function.

Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits.

PURPOSE: This review focuses on the health benefits of viscous versus nonviscous soluble fibers, why symptoms can occur with increased fiber consumption, and how to avoid symptoms to improve adherence with a high-fiber diet. DATA SOURCES: Review of scientific literature as well as evidence-based guidelines and resources. CONCLUSIONS: While it is generally known that "fiber is good for you," it is less well known that specific health benefits are associated with specific fiber characteristics. Many of the health benefits of fiber can be directly correlated with the viscosity of soluble fibers when hydrated (i.e., gel-forming). A reduction in viscosity of a given fiber will attenuate these health benefits, and a nonviscous fiber does not exhibit these health benefits. IMPLICATIONS FOR PRACTICE: Increasing the viscosity of chyme with a viscous soluble fiber has been shown clinically to lower cholesterol for cardiovascular health, improve glycemic control in type 2 diabetes, normalize stool form in both constipation (softens hard stool) and diarrhea (firms loose/liquid stool), and improve the objective clinical measures of metabolic syndrome (glycemic control, lipoprotein profile, body mass index/weight loss, and blood pressure).

The glycemic response does not reflect the in vivo starch digestibility of fiber-rich wheat products in healthy men.

Starchy food products differ in the rate of starch digestion, which can affect their metabolic impact. In this study, we examined how the in vivo starch digestibility is reflected by the glycemic response, because this response is often used to predict starch digestibility. Ten healthy male volunteers [age 21 ± 0.5 y, BMI 23 ± 0.6 kg/m² (mean ± SEM)] participated in a cross-over study, receiving three different meals: pasta with normal wheat bran (PA) and bread with normal (CB) or purple wheat bran (PBB). Purple wheat bran was added in an attempt to decrease the rate of starch digestion. The meals were enriched in ¹³C and the dual isotope technique was applied to calculate the rate of appearance of exogenous glucose (RaE). The ¹³C-isotopic enrichment of glucose in plasma was measured with GC/combustion/isotope ratio MS (IRMS) and liquid chromatography/IRMS. Both IRMS techniques gave similar results. Plasma glucose concentrations [2-h incremental AUC (iAUC)] did not differ between the test meals. The RaE was similar after consumption of CB and PBB, showing that purple wheat bran in bread does not affect in vivo starch digestibility. However, the iAUC of RaE after men consumed PA was less than after they consumed CB (P < 0.0001) despite the similar glucose response. To conclude, the glycemic response does not always reflect the in vivo starch digestibility. This could have implications for intervention studies in which the glycemic response is used to characterize test products.

Effects of dietary fibre on subjective appetite, energy intake and body weight: a systematic review of randomized controlled trials.

Dietary fibres are believed to reduce subjective appetite, energy intake and body weight. However, different types of dietary fibre may affect these outcomes differently. The aim of this review was to systematically investigate the available literature on the relationship between dietary fibre types, appetite, acute and long-term energy intake, and body weight. Fibres were grouped according to chemical structure and physicochemical properties (viscosity, solubility and fermentability). Effect rates were calculated as the proportion of all fibre-control comparisons that reduced appetite (n = 58 comparisons), acute energy intake (n = 26), long-term energy intake (n = 38) or body weight (n = 66). For appetite, acute energy intake, long-term energy intake and body weight, there were clear differences in effect rates depending on chemical structure. Interestingly, fibres characterized as being more viscous (e.g. pectins, ß-glucans and guar gum) reduced appetite more often than those less viscous fibres (59% vs. 14%), which also applied to acute energy intake (69% vs. 30%). Overall, effects on energy intake and body weight were relatively small, and distinct dose-response relationships were not observed. Short- and long-term effects of dietary fibres appear to differ and multiple mechanisms relating to their different physicochemical properties seem to interplay. This warrants further exploration.