Sustained pectin ingestion: effect on gastric emptying and glucose tolerance in non-insulin-dependent diabetic patients

Functional Characterization and Toxicity of Pectin from Red Chilto Fruit Waste (Peels)

BACKGROUND

Food and agricultural wastes constitute a rich source of functional ingredients for the food, pharmaceutical, and cosmetic industries. In this context, by-products from the red variety of Solanum betaceum fruits (chilto) from Northwestern Argentina are suitable sources for pectin extraction.

METHODS

In this study, pectin from the peels of red chilto fruits was extracted and characterized.

RESULTS

The recovery yield of red chilto peel pectin was about 24%, and it was co-extracted with 40.0 mg phenolic compounds, 6.5 mg anthocyanins, and 4.7 g proteins per 100 g of pectin. The pectin obtained from red chilto showed proper technological functionality displaying water and oil holding capacities of 4.2 and 2.0%, respectively, an emulsifying capacity of 83%, emulsion stability of 87.5%, foaming capacity of 21.1%, and foaming stability of 79.1%. The pectin displayed antioxidant activity with the ability to scavenge ABTS radical, superoxide anion, and H₂O₂. The polysaccharide exhibited in vitro hypoglycemic potential and inhibited the α-amylase enzyme, retarded glucose diffusion, and improved the cellular uptake of glucose in a Saccharomyces cerevisiae model. The extract was non-toxic on acute toxicity tests.

CONCLUSIONS

Red chilto pectin showed potential as a new and safe functional ingredient for the design of foods, health products, and cosmetics.

Computational formulation study of insulin on biodegradable polymers

Insulin administered orally has a limited therapeutic profile due to factors such as digestion enzymes, pH, temperature, and acidic conditions in the gastrointestinal tract. Type 1 diabetes patients are typically restricted to use intradermal insulin injections to manage their blood sugar levels as oral administration is not available. Research has shown that polymers could enhance the oral bioavailability of therapeutic biologicals, but traditional methods for developing suitable polymers are time-consuming and resource-intensive. Although computational formulations can be used to identify the best polymers more quickly. The true potential of biological formulations has not been fully explored due to a lack of benchmarking studies. Therefore, molecular modelling techniques were used as a case study in this research to determine which polymer is most compatible among five natural biodegradable polymers to address insulin stability. Specially, molecular dynamics simulations were conducted in order to compare insulin-polymer mixtures at different pH levels and temperatures. Hormonal peptide morphological properties were analyzed in body and storage conditions to assess stability of insulin with and without polymers. According to our computational simulations and energetic analyses, polymer cyclodextrin and chitosan maintain insulin stability the most effectively, while alginate and pectin are less effective relatively. Overall, this study contributes valuable insight into the role of biopolymers in stabilizing hormonal peptides in biological and storage conditions. A study such as this could have a significant impact on the development of new drug delivery systems and encourage scientists to utilize them in the formulation of biologicals.

Application of prebiotics in apple products and potential health benefits

Among the fruits, the apple stands out among the most used for elaboration of processed foods. However, the importance of prebiotics in apple products has never been widely analyzed. Prebiotic is a food component resistant to gastric acidity, digestion by mammalian enzymes and gastrointestinal absorption. But following fermentation in the colon, prebiotics result in specific changes in the composition and / or metabolism of the gastrointestinal microbiota, conferring benefits to the health of the host. Therefore, fortifying apple-based products with additional prebiotics is an important strategy for improving consumer health benefits. In this review, after compiling and analyzing scientific and technological studies focusing on prebiotics in apple products, the following benefits of these prebiotics became evident: (1) reduction of water loss in the food matrix; (2) preservation of bioactive and volatile compounds; (3) texture improvement (thickening) in the food industry; (4) increased shelf-live and (5) increased survival of probiotic bacteria, promoting positive effects on microbiota. In addition, this review shows the benefits of different prebiotics for stability and sensory acceptance of apple processed foods.

Valorisation of Fruit & Vegetable Wastes: A Review

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Fruits and vegetables play an important part in the diets of global human population. During processing, the unused residues, such as peels, stalks, rinds, stem, leaves etc., come out as waste. Due to the high moisture content of these perishable wastes, they undergo rapid decomposition that leads to foul odour and growth of pathogens. Almost 30% of the loss occurs at the supply, retail, consumer, post-harvest and processing level. The perishable waste like peels, pomace, seeds etc., act as threat to the environment and degrade pollution-free model. The wastes are rich in protein, carbohydrates, minerals, vitamins and other phytochemicals and bioactive compounds, such as pigments, dietary fibre, essential oils, etc. Recent researches have shown that there is an increase in the utilization of these wastes for the extraction of value- added products, such as bioactive compounds, bio-colorants, organic acids, single cell protein (SCP), organic minerals, enzymes and others. The present review paper deals with the recent studies conducted on the valorisation of the fruit & vegetable waste.

Therapeutic Potential of Various Plant-Based Fibers to Improve Energy Homeostasis via the Gut Microbiota

Obesity is due in part to increased consumption of a Western diet that is low in dietary fiber. Conversely, an increase in fiber supplementation to a diet can have various beneficial effects on metabolic homeostasis including weight loss and reduced adiposity. Fibers are extremely diverse in source and composition, such as high-amylose maize, β-glucan, wheat fiber, pectin, inulin-type fructans, and soluble corn fiber. Despite the heterogeneity of dietary fiber, most have been shown to play a role in alleviating obesity-related health issues, mainly by targeting and utilizing the properties of the gut microbiome. Reductions in body weight, adiposity, food intake, and markers of inflammation have all been reported with the consumption of various fibers, making them a promising treatment option for the obesity epidemic. This review will highlight the current findings on different plant-based fibers as a therapeutic dietary supplement to improve energy homeostasis via mechanisms of gut microbiota.

Continuous and pulsed ultrasound pectin extraction from navel orange peels

Pectin is a valuable product (up to 30 $kg^-1) that makes-up 20-30% of an orange's peel. The commercial extraction is lengthy (up to 6h) and energy intensive as it requires heating aqueous solutions (60-100 °C). Ultrasound speeds up the extraction process reducing processing time by macroscopic and microscopic mixing by acoustic cavitation. We adopted an ultrasonic horn to deliver a rated power of 500W at amplitudes of 20%, 40%, and 60% with and without pulsation to extract pectin from waste orange peels. These correspond to power densities of 0.08Wml^-1, 0.16Wml^-1 and 0.24Wml^-1, respectively. The extractions operated at a pH of either 2 or 3. The experimental data agree with the fitted values from the statistical model (R²=95.5%). The model confirms our predictions that yield increases with amplitude/power density and decreasing pH. The highest yield was (11%) at a pH of 2 and with continuous ultrasonic irradiation at a power density of 0.24Wml^-1. There is only a 1.3% difference between this datum and pulse ultrasound mode (1 s on/1 s off) at the same conditions - a Student's t test confirmed that there was no significant difference in yield between continuous and pulse mode. However, pulsing is more efficient in that it consumes less than half the energy of continuous operation (80kJ vs. 190kJ).

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Prebiotics metabolism by gut-isolated probiotics

There are numerous species of bacteria resides in the lumen of human colon. The word 'colon', resembles colony or the colonization of microbiota of which plays an important role in the fermentation of prebiotics. The standpoint of prebiotic nowadays is well reported for attenuating gut dysbiosis in many clinical studies tested on animals and human. However, because of the huge amount of gut microbiome, the attempt to connect the dots between bacterial population and the host are not plainly discernible. Thus, a need to analyse recent research on the pathways of prebiotic metabolism adopted by commonly studied probiotics i.e. Bifidobacteria and Lactobacillus. Several different substrate-dependent gene expressions are induced to break down oligosaccharide molecules shown by those probiotics. The hydrolysis can occur either by membrane bound (extracellular) or cytoplasmic (intracellular) enzyme of the enteric bacteria. Therefore, this review narrates several prebiotic metabolisms occur during gut fermentation, and metabolite production i.e. organic acids conversion.

Potential of Pectins to Beneficially Modulate the Gut Microbiota Depends on Their Structural Properties

Pectins are plant cell-wall polysaccharides which can be utilized by commensal bacteria in the gut, exhibiting beneficial properties for the host. Knowledge of the impact of pectins on intestinal bacterial communities is insufficient and limited to a few types of pectins. This study characterized the relationship between the structural properties of pectins and their potential to modulate composition and activity of the gut microbiota in a beneficial way. For this purpose we performed in vitro fermentations of nine structurally diverse pectins from citrus fruits and sugar beet, and a pectic derivative, rhamnogalacturonan I (RGI), using a TIM-2 colon model. The composition of microbiota during TIM-2 fermentations was assessed by 16S rRNA gene amplicon sequencing. Both general and pectin-specific changes were observed in relative abundances of numerous bacterial taxa in a time-dependent way. Bacterial populations associated with human health, such as Faecalibacterium prausnitzii, Coprococcus, Ruminococcus, Dorea, Blautia, Oscillospira, Sutterella, Bifidobacterium, Christensenellaceae, Prevotella copri, and Bacteroides spp. were either increased or decreased depending on the substrate, suggesting that these bacteria can be controlled using structurally different pectins. The main structural features linked to the pectin-mediated shifts in microbiota included degree of esterification, composition of neutral sugars, distribution of homogalacturonan and rhamnogalacturonan fractions, degree of branching, and the presence of amide groups. Cumulative production of the total short chain fatty acids and propionate was largest in fermentations of the high methoxyl pectins. Thus, this study indicates that microbial communities in the gut can be specifically modulated by pectins and identifies the features in pectin molecules linked to microbial alterations. This knowledge can be used to define preferred dietary pectins, targeting beneficial bacteria, and favoring more balanced microbiota communities in the gut.

The Role of Fiber in Energy Balance

Excessive energy intake is linked with obesity and subsequent diet-related health problems, and it is therefore a major nutritional challenge. Compared with the digestible carbohydrates starch and sugars, fiber has a low energy density and may have an attenuating effect on appetite. This narrative review attempts to clarify the net energy contributions of various fibers, and the effect of fiber on satiety and thus appetite regulation. Fibers, broadly defined as nonstarch polysaccharides, are a varied class of substances with vastly different physicochemical properties depending on their chemical arrangement. Thus, net energy content can vary from more than 10 kJ/g for soluble, nonviscous, and easily fermentable fibers such as those in many fruits, to less than zero for viscous fibers with anti-nutritive properties, such as certain types of fibers found in rye and other cereals. Likewise, some fibers will increase satiety by being viscous or contribute to large and/or swollen particles, which may facilitate mastication and increase retention time in the stomach, or potentially through fermentation and an ensuing satiety-inducing endocrine feedback from the colon. Thus, fibers may clearly contribute to energy balance. The metabolizable energy content is very often considerably lower than the commonly used level of 8 kJ per g fiber, and some fibers may reduce energy intake indirectly through satiety-inducing effects. A more precise characterization of fiber and its physicochemical effects are required before these beneficial effects can be fully exploited in human nutrition.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

Pectin Esterification Degree in the Bioavailability of Non-heme Iron in Women

Pectins are a type of soluble fiber present in natural and processed foods. Evidence regarding the effect of esterification degree of pectins on iron absorption in humans is scarce. In the present study, the effect of pectins with different degrees of esterification on non-heme iron absorption in women was evaluated. A controlled experimental study was conducted with block design, involving 13 apparently healthy, adult women. Each subject received 5 mg Fe (FeSO₄) without pectin (control) or accompanied by 5 g citrus pectin, two with a low degree of esterification (27 and 36%), and one with a high degree of esterification (67 to 73%), each on different days. Each day, the 5 mg Fe doses were marked with radioactive ⁵⁹Fe or ⁵⁵Fe. Radioactivity incorporated into erythrocytes was determined in blood samples 14 days after the marked Fe doses were consumed. On days 18 and 36 of study, 30 and 20 mL blood samples were obtained, respectively, and blood sample radioactivity incorporated into erythrocytes was determined. Body iron status was determined from blood taken on day 18. Whole body blood volume was estimated for calculate iron bioavailability; it was assumed that 80% of absorbed radioactivity was incorporated into the Hb. All women participants signed an informed consent of participation at baseline. Iron bioavailability (mean geometric ±1 SD) alone (control) was 18.2% (12.3-27.1%), iron + pectin27 was 17.2% (10.2-29.2%), iron + pectin36 was 15.3% (9.5-24.6%), and iron + pectin67 was 19.5% (10.0-38.0%). No statistically significant differences between iron bioavailability (repeated measures ANOVA, p = 0.22) were observed. Pectin esterification degree does not influence the bioavailability of non-heme iron in women.

Investigation of mechanisms involved in postprandial glycemia and insulinemia attenuation with dietary fibre consumption

This work examines the mechanisms involved in the attenuation of postprandial glycemic and insulinemic responses associated with soluble dietary fibre (SDF) consumption. The effect of SDF, including yellow mustard mucilage, soluble flaxseed gum and fenugreek gum on in vitro amylolysis and maltose transport was studied. Furthermore, a human clinical trial was conducted to investigate the effect of SDF consumption on postprandial glycemic and insulinemic responses and gastric emptying, as estimated based on the absorption of paracetamol. Participants (n = 15) at risk for type II diabetes consumed maltose syrup- and starch-based pudding treatments supplemented with each SDF, each at a concentration to match three times the apparent viscosity (18.54 mPa s at 60 s^-1) equivalent to the European Food Safety Authority (2011) glycemia control health claim for cereal β-glucan, measured under simulated small intestinal conditions. The presence of each SDF delayed in vitro amylolysis to a similar extent, but had no effect on maltose transport. Generally, all SDF-containing treatments attenuated blood glucose and plasma insulin peak concentrations and plasma paracetamol 1 h incremental area under the curve values to a similar extent, relative to the controls, despite differences in the amounts at which each SDF was used (from 5.9 to 15.5 g). The postprandial attenuations were related to the ability of each SDF to modify digesta viscosity, perhaps through the delay of gastric emptying, as a delay of amylolysis and sugar transport under simulated upper intestinal conditions did not seem to have a substantial effect.

Effect of supplementation with different proportions of barley grain or citrus pulp on the digestive utilization of ammonia-treated straw by sheep

The effect of carbohydrate supplementation on rumen utilization of ammonia-treated straw was studied in four rumen-cannulated ewes (42•0 (s.e. 2•80) kg live weight) in a Latin-square design. Diets were a 50: 50 mixture of ammoniated barley straw and a concentrate made up with different ratios of barley grain and citrus pulp, namely M1 (100: 0), M2 (66: 33), M3 (33: 66) and M4 (0: 100). Concentrates also included soya-bean meal and urea to make diets isonitrogenous. Diets were given in one meal in the morning at 0•8 kg/day. There were no significant differences among treatments in daily weighted means of rumen pH and concentration of volatile fatty acids. Acetate, propionate and butyrate molar proportions were not different among treatments, but proportions of isobutyrate (P < 0•05) and isovalerate (P < 0•10) were higher for M1 and M2. Ammonia concentration immediately before feeding was lower (P < 0•05) for M3 and M4 (72•1 and 51•3 mg/l) than for M1 and M2 (97•0 and 107•9 mg/ l). Total rumen bacterial concentration was higher (P < 0•05) with the highest barley proportion, whereas enzymatic activity against structural carbohydrates of particle-associated bacteria did not differ significantly among treatments. Digestibility of neutral-detergent fibre increased (P < 0•05) with the increase in the proportion of citrus pulp in the concentrate (0•647, 0•674, 0•684 and 0•693 for M1, M2, M3 and M4; s.e. = 0•0086). Urinary excretion of purine derivatives decreased linearly (P < 0•05) as the proportion of citrus pulp in the diet increased, while faecal excretion of purine bases was not significantly affected by dietary treatments.

Weight and Glucose Reduction Observed with a Combination of Nutritional Agents in Rodent Models Does Not Translate to Humans in a Randomized Clinical Trial with Healthy Volunteers and Subjects with Type 2 Diabetes

Background

Nutritional agents have modest efficacy in reducing weight and blood glucose in animal models and humans, but combinations are less well characterized. GSK2890457 (GSK457) is a combination of 4 nutritional agents, discovered by the systematic assessment of 16 potential components using the diet-induced obese mouse model, which was subsequently evaluated in a human study.

Nonclinical Results

In the diet-induced obese mouse model, GSK457 (15% w/w in chow) given with a long-acting glucagon-like peptide -1 receptor agonist, exendin-4 AlbudAb, produced weight loss of 30.8% after 28 days of treatment. In db/db mice, a model of diabetes, GSK457 (10% w/w) combined with the exendin-4 AlbudAb reduced glucose by 217 mg/dL and HbA1c by 1.2% after 14 days.

Clinical Results

GSK457 was evaluated in a 6 week randomized, placebo-controlled study that enrolled healthy subjects and subjects with type 2 diabetes to investigate changes in weight and glucose. In healthy subjects, GSK457 well tolerated when titrated up to 40 g/day, and it reduced systemic exposure of metformin by ~ 30%. In subjects with diabetes taking liraglutide 1.8 mg/day, GSK457 did not reduce weight, but it slightly decreased mean glucose by 0.356 mmol/L (95% CI: -1.409, 0.698) and HbAlc by 0.065% (95% CI: -0.495, 0.365), compared to placebo. In subjects with diabetes taking metformin, weight increased in the GSK457-treated group [adjusted mean % increase from baseline: 1.26% (95% CI: -0.24, 2.75)], and mean glucose and HbA1c were decreased slightly compared to placebo [adjusted mean glucose change from baseline: -1.22 mmol/L (95% CI: -2.45, 0.01); adjusted mean HbA1c change from baseline: -0.219% (95% CI: -0.910, 0.472)].

Conclusions

Our data demonstrate remarkable effects of GSK457 in rodent models of obesity and diabetes, but a marked lack of translation to humans. Caution should be exercised with nutritional agents when predicting human efficacy from rodent models of obesity and diabetes.

Trial Registration

ClinicalTrials.gov NCT01725126

Effect of two dietary fibers on satiety and glycemic parameters: a randomized, double-blind, placebo-controlled, exploratory study

BACKGROUND

Dietary carbohydrates may affect metabolic and physiologic parameters. The present study evaluated whether a combination of two dietary fibers, oligofructose (OFS) and pectin (P), altered satiety and glycemic parameters. The primary objective of this study was to determine whether dietary supplementation for 3 weeks with OFS + P would produce a greater reduction in energy intake of an ad libitum test meal compared to control.

METHODS

This was a single center, randomized, double-blind, placebo-controlled, parallel group study in overweight and obese, otherwise healthy, subjects (N = 96). There were two OFS + P treatment groups: high-dose (30 g/d), low-dose (15 g/d), and a control group (maltodextrin 15 g/d). Energy intake, appetite measures based on Satiety Labeled Intensity Magnitude (SLIM) scale, fasting and post-prandial glucose, and insulin levels and body weight were measured at baseline and at the end of 3 weeks. Adverse events and gastrointestinal tolerability of the treatments were also assessed.

RESULTS

An analysis of covariance (ANCOVA) performed on the primary endpoint change from baseline in energy intake, showed no statistically significant difference in energy intake among the three treatment groups (p = 0.5387). The LS mean changes (SE) in energy intake from baseline to week 3 were -58.3 (42.4) kilocalories (kcal) for the high dose group, -74.2 (43.6) kcal for the low dose group, and -9.0 (42.9) kcal for the control group. For the pairwise comparisons of OFS + P doses and control, confidence intervals were constructed around the difference in LS mean changes. All study products were generally well tolerated.

CONCLUSION

There was a directional benefit in ad libitum energy intake for both OFS + P doses compared to control, with a greater reduction in kilocalories in the low dose comparison, but the reductions were not significant. Further studies are warranted.

CLINICAL TRIAL REGISTRATION

GSK Clinical Study Register # W7781293.

Satiety and energy intake after single and repeated exposure to gel-forming dietary fiber: post-ingestive effects

BACKGROUND

Viscous or gel-forming dietary fibers can increase satiety by a more firm texture and increased eating time. Effects of viscous or gel-forming fibers on satiety by post-ingestive mechanisms such as gastric emptying, hormonal signals, nutrient absorption or fermentation are unclear. Moreover, it is unclear whether the effects persist after repeated exposure.

OBJECTIVE

To investigate satiety and energy intake after single and repeated exposure to gelled fiber by post-ingestive mechanisms.

DESIGN

In a two-arm crossover design, 32 subjects (24 female subjects, 21±2 y, BMI 21.8±1.9 kg m(-2)) consumed test foods once daily for 15 consecutive days, with 2 weeks of washout. Test foods were isocaloric (0.5 MJ, 200 g) with either 10 g gel-forming pectin or 3 g gelatin and 2 g starch, matched for texture and eating time. Hourly satiety ratings, ad libitum energy intake and body weight were measured on days 1 (single exposure) and 15 (repeated exposure). In addition, hourly breath hydrogen, fasting glucose, insulin, leptin and short-chain fatty acids were measured.

RESULTS

Subjects rated hunger, desire to eat and prospective intake about 2% lower (P<0.015) and fullness higher (+1.4%; P=0.041) when they received pectin compared with control. This difference was similar after single and repeated exposure (P>0.64). After receiving pectin, energy intake was lower (-5.6%, P=0.012) and breath hydrogen was elevated (+12.6%, P=0.008) after single exposure, but not after repeated exposure. Fasting glucose concentrations were higher both after single and repeated exposure to pectin (+2.1%, P=0.019). Body weight and concentrations of insulin, leptin and short-chain fatty acids did not change during the study.

CONCLUSIONS

Gelled pectin can increase satiety and reduce energy intake by post-ingestive mechanisms. Although the effects were small, the effects on satiety were consistent over time, whereas the effects on energy intake reduction were not.

Bioavailability of epicatechin and effects on nitric oxide metabolites of an apple flavanol-rich extract supplemented beverage compared to a whole apple puree: a randomized, placebo-controlled, crossover trial

SCOPE

Flavanol-rich foods are known to exert beneficial effects on cardiovascular health. The biological effects depend on bioavailability of flavanols which may be influenced by food matrix and dose ingested. We compared the bioavailability and dose-response of epicatechin from whole apple and an epicatechin-rich extract, and the effects on plasma and urinary nitric oxide (NO) metabolites.

METHODS AND RESULTS

In a randomized, placebo-controlled, crossover trial, subjects consumed drinks containing 70 and 140 mg epicatechin from an apple extract and an apple puree containing 70 mg epicatechin. Blood and urine samples were collected for 24 h post ingestion. Maximum plasma concentration, AUC(0-24 h) , absorption and urinary excretion were all significantly higher after ingestion of both epicatechin drinks compared with apple puree (p < 0.05). Time to maximum plasma concentration was significantly later for the puree compared with the drinks (p < 0.01). Epicatechin bioavailability was >2-fold higher after ingestion of the 140 mg epicatechin drink compared to the 70 mg epicatechin drink (p < 0.05). Excretion of NO metabolites was higher for all test products compared with placebo, which was significant for the high dose drink (p = 0.016).

CONCLUSIONS

Oral bioavailability of apple epicatechin increases at higher doses, is reduced by whole apple matrix and has the potential to increase NO bioavailability.

Gut hormone release and appetite regulation in healthy non-obese participants following oligofructose intake. A dose-escalation study

Prevention of weight gain in adults is a major public health target. Animal experiments have consistently demonstrated a relationship between fermentable carbohydrate intake, such as oligofructose, anorectic gut hormones, and appetite suppression and body weight control. This study was designed to determine the dose of oligofructose which would augment the release of anorectic gut hormones and reduce appetite consistently in non-obese humans. Twelve non-obese participants were recruited for a 5-week dose-escalation study. Following a 9-14-day run-in, participants increased their daily oligofructose intake every week from 15, 25, 35, 45, to 55 g daily. Subjective appetite and side effects were monitored daily. Three-day food diaries were completed every week. Appetite study sessions explored the acute effects of 0, 15, 35, and 55 g oligofructose on appetite-related hormones, glycaemia, subjective appetite, and energy intake. In the home environment, oligofructose suppressed hunger, but did not affect energy intake. Oligofructose dose-dependently increased peptide YY, decreased pancreatic polypeptide and tended to decrease ghrelin, but did not significantly affect appetite profile, energy intake, glucose, insulin, or glucagon-like peptide 1 concentrations during appetite study sessions. In conclusion, oligofructose supplementation at ≥ 35 g/day increased peptide YY and suppressed pancreatic polypeptide and hunger; however, energy intake did not change significantly.

Apple pectin for the reduction of niacin-induced flushing

BACKGROUND

Niacin, or vitamin B3, when used in high doses can significantly improve the levels of all major lipoproteins. Despite these benefits, the use of niacin is greatly limited secondary to benign yet bothersome cutaneous flushing primarily involving the face and upper extremities. Pretreatment with aspirin or other prostaglandin inhibitors has demonstrated significant reductions in niacin-induced flushing (NIF), but other treatment options are needed. Clinical and anecdotal evidence suggests the ingestion of pectin-containing fruits (eg, apple) mitigates NIF; however, clinical trials evaluating this are nonexistent.

OBJECTIVE

That pretreatment with encapsulated apple pectin would limit the incidence, severity, time of initiation, and duration of NIF.

METHODS

We enrolled 100 niacin-naïve subjects (n = 25 per group) and preteated them in a double-blind manner with apple pectin, apple pectin + aspirin, aspirin, or placebo, followed by a one-time 1000 mg dose of niacin extended-release (niacin ER). Subjects then assessed major flushing parameters hourly for the next 6 hours with a validated visual analog scale.

RESULTS

Apple pectin and aspirin each significantly lowered the duration of NIF and produced nonsignificant but positive improvements in all other major flushing parameters compared with placebo.

CONCLUSION

Apple pectin may potentially be an alternative to aspirin for the prevention of NIF. Larger trials are needed to further evaluate the benefit of pectin on NIF.

Digestion of kiwifruit fiber

Dietary fiber affects the digestion and absorption of nutrients in the gastrointestinal tract. Moreover, it is generally believed that fiber largely escapes digestion in the human small intestine and is therefore mainly a substrate for microbial fermentation in the hindgut. Kiwifruit is a food naturally high in dietary fiber, yet the impact of dietary kiwifruit on nutrient availability has not been reported. The digestion of kiwifruit has been investigated but only in in vitro digestion studies. With its naturally high nonstarch polysaccharide content, it would be expected that kiwifruit would possess the characteristics of a good source of fiber for nutrition and health. Kiwifruit contains soluble and nonsoluble fiber components, both of which would be expected to affect the physical attributes of digesta as it transits the gastrointestinal tract. This chapter summarizes fiber digestion in general and current knowledge of kiwifruit fiber digestion in the gastrointestinal tract.

Visão retrospectiva em fibras alimentares com ênfase em beta-glucanas no tratamento do diabetes

Fibra alimentar refere-se aos componentes de plantas ou carboidratos análogos que são resistentes à digestão e absorção no intestino delgado humano. A American Dietetic Association recomenda ingestão de 20-35g de fibras ao dia. Evidências sugerem que uma dieta rica em fibras traz benefícios à manutenção da saúde, redução de risco e tratamento de doenças crônicas como a obesidade, doenças cardiovasculares, diverticulite e diabetes. As fibras são classificadas de acordo com a sua solubilidade em solúveis e insolúveis, com efeitos fisiológicos distintos. As insolúveis são responsáveis pelo aumento do bolo fecal e diminuição do tempo de trânsito intestinal. As solúveis retardam o esvaziamento gástrico e a absorção de glicose diminuindo a glicemia pós-prandial e reduzem o colesterol sérico devido à sua característica física de conferir viscosidade ao conteúdo luminal. As beta-glucanas são fibras altamente viscosas e seu consumo está relacionado à atenuação da resposta glicêmica e insulínica pós-prandial. A beta-glucana tem efeito sobre a degradação do amido e sobre o carboidrato disponível e conseqüentemente, sobre o índice glicêmico dos alimentos ingeridos. Recomenda-se sua ingestão com o objetivo de modular a glicemia e a necessidade de insulina, no tratamento da obesidade, doenças cardiovasculares e do diabetes. Este trabalho visa fornecer uma visão geral sobre beta-glucanas no tratamento do diabetes.

Effects of Passiflora edulis flavicarpa on the radiolabeling of blood constituents, morphology of red blood cells and on the biodistribution of sodium pertechnetate in rats

The aim of this study was to evaluate possible effects of Passiflora edulis flavicarpa (P. flavicarpa) extract on the labeling of blood constituents with (99m)Tc, on the morphology of red blood cells, and on the biodistribution of sodium pertechnetate (sodium (99m)Tc). Male Wistar rats were treated with either P. flavicarpa extract or 0.9% NaCl. After that, radiolabeling of blood constituents, morphological analysis of red blood cells and biodistribution of sodium (99m)Tc was evaluated. Radiolabeling of blood constituents and shape of red blood cells were not modified, but a significant (p<0.05) alteration of the biodistribution of sodium (99m)Tc was observed after treatment with P. flavicarpa extract. Although our results were obtained with animals, they could contribute to reduce the risk of misdiagnosis and/or repetition of the examinations in nuclear medicine.

Effect of a balanced mixture of dietary fibers on gastric emptying, intestinal transit and body weight

BACKGROUND/AIMS

Dietary fibers are frequently included in diets to decrease body weight, but their scarce palatability and the occurrence of meteorism prevent a long-term intake. The aim of this study was to test a mixture of dietary fibers expressly chosen to decrease their negative properties and strengthen their positive effects.

METHODS

In a series of 10 patients with a slight overweight, the effectiveness of a palatable dietary fibers mixture on gastric emptying and intestinal transit was tested with scintigraphic methods. Then, the effects on body weight and digestive sensations and characteristics of defecations, were evaluated for 4 weeks.

RESULTS

The intestinal transit was significantly shortened by the fiber intake, while the gastric emptying was delayed, but not significantly. The body mass index significantly and progressively decreased, whereas the sense of satiation significantly increased. No effect on abdominal bloating was referred, whereas a significant increase in number of defecations with stools of normal consistency was observed. The acceptability of the fiber mixture was good.

CONCLUSIONS

The present research demonstrated that it is possible to prepare a palatable mixture of dietary fibers that maintains the property of decreasing body weight, favors the sense of satiation and accelerates the intestinal transit, with normalization of the stool consistency without the occurrence of meteorism.

Effects of agar and pectin on gastric emptying and post-prandial glycaemic profiles in healthy human volunteers

1. Dietary fibre, such as pectin, delays gastric emptying and may enhance post-prandial glucose tolerance. Agar, which is high in fibre content, is widely used in the traditional Japanese diet. Although long-term diet therapy with agar decreases fasting plasma glucose levels in diabetes, knowledge is lacking about the acute effects of agar on gastric emptying and the post-prandial glycaemic profiles. The present study was designed to investigate the acute effects of agar. 2. Ten healthy male volunteers were studied on three occasions with three different test meals (450 kcal/500 mL): (i) a fibre-free meal; (ii) a meal with 2.0 g agar; or (iii) a meal with 5.2 g pectin. On each occasion, participants underwent a [(13)C]-acetate breath test along with serial blood sampling. To quantify gastric emptying, the half [(13)CO(2)] excretion time (t((1/2)b)) and the time for maximal [(13)CO(2)] excretion rate (t(lag)) were determined. The post-prandial glycaemic response was expressed as an incremental change from the fasting value at each sampling time. Data were analysed using repeated-measures analysis of variance (anova), followed by a post hoc paired Student's t-test with Bonferroni adjustment. 3. The time-course for respiratory [(13)CO(2)] excretion differed significantly among the three test meals (P = 0.0004, anova). Compared with the control meal, [(13)CO(2)] excretion was significantly lower following consumption of the agar meal (between 40 and 105 min post-prandially; P < 0.025, Student's t-test) and the pectin meal (between 40 and 180 min post-prandially; P < 0.025, Student's t-test). Among the three meals, significant differences were found in t((1/2)b) (P = 0.002, anova) and t(lag) (P = 0.011, anova). Compared with the control meal, the agar and pectin meals exhibited a significantly prolonged t((1/2)b) (P = 0.007 and P < 0.0001, respectively, Student's t-test) and t(lag) (P = 0.006 and P = 0.002, respectively, Student's t-test). Neither the agar nor pectin meal affected the post-prandial glucose profile. 4. In healthy adults, agar and pectin delay gastric emptying but have no impact on the post-prandial glucose response.

Effect of formula thickened with locust bean gum on gastric emptying in infants

AIM

We investigated the effects of milk-based formulas thickened with two different concentrations of locust bean gum on gastric emptying in infants with recurrent regurgitation episodes.

METHODS

Thirty-nine infants with three or more episodes of regurgitation per day but no complications who were fed mainly with infant formula were studied. We first compared gastric emptying in infants fed with formulas thickened with two different concentrations of locust bean gum (HL-350, 0.35 g/100 mL; HL-450, 0.45 g/100 mL) or a regular formula (HL-00). To evaluate gastric emptying, we measured antral cross-sectional areas ultrasonographically at various time points after feeding. Next, to investigate the clinical effect of thickened formulas on regurgitation episodes, 27 infants with episodes were assigned randomly to receive HL-350 and HL-00 or HL-450 and HL-00 for 1 week each.

RESULTS

Antral cross-sectional areas at 60, 90, 120 and 150 min with HL-450, and at 60 min with HL-350, were greater than with HL-00. The median gastric emptying rate at 120 min with HL-450 (52.8%) was lower than with HL-00 (97.9%; P = 0.0019), while HL-350 (80.3%) and HL-00 did not differ significantly. The mean number of regurgitation episodes was significantly smaller when infants were fed with either HL-350 or HL-450 than with HL-00.

CONCLUSIONS

HL-450, a thickened formula with typical commercially available concentrations of locust bean gum, slowed gastric emptying in infants with gastroesophageal reflux.

Psyllium decreased serum glucose and glycosylated hemoglobin significantly in diabetic outpatients

Psyllium is a bulk-forming laxative and is high in both fiber and mucilage. The beneficial effect of dietary fiber in the management of type II diabetes, has not been totally demonstrated. The purpose of this study was to determine the plasma-lowering effects of 5.1g b.i.d. of psyllium husk fiber, as an adjunct to dietary and drug therapy on lipid and glucose levels, in patients with type II diabetes. Patients were randomly selected from an outpatient clinic of primary care to participate in a double-blind placebo-controlled study in which Plantago ovata Forsk., or placebo was given in combination with their anti-diabetic drugs. Forty-nine subjects were included in the study that were given diet counseling before the study and then followed for 8 weeks in the treatment period. Fasting plasma glucose (FBS) was measured every 2 weeks, and total plasma cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglyceride (TG), and insulin levels were measured every 4 weeks. Glycosylated hemoglobin (HbA1c) was also measured at the beginning and ending of the study. The test products (psyllium or placebo) were supplied to subjects in identically labeled foil packets containing a 5.1g dose of product, to consume two doses per day, half an hour before breakfast and dinner. Both products were well tolerated, with no serious adverse events related to treatment was reported in either. Better gastric tolerance to metformin was recorded in the psyllium group. FBS, and HbA1c, showed a significant reduction (p<0.05), whereas HDL-C increased significantly (p<0.05) following psyllium treatment. LDL/HDL ratio was significantly decreased (p<0.05). Our results show that 5.1g b.i.d. of psyllium for persons with type II diabetes is safe, well tolerated, and improves glycemic control.

The addition of locust bean gum but not water delayed the gastric emptying rate of a nutrient semisolid meal in healthy subjects

BACKGROUND

Most of the previous studies regarding the effects of gel-forming fibres have considered the gastric emptying of liquid or solid meals after the addition of pectin or guar gum. The influence of locust bean gum, on gastric emptying of nutrient semisolid meals in humans has been less well studied, despite its common occurrence in foods. Using a standardised ultrasound method, this study was aimed at investigating if the gastric emptying in healthy subjects could be influenced by adding locust been gum, a widely used thickening agent, or water directly into a nutrient semisolid test meal.

METHODS

The viscosity of a basic test meal (300 g rice pudding, 330 kcal) was increased by adding Nestargel (6 g, 2.4 kcal), containing viscous dietary fibres (96.5%) provided as seed flour of locust bean gum, and decreased by adding 100 ml of water. Gastric emptying of these three test meals were evaluated in fifteen healthy non-smoking volunteers, using ultrasound measurements of the gastric antral area to estimate the gastric emptying rate (GER).

RESULTS

The median value of GER with the basic test meal (rice pudding) was estimated at 63%, (range 47 to 84%), (the first quartile = 61%, the third quartile = 69%). Increasing the viscosity of the rice pudding by adding Nestargel, resulted in significantly lower gastric emptying rates (p < 0.01), median GER 54%, (range 7 to 71%), (the first quartile = 48%, the third quartile = 60%). When the viscosity of the rice pudding was decreased (basic test meal added with water), the difference in median GER 65%, (range 38 to 79%), (the first quartile = 56%, the third quartile = 71%) was not significantly different (p = 0.28) compared to the GER of the basic test meal.

CONCLUSIONS

We conclude that the addition of locust bean gum to a nutrient semisolid meal has a major impact on gastric emptying by delaying the emptying rate, but that the addition of water to this test meal has no influence on gastric emptying in healthy subjects.

Effects of guar gum, ispaghula and microcrystalline cellulose on abdominal symptoms, gastric emptying, orocaecal transit time and gas production in healthy volunteers

BACKGROUND

Dietary fibres are carbohydrates that resist hydrolysis by human intestinal enzymes but are fermented by colonic microflora. Soluble dietary fibres are fermented by anaerobic bacteria with production of gases, short chain fatty acids and other metabolic products believed to cause symptoms such as bloating, abdominal distension, flatulence. Insoluble fibres are only partially fermented, serving almost exclusively as bulking agents that result in shorter transit time and increased faecal mass.

AIMS

To evaluate effect of a supplementation of a single 5 g dose of dietary fibre to a solid meal on gastric emptying, orocaecal transit time, gas production and symptom genesis, in healthy volunteers. Three different dietary fibres were tested, two soluble (guar gum and ispaghula] and one insoluble (microcrystalline cellulose).

PATIENTS AND METHODS

After a 24-hour low fibre diet, 10 healthy subjects had a standard meal consisting of white bread and one 70 g egg the yolk of which was mixed with 100 mg of 13C octanoic acid and fried. Breath samples were collected for 13CO2 measurements with a mass spectrophotometer and excretion curve (Tlag, T1/2) evaluation. Further breath samples were collected and analysed with a gas chromatograph for the evaluation of H2 and CH4 production and orocaecal transit time. Each evaluation was repeated adding to standard meal, diluted in 300 ml tap water, respectively: a single 5 g dose of microcrystalline cellulose, guar gum or ispaghula. Subjects were asked to report all symptoms experienced from time of meal ingestion over 24 hours, evaluating the intensity.

RESULTS

Dietary fibres did not significantly change gastric emptying (Tlag, T1/2) and orocaecal transit time of standard meal. Subjects experienced more symptoms when meals were supplemented with guar gum (p=0.009 vs standard meal) and ispaghula (p=0.048 vs standard meal). There was a poor, but significant, correlation between gas production and symptoms (r=0. 38, p=0. 01).

CONCLUSIONS

Addition of different dietary fibres to a solid meal did not influence gastric emptying and orocaecal transit time. Microcrystalline cellulose caused fewer symptoms than guar gum and ispaghula probably due to the insoluble nature and the dimensions of the particles of this micronised cellulose.

Effect of pectin on satiety in healthy US Army adults

OBJECTIVE

We tested the hypothesis that pectin, a source of dietary fiber that delays gastric emptying, increases satiety.

METHODS

Male (n = 49) and female (n = 25) US Army employees within normal weight limits were fasted overnight then fed 448 mL of orange juice on 2 separate days followed 4 hours later by 0.473 L of ice cream. On 1 of the 2 days, 5, 10, 15 or 20 g of pectin was mixed with the orange juice. Satiety was measured on a visual analog scale before and at 0, 1, 2, 3 and 4 hours after orange juice and at 0, 30 and 60 minutes after ice cream. Multivariate ANOVA was used to examine satiety as a function of beverage (orange juice vs. orange juice plus pectin), time and pectin dose.

RESULTS

There were significant differences in satiety as a function of beverage (p < 0.001) and time (p < 0.001) but not pectin dose (p = 0.121). The effect lasted up to 4 hours after ingesting pectin and orange juice and for 60 minutes after a second meal consisting of ice cream.

CONCLUSIONS

Pectin in doses as small as 5 g mixed with orange juice increases satiety and can aid in a program to reduce weight by limiting food intake.

Chemistry and uses of pectin--a review

Pectin is an important polysaccharide with applications in foods, pharmaceuticals, and a number of other industries. Its importance in the food sector lies in its ability to form gel in the presence of Ca2+ ions or a solute at low pH. Although the exact mechanism of gel formation is not clear, significant progress has been made in this direction. Depending on the pectin, coordinate bonding with Ca2+ ions or hydrogen bonding and hydrophobic interactions are involved in gel formation. In low-methoxyl pectin, gelation results from ionic linkage via calcium bridges between two carboxyl groups belonging to two different chains in close contact with each other. In high-methoxyl pectin, the cross-linking of pectin molecules involves a combination of hydrogen bonds and hydrophobic interactions between the molecules. A number of factors--pH, presence of other solutes, molecular size, degree of methoxylation, number and arrangement of side chains, and charge density on the molecule--influence the gelation of pectin. In the food industry, pectin is used in jams, jellies, frozen foods, and more recently in low-calorie foods as a fat and/or sugar replacer. In the pharmaceutical industry, it is used to reduce blood cholesterol levels and gastrointestinal disorders. Other applications of pectin include use in edible films, paper substitute, foams and plasticizers, etc. In addition to pectolytic degradation, pectins are susceptible to heat degradation during processing, and the degradation is influenced by the nature of the ions and salts present in the system. Although present in the cell walls of most plants apple pomace and orange peel are the two major sources of commercial pectin due to the poor gelling behavior of pectin from other sources. This paper briefly describes the structure, chemistry of gelation, interactions, and industrial applications soft pectin.

The effect of fat and carbohydrate on plasma glucose, insulin, C-peptide, and triglycerides in normal male subjects

Ten normal subjects were given 50 g starch, or 50 g starch + 50 g fat as a breakfast meal. The starch was given in the form of potato; the fat was given in the form of butter. The meals were ingested at 8 a.m. Plasma glucose, insulin, C-peptide, and triglyceride concentrations were measured at various time points for 4 hours after each meal. The net 4-hour postprandial area responses to the ingested meals were determined using the trapezoid rule, with the fasting glucose concentration, measured at the same time points for 4 hours as a baseline. The glucose area response was 2.2 mmol hour/l following the potato meal. This was significantly reduced following ingestion of the meal containing fat (1.3 mmol hour/l) (p < 0.01). The insulin area response was slightly greater following the meal containing fat (459 pmol hour/l) compared to potato alone (423 pmol hour/l) (p < 0.01). The C-peptide area response following the meal containing fat was 0.80 pmol hour/ml, clearly greater than following potato alone (0.58 pmol hour/ml) (p < 0.01). The triglyceride area response also was much greater following the meal containing fat compared to potato alone (0.74 and 0.08 mmol hour/l, respectively). The mechanism of the attenuated glucose response to carbohydrate ingestion with a fat-containing meal is unknown. It may be due to the release of an enteric hormone that increases glucose disposal, either directly or indirectly, through insulin.