Interventions to lower the glycemic response to carbohydrate foods with a low-viscosity fiber (resistant maltodextrin): meta-analysis of randomized controlled trials

Postprandial glycemic response to a high-protein diabetes-specific nutritional shake compared to isocaloric instant oatmeal in people with type 2 diabetes: a randomized, controlled, crossover trial

Introduction

Minimizing postprandial glucose response is an important goal for overall diabetes management. Diabetes-specific nutritional shakes (DSNS) have been clinically shown to minimize postprandial glucose response in people with type 2 diabetes (T2DM) compared to high-glycemic foods. However, it is unknown how a high-protein, low-fat DSNS impacts the GLP-1 response.

Methods

We tested the postprandial glucose, insulin, and GLP-1 response to a high-protein, low-fat diabetes-specific nutritional shake (DSNS-HP) compared to isocaloric instant oatmeal (IOM) in a randomized, controlled, crossover study in adults with T2DM (n = 24). Participants were randomly selected to receive IOM or DSNS-HP on two test days. Glucose, insulin, and total GLP-1 concentration were measured at baseline and 15, 30, 45, 60, 90, 120, 180, and 240 min postprandially.

Results

Compared to IOM, the glucose-positive area under the curve (pAUC) was significantly lower (P = .021). DSNS-HP significantly increased GLP-1 pAUC response by 213% (P <.001) with a corresponding increase in insulin pAUC (P = .033) compared to IOM.

Discussion

A high-protein, low-fat DSNS leads to favorable changes in GLP-1 response and is a suitable option to minimize blood glucose response in people with type 2 diabetes.

Stability of vitamin C, carotenoids, phenols, and antioxidant capacity of pasteurised orange juice with resistant maltodextrin storage

Resistant maltodextrin (RMD) was added at increasing concentrations (0%, 2.5%, 5% and 7.5%) before pasteurisation to orange juice to analyse its potential protective effect on the health-related bioactive compounds of pasteurised orange juice throughout its storage time. Samples were characterised in terms of basic physico-chemical properties and bioactive compounds at the beginning of the storage. Higher concentrations of RMD proved to better preserve the bioactive compounds of orange juice, thus obtaining a higher antioxidant capacity (AC). Stability of all samples was determined by measuring the same parameters at days 0, 15, 45, 75, 105, 136 and 170 of storage. °Brix and pH were very stable in all samples along storage, while all bioactive compouds had negative variations. However, RMD addition slightly improved ascorbic acid, vitamin C, total phenols, and total carotenoids retention, improving then its AC. This effect was greater in the 5% RMD-added samples. All bioactive compounds showed a positive Pearson's correlation coefficient with AC. Colour variations were also measured at days 105 and 170. All samples had a positive variation of all colour parameters, being this clearer at day 170. This work enlights the potential functionality of RMD to better preserve the health-related compounds of pasteurised orange juice.

Sensory Evaluation, Physico-Chemical Properties, and Aromatic Profile of Pasteurised Orange Juice with Resistant Maltodextrin

The beneficial health effects of prebiotics have been demonstrated in numerous research papers. However, their incorporation into daily food remains unfamiliar to consumers. This work evaluates the effects of the addition of resistant maltodextrin (RMD) on the sensory attributes of pasteurised orange juice, together with the physico-chemical properties and the aromatic profile. RMD addition increased the sweetness and decreased the acidity and bitterness, resulting in a higher overall panellists' rating of orange juice. It also proportionally increased °Brix together with density and decreased acidity. Colour changes were registered with higher RMD concentrations. Orange pulp presence affected the volume particle size distribution analysis, while RMD addition did not have any effect. The aroma volatile compounds were also analysed. Pulp-added samples showed a higher quantity of alcohol and aldehydes, whereas pulp-free samples registered higher terpene and terpenoid values. Ketones and acids were also quantified. RMD had a moderate impact on volatile compound quantifications, with the orange pulp presence playing a much more decisive role. A correspondence analysis was also performed to relate instrumental and sensory determinations for all samples. This work proves that the addition of RMD to orange juice is technologically feasible while also achieving a good response at the sensory level.

A Novel Powder Formulation of the Ketone Ester, Bis Hexanoyl (R)-1,3-Butanediol, Rapidly Increases Circulating ß-Hydroxybutyrate Concentrations in Healthy Adults

Objective: Growing interest in the metabolic state of ketosis has driven development of exogenous ketone products to induce ketosis without dietary changes. Bis hexanoyl (R)-1,3-butanediol (BH-BD) is a novel ketone ester which, when consumed, increases blood beta-hydroxybutyrate (BHB) concentrations. BH-BD is formulated as a powder or ready-to-drink (RTD) beverage; the relative efficacy of these formulations is unknown, but hypothesized to be equivalent.Methods: This randomized, observer-blinded, controlled, crossover decentralized study in healthy adults (n = 15, mean age = 33.7 years, mean BMI = 23.6 kg/m2) aimed to elucidate blood BHB and glucose concentrations before and 15, 30, 45, 60, 90 and 120 minutes following two serving sizes of reconstituted BH-BD powder (POW 25 g, POW 12.5 g), compared to a RTD BH-BD beverage (RTD 12.5 g), and a non-ketogenic control, all taken with a standard meal.Results: All BH-BD products were well tolerated and increased BHB, inducing nutritional ketosis (BHB ≥0.5 mM) after ∼15 minutes, relative to the control. BHB remained elevated 2 h post-consumption. The control did not increase BHB. Ketosis was dose responsive; peak BHB concentration and area under the curve (AUC) were two-fold greater with POW 25 g compared to POW 12.5 g and RTD 12.5 g. There were no differences in peak BHB and AUC between matched powder and RTD formulas. Blood glucose increased in all conditions following the meal but there were neither significant differences in lowest observed concentrations, nor consistent differences at each time point between conditions. These results demonstrate that both powdered and RTD BH-BD formulations similarly induce ketosis with no differences in glucose concentrations in healthy adults.

Optimization of spray drying process of Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder using nondigestible maltodextrin by response surface methodology (RSM)

The optimal spray-drying conditions for manufacturing Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder (JAJP) using response surface methodology (RSM) were investigated. The optimization was performed using two independent factors, which are inlet air temperature (130-180 °C) and different concentrations of nondigestible maltodextrin (NMD) as a carrier agent (10-30%). Responses such as drying yield, moisture content, water solubility index (WSI), bulk density, color, pH, and antioxidant activities of JAJP were investigated. Moisture content, vitamin C content, color, antioxidant activity, pH and bulk density were greatly influenced by inlet air temperature, but dry yield and WSI were only significantly affected by NMD concentration. The optimum spray drying conditions were determined as 14.7% NMD concentration and 154.5 °C inlet air temperature, respectively. At these optimum conditions, a drying yield of 55.73%, 4.84% moisture content, 90.98% WSI, 0.59 g/mL of bulk density, and 169.87 mg/g vitamin C content in JAJP were measured. Therefore, JAJP with the desirable physicochemical properties could be produced.

Is Fibersol-2 efficacious in reducing duration of watery diarrhea and stool output in children 1-3 years old? A randomized, parallel, double-blinded, placebo-controlled, two arm clinical trial

BACKGROUND

Fibersol-2 has innumerable beneficial effects on human health. It is a fermentable, non-viscous, water-soluble, indigestible dextrin containing 90% dietary fiber produced from corn starch. We aimed to evaluate whether additional intake of Fibersol-2 along with oral rehydration solution treatment can reduce the duration of watery diarrhea and daily stool output in children 1-3 years as well as recovery of such children within 72 hours, compared to placebo.

METHODS

This placebo-controlled double-blinded, randomized parallel two arm trial conducted in Kumudini Women's Medical College Hospital in rural Bangladesh between March and October, 2018 used 5 gm of either Fibersol-2 or placebo dissolved in 50-ml drinking water which was given orally to ninety-two children with watery diarrhea on enrollment twice daily for a period of 7 days. Randomization was done using a randomization table. We randomly allocated 45 (49%) and 47 (51%) children in Fibersol-2 and placebo groups, respectively. Outcome measures were duration of resolution of watery diarrhea, daily stool output and the proportion of children recovered within 72 hours. Primary and safety analyses were by intention to treat. This trial was registered at ClinicalTrials.gov, number NCT03565393.

RESULTS

There was no significant difference observed in terms of duration of resolution of diarrhea (adjusted mean difference 8.20, 95% CI -2.74 to 19.15, p = 0.14, adjusted effect size 0.03); the daily stool output (adjusted mean difference 73.57, 95% CI -94.17 to 241.32, p = 0.38, adjusted effect size 0.33) and the proportion of children recovered within 72 hours (adjusted odds ratio 0.49, 95% CI = 0.12 to 1.96, p = 0.31, adjusted risk difference -0.06 (95% CI -0.19 to -0.06), after regression analysis between Fibersol-2 and placebo.

CONCLUSION

No beneficial role of Fibersol-2 was observed in diarrheal children aged 1-3 years.

TRIAL REGISTRATION

This trial is registered at ClinicalTrials.gov, number NCT03565393. The authors confirmed that all ongoing and related trials for this drug/intervention are registered. https://clinicaltrials.gov/ct2/show/NCT03565393.

The Effects of Soluble Dietary Fibers on Glycemic Response: An Overview and Futures Perspectives

The properties of each food, composition, and structure affect the digestion and absorption of nutrients. Dietary fiber (DF), especially viscous DF, can contribute to a reduction in the glycemic response resulting from the consumption of carbohydrate-rich foods. Target and control of postprandial glycemic values are critical for diabetes prevention and management. Some mechanisms have been described for soluble DF action, from the increase in chyme viscosity to the production of short-chain fatty acids resulting from fermentation, which stimulates gastrointestinal motility and the release of GLP-1 and PYY hormones. The postprandial glycemic response due to inulin and resistant starch ingestion is well established. However, other soluble dietary fibers (SDF) can also contribute to glycemic control, such as gums, β-glucan, psyllium, arabinoxylan, soluble corn fiber, resistant maltodextrin, glucomannan, and edible fungi, which can be added alone or together in different products, such as bread, beverages, soups, biscuits, and others. However, there are technological challenges to be overcome, despite the benefits provided by the SDF, as it is necessary to consider the palatability and maintenance of their proprieties during production processes. Studies that evaluate the effect of full meals with enriched SDF on postprandial glycemic responses should be encouraged, as this would contribute to the recommendation of viable dietary options and sustainable health goals.

Digestive tolerability and acceptability of Fibersol-2 in healthy and diarrheal children 1–3 years old at a rural facility, Bangladesh: Results from a four arm exploratory study

Background

Fibersol-2 has some beneficial effects on human health. We aimed to evaluate the digestive tolerability and acceptability of Fibersol-2 in healthy and diarrheal children, as well as improvement in stool consistencies in young diarrheal children.

Methods

Sixty children of either sex, aged 1–3 years having four groups (healthy children/low dose, healthy children/high dose, children with diarrhea/low dose and children with diarrhea/high dose) were enrolled into this exploratory study between 1st August to 23rd October 2017. Two presumptive doses, low (2.5g) and high (5g), twice daily with 50 ml drinking water for seven days were the interventions. Outcomes were to observe the development of possible abdominal symptoms, such as pain, distension, rumbling, and bloating during the intervention and post-intervention periods in healthy and diarrheal children as well as improvement in stool consistencies in diarrheal children.

Results

Among the diarrheal children, the median (IQR) duration of resolution of diarrhea was 3.9 (2.9, 5.1) days vs. 3.5 (2.0, 8.0) days, p = 0.885; in low dose and high dose groups, respectively. Significant difference was observed in terms of abdominal pain (27% vs. 7%, p = 0.038) and distension (40% vs. 0%, p<0.001) in diarrheal children, compared to healthy children during the pre-intervention period. We also observed significant difference in respect of abdominal distension (23% vs. 0%, p = 0.011), rumbling (27% vs. 0%, p = 0.005) and bloating (43% vs. 3%, p = 0.001) in diarrheal children, compared to healthy children during the intervention period. However, no significant difference was observed in relation to abdominal pain (p = 0.347) and distension (p = 0.165) during the pre-intervention period, compared to the intervention period in diarrheal children. Moreover, no significant difference was observed during the post-intervention period for the diarrheal and healthy children.

Conclusion

Fibersol-2 was found to be well tolerated in healthy and diarrheal children aged 1–3 years.

Trial registration

This study was registered as part of a randomized trial at ClinicalTrials.gov, number NCT03565393. The authors confirmed that all ongoing and related trials for this drug/intervention were registered.

Blood Glucose Response of a Low-Carbohydrate Oral Nutritional Supplement with Isomaltulose and Soluble Dietary Fiber in Individuals with Prediabetes: A Randomized, Single-Blind Crossover Trial

A high-energy-type oral dietary supplement (ONS), with a low proportion of available carbohydrate (LC-ONS), which contains a slowly digestible carbohydrate, isomaltulose, and is fortified with soluble dietary fiber, was newly developed for individuals with diabetes or prediabetes. This study aimed to evaluate the impact of LC-ONS on blood glucose levels after ingestion in individuals with prediabetes. A single-blind, randomized crossover clinical trial was performed on 20 individuals with prediabetes. After overnight fasting, all subjects ingested one serving (200 kcal/125 mL) of either LC-ONS (40% energy proportion of available carbohydrates) or standard ONS (ST-ONS, 54% energy proportion of available carbohydrates) on two separate days. The incremental area under the curve of blood glucose levels for 120 min was significantly lower after LC-ONS ingestion compared to ST-ONS (2207 ± 391 mg/dL·min (least mean square value ± standard error) and 3735 ± 391 mg/dL·min, respectively; p < 0.001). The LC-ONS showed significantly lower blood glucose levels than the ST-ONS at all time points, except at baseline. Similarly, the incremental area under the curve of plasma insulin was significantly lower after LC-ONS ingestion. These results suggest that LC-ONS is useful as an ONS for energy supply in individuals with postprandial hyperglycemia.

Impact of food processing on postprandial glycaemic and appetite responses in healthy adults: a randomized, controlled trial

Chickpeas are among the lowest glycaemic index carbohydrate foods eliciting protracted digestion and enhanced satiety responses. In vitro studies suggest that mechanical processing of chickpeas significantly increases starch digestion. However, there is little evidence regarding the impact of processing on postprandial glycaemic response in response to chickpea intake in vivo. Therefore, the aim of this study was to determine the effect of mechanical processing on postprandial interstitial glycaemic and satiety responses in humans. In a randomised crossover design, thirteen normoglycaemic adults attended 4 separate laboratory visits following an overnight fast. On each occasion, one of four test meals, matched for available carbohydrate content and consisting of different physical forms of chickpeas (whole, puree, and pasta) or control (mashed potato), was administered followed by a subsequent standardised lunch meal. Continuous glucose monitoring captured interstitial glucose responses, accompanied by periodic venous blood samples for retrospective analysis of C-peptide, glucagon like peptide-1 (GLP-1), ghrelin, leptin, resistin, and cortisol. Subjective appetite responses were measured by Visual Analogue Scale (VAS). Postprandial glycaemic responses were comparable between chickpea treatments albeit significantly lower than the control (p < 0.001). Similarly, all chickpea treatments elicited significantly lower C-peptide and GLP-1 responses compared to the control (p < 0.05), accompanied by enhanced subjective satiety responses (p < 0.05), whilst no significant differences in satiety hormones were detected among different intervention groups (p > 0.05). Chickpea consumption elicits low postprandial glycaemic responses and enhanced subjective satiety responses irrespective of processing methods.

Effect of Adding Resistant Maltodextrin to Pasteurized Orange Juice on Bioactive Compounds and Their Bioaccessibility

Resistant maltodextrin (RMD) is a water-soluble and fermentable functional fiber. RMD is a satiating prebiotic, reducer of glucose and triglycerides in the blood, and promoter of good gut health, and its addition to food is increasingly frequent. Therefore, it is necessary to study its potential effects on intrinsic bioactive compounds of food and their bioaccessibility. The aim of this study was to evaluate the effect of adding RMD on the bioactive compounds of pasteurized orange juice with and without pulp, and the bioaccessibility of such compounds. RMD was added at different concentrations: 0 (control sample), 2.5%, 5%, and 7.5%. Ascorbic acid (AA) and vitamin C were analyzed using HPLC, whereas total phenols, total carotenoids (TC), and antioxidant capacity were measured using spectrophotometry. After that, sample in vitro digestibility was assessed using the standardized static in vitro digestion method. The control orange juice with pulp presented significantly higher values of bioactive compounds and antioxidant capacity than the control orange juice without pulp (p < 0.05). RMD addition before the juice pasteurization process significantly protected all bioactive compounds, namely total phenols, TC, AA, and vitamin C, as well as the antioxidant capacity (AC) (p < 0.05). Moreover, this bioactive compound protective effect was higher when higher RMD concentrations were added. However, RMD addition improved phenols and vitamin C bioaccessibility but decreased TC and AA bioaccessibility. Therefore, the AC value of samples after gastrointestinal digestion was slightly decreased by RMD addition. Moreover, orange pulp presence decreased total phenols and TC bioaccessibility but increased AA and vitamin C bioaccessibility.

Impact of Resistant Maltodextrin Addition on the Physico-Chemical Properties in Pasteurised Orange Juice

Resistant maltodextrin (RMD) is a water-soluble fibre that can be fermented in the colon and exert prebiotic effects. Therefore, its addition to food and beverage products could be beneficial from both technological and nutritional viewpoints. However, to date, most studies have focused on the stability of the prebiotic fibre rather than its impact in the original food matrices. Therefore, this work aimed to evaluate the addition of RMD on the physico-chemical properties of pasteurised orange juice (with and without pulp). °Brix, pH, acidity, particle size distribution, density, turbidity, rheology, and colour were measured in orange juices with increasing RMD concentrations (2.5, 5, and 7.5%). Control samples without RMD were also prepared. RMD added soluble solids to the orange juice, affecting the °Brix, density, turbidity, and rheology. Slight colour differences were observed, and lower citric acid content was achieved because of orange juice replacement with RMD. Differences in particle size distribution were exclusively because of pulp content. Further studies are needed to elucidate if potential consumers will appreciate such physico-chemical changes in organoleptic terms.

Visceral Fat-Reducing Effect and Safety of Continuous Consumption of Beverage Containing Resistant Maltodextrin: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Clinical Trial

Obesity is regarded as a global concern with increasing prevalence, most notably in developed countries. Metabolic syndrome is a predictor of cardiovascular disease and type 2 diabetes mellitus and is defined as the accumulation of multiple risk factors caused by abdominal visceral obesity. Resistant maltodextrin (RMD) is a soluble dietary fiber that has been shown to reduce visceral fat in long-term clinical trials when continuously administered at 10 g, three times daily. Herein, we evaluated the effects of long-term consumption of 5 g RMD three times daily. A total of 140 healthy adults were randomly assigned to two intervention groups for a 12-wk randomized, double-blind, placebo-controlled, parallel-group trial. Participants ingested a test beverage containing 5 g RMD or a placebo beverage without RMD. Interviews, anthropometric measurements, physiological examination, blood tests, and urinalyses were conducted at baseline and every 4 wk during the trial. Computed tomography scans were performed at baseline and at the end of week 8 and 12. Results showed that abdominal visceral fat area (VFA) significantly decreased in the test group from 105.33±26.83 cm² at baseline to 101.15±24.33 cm² at week 12. Further, a significant difference was observed in the VFA between the test and control groups (p<0.05), confirming the function of continuous RMD consumption in reducing abdominal visceral fat. Furthermore, neither serious adverse events nor adverse clinical findings were observed in the blood or urine tests following consumption of RMD, suggesting that continuous consumption of RMD containing beverages is safe.

Dietary Fibre Consensus from the International Carbohydrate Quality Consortium (ICQC)

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. A distinction needs to be made between intrinsic sources of dietary fibre and purified forms of fibre, given that the three-dimensional matrix of the plant cell wall confers benefits beyond fibre isolates. Movement through the digestive tract modifies the cell wall structure and may affect the interactions with the colonic microbes (e.g., small intestinally non-absorbed carbohydrates are broken down by bacteria to short-chain fatty acids, absorbed by colonocytes). These aspects, combined with the fibre associated components (e.g., micronutrients, polyphenols, phytosterols, and phytoestrogens), may contribute to the health outcomes seen with the consumption of dietary fibre. Therefore, where possible, processing should minimise the degradation of the plant cell wall structures to preserve some of its benefits. Food labelling should include dietary fibre values and distinguish between intrinsic and added fibre. Labelling may also help achieve the recommended intake of 14 g/1000 kcal/day.

Attenuation of glycaemic and insulin responses following tapioca resistant maltodextrin consumption in healthy subjects: a randomised cross-over controlled trial

Resistant maltodextrin (RMD) from various sources of starch has been extensively studied. However, studies which reported the effects of tapioca RMD (TRM) on glucose and insulin response are lacking. This study investigated the effect of TRM on postprandial plasma glucose and serum insulin in healthy subjects. Additionally, satiety and gastrointestinal tolerability were also evaluated. Sixteen healthy participants received five different treatments on five separate days. Participants received 50 g of either: glucose (GL), tapioca maltodextrin (TM), TRM, MIX15% (7⋅5 g TRM + 42⋅5 g TM) or MIX50% (25 g TRM + 25 g TM). Plasma glucose, serum insulin and subjective appetite responses were measured postprandially over 180 min. Gastrointestinal symptoms were evaluated by questionnaire before and after each test day. Results showed that at 30 min after treatment drinks, plasma glucose after TRM was significantly lowest (104⋅60 (sem 2⋅63 mg/dl) than after GL (135⋅87 (sem 4⋅88) mg/dl; P <0⋅001), TM (127⋅93 (sem 4⋅05) mg/dl; P = 0⋅001), MIX15% (124⋅67 (sem 5⋅73) mg/dl; P = 0⋅039) and MIX50% (129⋅33 (sem 5⋅23) mg/dl; P = 0⋅003) (1 mg/dl = 0⋅0555 mmol/l). In addition, TRM also significantly reduced serum insulin (13⋅01 (sem 2⋅12) μIU/ml) compared with GL (47⋅90 (sem 11⋅93) μIU/ml; P = 0⋅013), TM (52⋅96 (sem 17⋅68) μIU/ml; P = 0⋅002) and MIX50% (33⋅16 (sem 4⋅99) μIU/ml; P = 0⋅008). However, there were no significant differences in subjective appetite between treatments (P > 0⋅05). A single high dose of TRM (50 g) caused flatulence (P < 0⋅05). Tapioca resistant maltodextrin has low digestibility in the small intestine and, therefore, reduced incremental plasma glucose and serum insulin, without affecting satiety in healthy subjects over 180 min. Gastrointestinal tolerability of TRM should be considered when consumed in high doses.

Evidence Supporting a Phased Immuno-physiological Approach to COVID-19 From Prevention Through Recovery

This paper presents an evidence-based strategy for improving clinical outcomes in COVID-19. Recommendations are based on the phases of the disease, because optimal interventions for one phase may not be appropriate for a different phase. The four phases addressed are: Prevention, Infection, Inflammation and Recovery. Underlying this phased approach is recognition of emerging evidence for two different components of pathophysiology, early infection and late stage severe complications. These two aspects of the disease suggest two different patterns of clinical emphasis that seem on the surface to be not entirely concordant. We describe the application of therapeutic strategies and appropriate tactics that address four main stages of disease progression for COVID-19. Emerging evidence in COVID-19 suggests that the SARS-CoV-2 virus may both evade the innate immune response and kill macrophages. Delayed innate immune response and a depleted population of macrophages can theoretically result in a blunted antigen presentation, delaying and diminishing activation of the adaptive immune response. Thus, one clinical strategy involves supporting patient innate and adaptive immune responses early in the time course of illness, with the goal of improving the timeliness, readiness, and robustness of both the innate and adaptive immune responses. At the other end of the disease pathology spectrum, risk of fatality in COVID-19 is driven by excessive and persistent upregulation of inflammatory mechanisms associated with cytokine storm. Thus, the second clinical strategy is to prevent or mitigate excessive inflammatory response to prevent the cytokine storm associated with high mortality risk. Clinical support for immune system pathogen clearance mechanisms involves obligate activation of immune response components that are inherently inflammatory. This puts the goals of the first clinical strategy (immune activation) potentially at odds with the goals of the second strategy(mitigation of proinflammatory effects). This creates a need for discernment about the time course of the illness and with that, understanding of which components of an overall strategy to apply at each phase of the time course of the illness. We review evidence from early observational studies and the existing literature on both outcomes and mechanisms of disease, to inform a phased approach to support the patient at risk for infection, with infection, with escalating inflammation during infection, and at risk of negative sequelae as they move into recovery.

Review: Effects of fibre, grain starch digestion rate and the ileal brake on voluntary feed intake in pigs

Grains rich in starch constitute the primary source of energy for both pigs and humans, but there is incomplete understanding of physiological mechanisms that determine the extent of digestion of grain starch in monogastric animals including pigs and humans. Slow digestion of starch to produce glucose in the small intestine (SI) leads to undigested starch escaping to the large intestine where it is fermented to produce short-chain fatty acids. Glucose generated from starch provides more energy than short-chain fatty acids for normal metabolism and growth in monogastrics. While incomplete digestion of starch leads to underutilised feed in pigs and economic losses, it is desirable in human nutrition to maintain consistent body weight in adults. Undigested nutrients reaching the ileum may trigger the ileal brake, and fermentation of undigested nutrients or fibre in the large intestine triggers the colonic brake. These intestinal brakes reduce the passage rate in an attempt to maximise nutrient utilisation, and lead to increased satiety that may reduce feed intake. The three physiological mechanisms that control grain digestion and feed intake are: (1) gastric emptying rate; (2) interplay of grain digestion and passage rate in the SI controlling the activation of the ileal brake; and (3) fermentation of undigested nutrients or fibre in the large intestine activating the colonic brake. Fibre plays an important role in influencing these mechanisms and the extent of their effects. In this review, an account of the physiological mechanisms controlling the passage rate, feed intake and enzymatic digestion of grains is presented: (1) to evaluate the merits of recently developed methods of grain/starch digestion for application purposes; and (2) to identify opportunities for future research to advance our understanding of how the combination of controlled grain digestion and fibre content can be manipulated to physiologically influence satiety and food intake.

Free sugars

It is clear that the sugars component of the diet has potentially deleterious effects on health. In the past, the dietary sugars were collectively referred to as non-milk extrinsic sugars (UK) or added sugars. The WHO first proposed a new term, free sugars, which is rather broader than added sugars, and also includes the sugars in fruit juices and purees, as well as honey and syrups. This review considers the potential problems that free sugars represent in relation to health risks, and the recent proposals that free sugars are a more appropriate focus than added or total as far as public health initiatives are concerned. This will require major activities in relation to measurement, labelling and communication to the consumer if attempts to reduce dietary free sugars content are to be successful.

Suppressive effect of dietary resistant maltodextrin on systemic immunity in a mouse model of food allergy

Resistant maltodextrin (RMD) is a soluble dietary fibre that exerts several physiological functions as a result of its microbial degradation and changes in the intestinal environment. It has been reported that RMD enhanced immunoglobulin A (IgA) secretion, which protects the mucosa from foreign substances. However, the effect of RMD on excessive immunity has yet to be investigated. In this study, we aimed to investigate the effect of RMD on excessive immune responses such as food allergy. OVA23-3 mice were fed an AIN-76-based diet containing 20% egg-white protein with or without RMD. While RMD was shown to contribute to an increase in goblet cells, RMD did not change the overall inflammatory status when ingested with the egg-white diet. RMD suppressed IL-4 and IL-10 production from splenocytes but not cells from mesenteric lymph nodes. RMD also downregulated the serum levels of OVA-specific Th1- and Th2-related antibodies, which were elevated in the food-allergic condition. RMD significantly increased the total amount of short-chain fatty acids, especially acetate and propionate, in the caecum of OVA23-3 mice fed the egg-white diet. Our study demonstrated that dietary RMD modulates systemic rather than intestinal antigen-specific immune responses in the food-allergic condition of OVA23-3 mice. Although the relevant mechanism has yet to be investigated, RMD shows potential for alleviating food allergy through adjustment of systemic immunity.

High fructose consumption with a high-protein meal is associated with decreased glycemia and increased thermogenesis but reduced fat oxidation: A randomized controlled trial

OBJECTIVES

Fructose is often recommended due to its ability to lower glycemic response and its increased thermogenic effect. Additionally, proteins can reduce the glycemic response of carbohydrate-rich foods and have a high diet-induced thermogenesis (DIT). The aim of this study was to investigate whether the inclusion of fructose in a high-protein meal would demonstrate metabolic advantages.

METHODS

Nineteen Asian women (body mass index 17-28 kg/m²) consumed a low-glycemic index (GI; fructose) or high GI (glucose), high-protein breakfast followed by a standardized lunch in a randomized crossover design. Simultaneously, 8-h continuous glucose monitoring provided incremental area under the curve (iAUC) and 4-h indirect calorimetry provided DIT and respiratory quotient (RQ).

RESULTS

The low GI diet resulted in a lower glucose iAUC (135 ± 25 versus 212 ± 23 mmol/L, P < 0.05) following breakfast, but no second-meal effect after the standardized lunch (217 ± 37 versus 228 ± 27 mmol/L, P < 0.05) compared with the high GI diet. Furthermore, 4-h DIT was greater (40.6 ± 2.3 versus 34.9 ± 1.8 kcal, P < 0.05) and RQ was increased after the fructose high-protein breakfast (0.047 ± 0.009 versus 0.028 ± 0.009, P < 0.05) compared with the glucose meal.

CONCLUSIONS

Fructose is an effective sweetener in reducing glycemia and increasing DIT in the presence of a high-protein diet. However, the reduced fat oxidation after high fructose consumption might present a risk for increased lipogenesis.

Resistant Maltodextrin and Metabolic Syndrome: A Review

Resistant maltodextrin is a non-viscous dietary fiber that is fermentable in the colon by colonic bacteria. The objective of this review is to summarize the studies of resistant maltodextrin and its effect on metabolic profile, such as blood glucose, lipid profile, and body weight. Several studies support the idea that resistant maltodextrin may improve blood glucose, insulin sensitivity, lipid profile, and obesity. However, the use of resistant maltodextrin should be limited to minimize the adverse effect on the gastrointestinal system. This review provides information regarding the benefits of resistant maltodextrin on metabolic health as well as its proposed mechanism to enhance the knowledge of this novel fiber. Key teaching points Resistant maltodextrin is a novel non-viscous dietary fiber classified as resistant starch type V that is produced by debranching of the starch structure. Resistant maltodextrin is fermentable in the colon and thus produces short-chain fatty acid. Resistant maltodextrin helps to maintain blood and lipid profiles as well as promote satiety and reducing food intake. High intake of resistant maltodextrin may cause gastrointestinal discomfort due to the gas production and increased osmotic pressure.

Plant versus animal based diets and insulin resistance, prediabetes and type 2 diabetes: the Rotterdam Study

Vegan or vegetarian diets have been suggested to reduce type 2 diabetes (T2D) risk. However, not much is known on whether variation in the degree of having a plant-based versus animal-based diet may be beneficial for prevention of T2D. We aimed to investigate whether level of adherence to a diet high in plant-based foods and low in animal-based foods is associated with insulin resistance, prediabetes, and T2D. Our analysis included 6798 participants (62.7 ± 7.8 years) from the Rotterdam Study (RS), a prospective population-based cohort in the Netherlands. Dietary intake data were collected with food-frequency questionnaires at baseline of three sub-cohorts of RS (RS-I-1: 1989–1993, RS-II-1: 2000–2001, RS-III-1: 2006–2008). We constructed a continuous plant-based dietary index (range 0–92) assessing adherence to a plant-based versus animal-based diet. Insulin resistance at baseline and follow-up was assessed using homeostasis model assessment of insulin resistance (HOMA-IR). Prediabetes and T2D were collected from general practitioners’ records, pharmacies’ databases, and follow-up examinations in our research center until 2012. We used multivariable linear mixed models to examine association of the index with longitudinal HOMA-IR, and multivariable Cox proportional-hazards regression models to examine associations of the index with risk of prediabetes and T2D. During median 5.7, and 7.3 years of follow-up, we documented 928 prediabetes cases and 642 T2D cases. After adjusting for sociodemographic and lifestyle factors, a higher score on the plant-based dietary index was associated with lower insulin resistance (per 10 units higher score: β = −0.09; 95% CI: − 0.10; − 0.08), lower prediabetes risk (HR = 0.89; 95% CI: 0.81; 0.98), and lower T2D risk [HR = 0.82 (0.73; 0.92)]. After additional adjustment for BMI, associations attenuated and remained statistically significant for longitudinal insulin resistance [β = −0.05 (− 0.06; − 0.04)] and T2D risk [HR = 0.87 (0.79; 0.99)], but no longer for prediabetes risk [HR = 0.93 (0.85; 1.03)]. In conclusion, a more plant-based and less animal-based diet may lower risk of insulin resistance, prediabetes and T2D. These findings strengthen recent dietary recommendations to adopt a more plant-based diet.

Clinical Trial Registry number and website NTR6831, http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=6831.

Insulin Sensitivity and Glucose Homeostasis Can Be Influenced by Metabolic Acid Load

Recent epidemiological findings suggest that high levels of dietary acid load can affect insulin sensitivity and glucose metabolism. Consumption of high protein diets results in the over-production of metabolic acids which has been associated with the development of chronic metabolic disturbances. Mild metabolic acidosis has been shown to impair peripheral insulin action and several epidemiological findings suggest that metabolic acid load markers are associated with insulin resistance and impaired glycemic control through an interference intracellular insulin signaling pathways and translocation. In addition, higher incidence of diabetes, insulin resistance, or impaired glucose control have been found in subjects with elevated metabolic acid load markers. Hence, lowering dietary acid load may be relevant for improving glucose homeostasis and prevention of type 2 diabetes development on a long-term basis. However, limitations related to patient acid load estimation, nutritional determinants, and metabolic status considerably flaws available findings, and the lack of solid data on the background physiopathology contributes to the questionability of results. Furthermore, evidence from interventional studies is very limited and the trials carried out report no beneficial results following alkali supplementation. Available literature suggests that poor acid load control may contribute to impaired insulin sensitivity and glucose homeostasis, but it is not sufficiently supportive to fully elucidate the issue and additional well-designed studies are clearly needed.

Dietary Fiber Intake and Type 2 Diabetes Mellitus: An Umbrella Review of Meta-analyses

Objective

The purpose of this study was to review previously published meta-analyses on the effectiveness of dietary fiber on type 2 diabetes.

Methods

An umbrella review of all published meta-analyses was performed. A PubMed search from January 1, 1980, to April 30, 2017, was conducted using the following search strategy: (fiber OR glucan OR psyllium) AND (meta-analysis OR systematic review). Only English-language publications that provided quantitative statistical analysis on type 2 diabetes, fasting blood glucose concentrations, or glycosylated hemoglobin were retrieved.

Results

Sixteen meta-analyses were retrieved for inclusion in this umbrella review. In the meta-analyses comparing highest versus lowest dietary fiber intake, there was a statistically significant reduction in the relative risk (RR) of type 2 diabetes (RR = 0.81-0.85), with the greatest benefit coming from cereal fibers (RR = 0.67-0.87). However, statistically significant heterogeneity was observed in all of these meta-analyses. In the meta-analyses of supplementation studies using β-glucan or psyllium fibers on type 2 diabetic participants, statistically significant reductions were identified in both fasting blood glucose concentrations and glycosylated hemoglobin percentages.

Conclusion

This review suggests that those consuming the highest amounts of dietary fiber, especially cereal fiber, may benefit from a reduction in the incidence of developing type 2 diabetes. There also appears to be a small reduction in fasting blood glucose concentration, as well as a small reduction in glycosylated hemoglobin percentage for individuals with type 2 diabetes who add β-glucan or psyllium to their daily dietary intake.

The Metabolic Flexibility of Hovering Vertebrate Nectarivores

Foraging hummingbirds and nectar bats oxidize both glucose and fructose from nectar at exceptionally high rates. Rapid sugar flux is made possible by adaptations to digestive, cardiovascular, and metabolic physiology affecting shared and distinct pathways for the processing of each sugar. Still, how these animals partition and regulate the metabolism of each sugar and whether this occurs differently between hummingbirds and bats remain unclear.

Lacto-Vegetarian Diet and Correlation of Fasting Blood Sugar with Lipids in Population Practicing Sedentary Lifestyle

Rising burden of diabetes in India requires quick intervention that integrates policies and programs for effective prevention and control of disease. This retrospective cross-sectional study was conducted to observe effect of diet in two Indian communities practicing sedentary lifestyle. Fasting blood samples were analyzed for blood sugar, glycated-hemoglobin (HbA1C), and lipid profile. Body mass index (BMI) and waist circumference (WC) measurements were recorded. Diabetes incidence was lower in lacto-vegetarian (1.7%) than in non-vegetarian group (5.3%) despite similar lipid profiles and BMI/WC between the groups. Fasting blood sugar (FBS) was positively correlated with LDL and VLDL levels and negatively correlated with HDL, only in lacto-vegetarian group. Study suggests: (1) Indian lacto-vegetarian diet has beneficial effects on diabetes incidence irrespective of high body weight and sedentary lifestyle; (2) intervention to reduce body lipids, such as lipid-lowering drugs and exercise, may have greater effect in reducing FBS levels in this lacto-vegetarian group.

Some Nutritional Characteristics of Enzymatically Resistant Maltodextrin from Cassava (Manihot esculenta Crantz) Starch

Cassava (Manihot esculenta Crantz) native starch was treated with pyroconversion and enzymatic hydrolysis to produce a pyrodextrin and an enzyme-resistant maltodextrin. Some nutritional characteristics were quantified for both compounds. Pyroconversion was done using a 160:1 (p/v) starch:HCl ratio, 90 °C temperature and 3 h reaction time. The resulting pyrodextrin contained 46.21% indigestible starch and 78.86% dietary fiber. Thermostable α-amylase (0.01%) was used to hydrolyze the pyrodextrin at 95 °C for 5 min. The resulting resistant maltodextrin contained 24.45% dextrose equivalents, 56.06% indigestible starch and 86.62% dietary fiber. Compared to the cassava native starch, the pyrodextrin exhibited 56% solubility at room temperature and the resistant maltodextrin 100%. The glycemic index value for the resistant maltodextrin was 59% in healthy persons. Its high indigestible starch and dietary fiber contents, as well as its complete solubility, make the resistant maltodextrin a promising ingredient for raising dietary fiber content in a wide range of foods, especially in drinks, dairy products, creams and soups.

Effects of resistant dextrin for weight loss in overweight adults: a systematic review with a meta-analysis of randomized controlled trials

BACKGROUND

Randomized controlled trials (RCTs) reported that resistant dextrin (RD) exerted pleiotropic effects on humans. However, limited information is available on the effects of RD for weight loss. We conducted a systematic review with a meta-analysis to summarize the available literature and compare the efficacy of RD for weight loss with that of a placebo in overweight adults.

METHODS

We searched the electronic databases MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Web of Science, ClincalTrials.gov, and Japana Centra Revuo Medicina (Ichushi-web) for studies from their onset to November 2016, and there was no language restriction. Trials were included if they were RCTs (1) comparing the effects of RD with a placebo in adults (18 years or older), (2) reporting body mass index, and (3) including overweight/obese subjects as defined by the authors of RCTs. The weighted mean difference with a 95% confidence interval (CI) was calculated using a random-effects model.

RESULTS

Of the 484 studies retrieved, 3 RCTs involving 275 subjects were included in our review. The durations of RCTs ranged between 8 and 12 weeks. All RCTs were conducted in Asian countries. RD significantly improved body mass index [mean difference -0.39 (95% CI -0.57 to -0.21) kg/m², p < 0.01] and body weight [mean difference -0.81 (95% CI -0.93 to -0.69) kg, p < 0.01] in overweight adults.

CONCLUSION

Our review suggests that RD exerts beneficial effects for weight loss in overweight adults. More RCTs with different populations and longer follow-ups are needed in order to confirm that supplementation with RD has beneficial effects for weight loss in overweight adults. We consider this review to provide important information for the future submission of food with health claims.

Effects of Higher Dietary Protein and Fiber Intakes at Breakfast on Postprandial Glucose, Insulin, and 24-h Interstitial Glucose in Overweight Adults

Dietary protein and fiber independently influence insulin-mediated glucose control. However, potential additive effects are not well-known. Men and women (n = 20; age: 26 ± 5 years; body mass index: 26.1 ± 0.2 kg/m²; mean ± standard deviation) consumed normal protein and fiber (NPNF; NP = 12.5 g, NF = 2 g), normal protein and high fiber (NPHF; NP = 12.5 g, HF = 8 g), high protein and normal fiber (HPNF; HP = 25 g, NF = 2 g), or high protein and fiber (HPHF; HP = 25 g, HF = 8 g) breakfast treatments during four 2-week interventions in a randomized crossover fashion. On the last day of each intervention, meal tolerance tests were completed to assess postprandial (every 60 min for 240 min) serum glucose and insulin concentrations. Continuous glucose monitoring was used to measure 24-h interstitial glucose during five days of the second week of each intervention. Repeated-measures ANOVA was applied for data analyses. The HPHF treatment did not affect postprandial glucose and insulin responses or 24-h glucose total area under the curve (AUC). Higher fiber intake reduced 240-min insulin AUC. Doubling the amount of protein from 12.5 g to 25 g/meal and quadrupling fiber from 2 to 8 g/meal at breakfast was not an effective strategy for modulating insulin-mediated glucose responses in these young, overweight adults.

Resistant maltodextrin or fructooligosaccharides promotes GLP-1 production in male rats fed a high-fat and high-sucrose diet, and partially reduces energy intake and adiposity

PURPOSE

Increasing secretion and production of glucagon-like peptide-1 (GLP-1) by continuous ingestion of certain food components has been expected to prevent glucose intolerance and obesity. In this study, we examined whether a physiological dose (5% weight in diet) of digestion-resistant maltodextrin (RMD) has a GLP-1-promoting effect in rats fed a high-fat and high-sucrose (HFS) diet.

METHODS

Rats were fed a control diet or the HFS (30% fat, 40% sucrose wt/wt) diet supplemented with 5% RMD or fructooligosaccharides (FOS) for 8 weeks or for 8 days in separated experiments. Glucose tolerance, energy intake, plasma and tissue GLP-1 concentrations, and cecal short-chain fatty acids concentrations were assessed.

RESULTS

After 4 weeks of feeding, HFS-fed rats had significantly higher glycemic response to oral glucose than control rats, but rats fed HFS + RMD/FOS did not (approx. 50% reduction vs HFS rats). HFS + RMD/FOS-fed rats had higher GLP-1 responses (~twofold) to oral glucose, than control rats. After 8 weeks, visceral adipose tissue weight was significantly higher in HFS-fed rats than control rats, while HFS + RMD/FOS rats had a trend of reduced gain (~50%) of the tissue weight. GLP-1 contents and luminal propionate concentrations in the large intestine increased (>twofold) by adding RMD/FOS to HFS. Eight days feeding of RMD/FOS-supplemented diets reduced energy intake (~10%) and enhanced cecal GLP-1 production (~twofold), compared to HFS diet.

CONCLUSIONS

The physiological dose of a prebiotic fiber promptly (within 8 days) promotes GLP-1 production in rats fed an obesogenic diet, which would help to prevent excess energy intake and fat accumulation.

O uso do carboidrato antes da atividade física como recurso ergogênico: revisão sistemática

A dieta dos atletas requer aporte energético adequado, sendo a principal fonte energética os carboidratos CHO que são encontrados livremente na corrente sanguínea ou armazenados nos músculos e no fígado. Com base na rotina de treinos e competições, ou mesmo na quantidade exacerbada de energia necessária, é comum a necessidade de suplementação de CHO, seja na forma de bebidas, géis, barras ou balas energéticas, antes, durante ou depois da atividade física. Devido à importância dos CHO foram reunidos estudos que testaram a suplementação com diferentes CHO antes do exercício para aumento da performance. Foram investigados artigos e teses cuja publicação ocorreu a partir de 2006 em bases científicas eletrônicas e banco de teses de faculdades renomadas na área. Os CHO podem ser divididos segundo a quantidade de moléculas que o compõem, as quais também são diferenciadas também por digestão, absorção, viscosidade, dulçor, índice glicêmico IG e oxidação durante a atividade. Comparando-se a taxa de oxidação, foram encontrados melhores resultados quando os CHO ingeridos são de alto teor de IG glicose e sacarose e baixo teor de IG frutose ao se realizar atividade de média a alta intensidade de longa duração. A ingestão de CHO antes do exercício mostrou-se eficiente nos nove estudos analisados, sendo que dois deles apresentaram relevância p < 0,005. Mesmo com a ingestão de CHO com diferentes IG, observou-se melhora, não sendo relatada hipoglicemia de rebote como teorizado na literatura. A suplementação de CHO com a composição e administração apropriadas mostrou-se eficiente para aumento do desempenho físico.

Resistant maltodextrin promotes fasting glucagon-like peptide-1 secretion and production together with glucose tolerance in rats

Glucagon-like peptide-1 (GLP-1), which is produced and released from enteroendocrine L cells, plays pivotal roles in postprandial glycaemia. The ingestion of resistant maltodextrin (RMD), a water-soluble non-digestible saccharide, improves the glycaemic response. In the present study, we examined whether the continuous feeding of RMD to rats affected GLP-1 levels and glycaemic control. Male Sprague-Dawley rats (6 weeks of age) were fed an American Institute of Nutrition (AIN)-93G-based diet containing either cellulose (5 %) as a control, RMD (2.5 or 5 %), or fructo-oligosaccharides (FOS, 2.5 or 5 %) for 7 weeks. During the test period, an intraperitoneal glucose tolerance test (IPGTT) was performed after 6 weeks. Fasting GLP-1 levels were significantly higher in the 5 % RMD group than in the control group after 6 weeks. The IPGTT results showed that the glycaemic response was lower in the 5 % RMD group than in the control group. Lower caecal pH, higher caecal tissue and content weights were observed in the RMD and FOS groups. Proglucagon mRNA levels were increased in the caecum and colon of both RMD and FOS groups, whereas caecal GLP-1 content was increased in the 5 % RMD group. In addition, a 1 h RMD exposure induced GLP-1 secretion in an enteroendocrine L-cell model, and single oral administration of RMD increased plasma GLP-1 levels in conscious rats. The present study demonstrates that continuous ingestion of RMD increased GLP-1 secretion and production in normal rats, which could be stimulated by its direct and indirect (enhanced gut fermentation) effects on GLP-1-producing cells, and contribute to improving glucose tolerance.

The metabolizable energy of dietary resistant maltodextrin is variable and alters fecal microbiota composition in adult men

Resistant maltodextrin (RM) is a novel soluble, nonviscous dietary fiber. Its metabolizable energy (ME) and net energy (NE) values derived from nutrient balance studies are unknown, as is the effect of RM on fecal microbiota. A randomized, placebo-controlled, double-blind crossover study was conducted (n = 14 men) to determine the ME and NE of RM and its influence on fecal excretion of macronutrients and microbiota. Participants were assigned to a sequence consisting of 3 treatment periods [24 d each: 0 g/d RM + 50 g/d maltodextrin and 2 amounts of dietary RM (25 g/d RM + 25 g of maltodextrin/d and 50 g/d RM + 0 g/d maltodextrin)] and were provided all the foods they were to consume to maintain their body weight. After an adaptation period, excreta were collected during a 7-d period. After the collection period, 24-h energy expenditure was measured. Fluorescence in situ hybridization, quantitative polymerase chain reaction, and 454 titanium technology-based 16S rRNA sequencing were used to analyze fecal microbiota composition. Fecal amounts of energy (544, 662, 737 kJ/d), nitrogen (1.5, 1.8, 2.1 g/d), RM (0.3, 0.6, 1.2 g/d), and total carbohydrate (11.1, 14.2, 16.2 g/d) increased with increasing dose (0, 25, 50 g) of RM (P < 0.0001). Fat excretion did not differ among treatments. The ME value of RM was 8.2 and 10.4 kJ/g, and the NE value of RM was -8.2 and 2.0 kJ/g for the 25 and 50 g/d RM doses, respectively. Both doses of RM increased fecal wet weight (118, 148, 161 g/d; P < 0.0001) and fecal dry weight (26.5, 32.0, 35.8 g/d; P < 0.0001) compared with the maltodextrin placebo. Total counts of fecal bacteria increased by 12% for the 25 g/d RM dose (P = 0.17) and 18% for the 50 g/d RM dose (P = 0.019). RM intake was associated with statistically significant increases (P < 0.001) in various operational taxonomic units matching closest to ruminococcus, eubacterium, lachnospiraceae, bacteroides, holdemania, and faecalibacterium, implicating RM in their growth in the gut. Our findings provide empirical data important for food labeling regulations related to the energy value of RM and suggest that RM increases fecal bulk by enhancing the excretion of nitrogen and carbohydrate and the growth of specific microbial populations.

The effect of dietary fibre on reducing the glycaemic index of bread

As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies have been carried out in order to decrease the GI of bread. The most relevant strategy that has been applied so far is the addition of fibre-rich flours or pure dietary fibre. However, the effectiveness of dietary fibre in bread in reducing the GI is controversial. The purpose of the present review was to discuss critically the effects obtained by adding different kinds of fibre to bread in order to modulate its glycaemic response. The studies were selected because they analysed in vivo whether or not dietary fibre, naturally present or added during bread making, could improve the glucose response. The reviewed literature suggests that the presence of intact structures not accessible to human amylases, as well as a reduced pH that may delay gastric emptying or create a barrier to starch digestion, seems to be more effective than dietary fibre per se in improving glucose metabolism, irrespective of the type of cereal. Moreover, the incorporation of technologically extracted cereal fibre fractions, the addition of fractions from legumes or of specifically developed viscous or non-viscous fibres also constitute effective strategies. However, when fibres or wholemeal is included in bread making to affect the glycaemic response, the manufacturing protocol needs to reconsider several technological parameters in order to obtain high-quality and consumer-acceptable breads.

Heterogeneous effects of fructose on blood lipids in individuals with type 2 diabetes: systematic review and meta-analysis of experimental trials in humans

OBJECTIVE

Because of blood lipid concerns, diabetes associations discourage fructose at high intakes. To quantify the effect of fructose on blood lipids in diabetes, we conducted a systematic review and meta-analysis of experimental clinical trials investigating the effect of isocaloric fructose exchange for carbohydrate on triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol in type 1 and 2 diabetes.

RESEARCH DESIGN AND METHODS

We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Library for relevant trials of > or =7 days. Data were pooled by the generic inverse variance method and expressed as standardized mean differences with 95% CI. Heterogeneity was assessed by chi(2) tests and quantified by I(2). Meta-regression models identified dose threshold and independent predictors of effects.

RESULTS

Sixteen trials (236 subjects) met the eligibility criteria. Isocaloric fructose exchange for carbohydrate raised triglycerides and lowered total cholesterol under specific conditions without affecting LDL cholesterol or HDL cholesterol. A triglyceride-raising effect without heterogeneity was seen only in type 2 diabetes when the reference carbohydrate was starch (mean difference 0.24 [95% CI 0.05-0.44]), dose was >60 g/day (0.18 [0.00-0.37]), or follow-up was < or =4 weeks (0.18 [0.00-0.35]). Piecewise meta-regression confirmed a dose threshold of 60 g/day (R(2) = 0.13)/10% energy (R(2) = 0.36). A total cholesterol-lowering effect without heterogeneity was seen only in type 2 diabetes under the following conditions: no randomization and poor study quality (-0.19 [-0.34 to -0.05]), dietary fat >30% energy (-0.33 [-0.52 to -0.15]), or crystalline fructose (-0.28 [-0.47 to -0.09]). Multivariate meta-regression analyses were largely in agreement.

CONCLUSIONS

Pooled analyses demonstrated conditional triglyceride-raising and total cholesterol-lowering effects of isocaloric fructose exchange for carbohydrate in type 2 diabetes. Recommendations and large-scale future trials need to address the heterogeneity in the data.