Increased plasma PYY levels following supplementation with the functional fiber PolyGlycopleX in healthy adults

Enteroendocrine cell differentiation and function in the intestine

PURPOSE OF REVIEW

The intestinal enteroendocrine cells (EECs) are specialized hormone-secreting cells that respond to both circulating and luminal cues. Collectively, EECs constitute the largest endocrine organ of the body and signal to a multitude of targets including locally to neighboring intestinal cells, enteric neurons, as well as systemically to other organs, such as the pancreas and brain. To accomplish their wide range of downstream signaling effects, EECs secrete multiple hormones; however, the mechanisms that influence EEC development in the embryo and differentiation in adults are not well defined.

RECENT FINDINGS

This review highlights the recent discoveries in EEC differentiation and function while also discussing newly revealed roles of transcription factors and signaling networks involved in the allocation of EEC subtypes that were discovered using a combination of novel intestinal model systems and genetic sequencing. We also discuss the potential of these new experimental models that study the mechanisms regulating EEC function and development both to uncover novel therapeutic targets.

SUMMARY

Several EEC hormones are being used to treat various metabolic disorders, such as type 2 diabetes and obesity. Therefore, understanding the signaling pathways and gene regulatory networks that facilitate EEC formation is paramount to the development of novel therapies.

The Effect of Isolated and Synthetic Dietary Fibers on Markers of Metabolic Diseases in Human Intervention Studies: A Systematic Review

Observational studies provide strong evidence for the health benefits of dietary fiber (DF) intake; however, human intervention studies that supplement isolated and synthetic DFs have shown inconsistent results. Therefore, we conducted a systematic review to summarize the effects of DF supplementation on immunometabolic disease markers in intervention studies in healthy adults, and considered the role of DF dose, DF physicochemical properties, intervention duration, and the placebo used. Five databases were searched for studies published from 1990 to 2018 that assessed the effect of DF on immunometabolic markers. Eligible studies were those that supplemented isolated or synthetic DFs for ≥2 wk and reported baseline data to assess the effect of the placebo. In total, 77 publications were included. DF supplementation reduced total cholesterol (TC), LDL cholesterol, HOMA-IR, and insulin AUC in 36-49% of interventions. In contrast, <20% of the interventions reduced C-reactive protein (CRP), IL-6, glucose, glucose AUC, insulin, HDL cholesterol, and triglycerides. A higher proportion of interventions showed an effect if they used higher DF doses for CRP, TC, and LDL cholesterol (40-63%), viscous and mixed plant cell wall DFs for TC and LDL cholesterol (>50%), and longer intervention durations for CRP and glucose (50%). Half of the placebo-controlled studies used digestible carbohydrates as the placebo, which confounded findings for IL-6, glucose AUC, and insulin AUC. In conclusion, interventions with isolated and synthetic DFs resulted mainly in improved cholesterol concentrations and an attenuation of insulin resistance, whereas markers of dysglycemia and inflammation were largely unaffected. Although more research is needed to make reliable recommendations, a more targeted supplementation of DF with specific physicochemical properties at higher doses and for longer durations shows promise in enhancing several of its health effects.

Effect of Fibre-Enriched Orange Juice on Postprandial Glycaemic Response and Satiety in Healthy Individuals: An Acute, Randomised, Placebo-Controlled, Double-Blind, Crossover Study

Background: Consumption of fibre-enriched orange juice may be an appropriate way to supplement daily fibre intake and achieve beneficial effects on metabolic health. The present study aimed to assess the short-term effects of fibre-enriched orange juice on postprandial metabolism and satiety in a healthy adult population. Methods: In this double-blind, randomised, placebo-controlled, crossover study 10 healthy subjects underwent two one-day trials in which they consumed an orange juice beverage containing 1.4 g/100 mL of citrus fibre (29.3% soluble and 41.9% insoluble) or a placebo (regular orange juice without added fibre). Postprandial glucose, insulin, gut hormones (GLP1, GIP and ghrelin), leptin and qualitative appetite/satiety assessment were measured every 15 or 30 min over the 120 min test period. Results: The fibre-enriched orange juice decreased postprandial serum glucose and circulating insulin levels at 15 min compared with the placebo. In addition, after intake of the fibre-enriched juice, a significant effect on qualitative feelings of satiety and fullness was observed at 15 and 120 min, and was accompanied by a significant decrease in GLP1 response at 15 min. No significant changes were observed in leptin, GIP and ghrelin after juice intake. Conclusions: In healthy individuals, a single acute consumption of fibre-enriched orange juice has short-term beneficial effects on postprandial glycaemia, circulating insulin levels and satiety through GLP1 secretion.

Ratios of soluble and insoluble dietary fibers on satiety and energy intake in overweight pre- and postmenopausal women

BACKGROUND: Fibers’ properties impact different mechanisms involved in satiety and energy intake regulation and metabolic outcomes.

OBJECTIVE: Evaluate the effect of fiber types and menopausal status on satiety and metabolic responses in overweight women.

METHODS: In a randomized within-subjects design, 19 overweight/obese women [9 premenopausal and 10 postmenopausal] consumed 3 preloads that varied by fiber content and source: 1) 3:1 ratio of soluble:insoluble fiber (SF), 2) 1:3 ratio of soluble:insoluble fiber (IF), 3) no fiber control (NFC). Subjective satiety, cholecystokinin (CCK), glucose, insulin, and triglyceride (TG) were measured for 3 h post-preload followed by in-lab ad libitum test meal and 32 hour food intake monitoring.

RESULTS: Significant preload, time and preload by menopausal status interaction was apparent for hunger and fullness (p < 0.05 for both) with SF preload predominantly more satiating in postmenopausal women. CCK and insulin were significantly lower after SF preload (p < 0.0001 for both). Post-preload glucose responses differed by menopausal status: postmenopausal women distinguished between fiber types unlike premenopausal women (p = 0.02). TG was significantly elevated after the IF preload compared to NFC and SF (p = 0.007 and p = 0.008, respectively).

CONCLUSIONS:Customized/personalized dietary recommendations for women during their premenopausal and postmenopausal years can help maximize metabolic and appetite control.

Effect of Fibre Supplementation on Body Weight and Composition, Frequency of Eating and Dietary Choice in Overweight Individuals

Fibre supplementation can potentially reduce energy intake and contribute to weight loss. The mechanism may be reduced frequency of eating, resulting in reduced food consumption. The objective of this research was to determine the effectiveness of fibre supplementation with PolyGlycopleX® (PGX®), on body weight and composition, frequency of eating and dietary intake in 118 overweight adults. In a three-arm, parallel, blind, randomised controlled trial participants were randomised to one of three groups; 4.5 g PGX as softgels (PGXS), 5 g PGX granules (PGXG) or 5 g rice flour (RF) control. Prior to supplementation and at 12 weeks, participants captured before and after images of all food and beverages consumed within 4 days using a mobile food record app (mFR). The mFR images were analysed for food group serving sizes and number of eating occasions. In the PGXG group, per-protocol analysis [corrected] analysis showed there was a significant reduction in waist circumference (2.5 cm; p = 0.003). Subgroup analysis showed that PGXG supplementation at the recommended dose resulted in a reduction in body weight (-1.4 ± 0.10 kg, p < 0.01), body mass index (BMI) reduction (-0.5 ± 0.10, p < 0.01), reduced number of eating occasions (-1.4 ± 1.2, p < 0.01) and a reduced intake of grain food (-1.52 ± 1.84 serves, p = 0.019). PGXG at the recommended dose resulted in a reduction in weight and BMI which was significantly greater than that for RF (p = 0.001). These results demonstrate the potential benefits of PGX fibre in controlling frequency of eating and in weight loss.

Effect on Insulin, Glucose and Lipids in Overweight/Obese Australian Adults of 12 Months Consumption of Two Different Fibre Supplements in a Randomised Trial

Higher fibre intakes are associated with risk reduction for chronic diseases. This study investigated the effects of supplementation with PolyGlycopleX^® (PGX), a complexed polysaccharide, on insulin, glucose and lipids in overweight and obese individuals. In this double-blind 12 months study, participants were randomised into three groups: control (rice flour); PGX or psyllium (PSY). Participants followed their usual lifestyle and diet but consumed 5 g of their supplement before meals. Insulin was significantly lower in the PGX and PSY groups compared to control at 3 and 6 months and in the PSY group compared to control at 12 months. Serum glucose was significantly lower in the PGX group at 3 months compared to control. Total cholesterol was significantly lower in the PGX and PSY groups compared to control at 3 and 6 months. High density lipoprotein (HDL) cholesterol was significantly increased in the PGX group compared to control at 12 months. low density lipoprotein (LDL) cholesterol was significantly lower in the PGX group at 3 and 6 months compared to control and in the PSY group at 3 months compared to control. A simple strategy of fibre supplementation may offer an effective solution to glucose, insulin and lipid management without the need for other nutrient modification.

Effect on body weight and composition in overweight/obese Australian adults over 12 months consumption of two different types of fibre supplementation in a randomized trial

BACKGROUND/OBJECTIVES

Higher fibre intakes are associated with risk reduction for chronic diseases. However, many people find difficulty in consuming sufficient fibre through their diet. Supplements may be an effective alternative. We aimed to investigate the effects of PolyGlycopleX® (PGX®), a proprietary polysaccharide complex and a proprietary Psyllium product (PgxSyl™) (PSY) on diet, body weight and composition in overweight and obese individuals.

SUBJECTS/METHODS

This was a double-blind 52 weeks study with 159 people randomized to 3 groups: control (rice flour); PGX (PGX) and proprietary psyllium (PSY). Participants did not change any of their usual habits or diet except they consumed 5 g of supplement taken with a total of 500 ml of water 5-10 min before meals.

RESULTS

Weight was significantly lower in the PGX group compared to control at 3 (-1.6 kg [0.57, 2.67, p = 0.003]), 6 (-2.6 kg [1.01, 4.13, p = 0.001]) and 12 months (-2.6 kg [0.59, 4.64, p = 0.012]) and in the PSY group compared to control group at 3 (-1.1 kg [0.07, 2.12, p = 0.037]) and 6 months (-2.4 kg [0.95, 3.93, p = 0.002]). This was a difference of - 2.8% for the PGX group and - 1.5% for the PSY group compared to control after 12 months supplementation. Body Fat was significantly lower in PGX compared to control at 6 (-1.8 kg [0.63, 2.95, p = 0.003]) and 12 months (-1.9 kg [0.43, 3.36, p = 0.012]) and in PSY compared to control at 6 (-1.9 kg [0.84, 3.04, p = 0.001]) and 12 months (-1.4 kg [0.08, 2.71, p = 0.038]).

CONCLUSIONS

PGX was better than PSY at maintaining dietary changes and weight loss over the 12 month intervention period, with no change to exercise. A simple strategy of PGX supplementation may offer an effective solution to long-term weight-loss and then management without the need for other nutrient modification.

TRIAL REGISTRATION

ANZCTR: ACTRN12611000415909. Registered 20 April 2011.

Effects of Dietary Fibre (Pectin) and/or Increased Protein (Casein or Pea) on Satiety, Body Weight, Adiposity and Caecal Fermentation in High Fat Diet-Induced Obese Rats

Dietary constituents that suppress appetite, such as dietary fibre and protein, may aid weight loss in obesity. The soluble fermentable dietary fibre pectin promotes satiety and decreases adiposity in diet-induced obese rats but effects of increased protein are unknown. Adult diet-induced obese rats reared on high fat diet (45% energy from fat) were given experimental diets ad libitum for 4 weeks (n = 8/group): high fat control, high fat with high protein (40% energy) as casein or pea protein, or these diets with added 10% w/w pectin. Dietary pectin, but not high protein, decreased food intake by 23% and induced 23% body fat loss, leading to 12% lower final body weight and 44% lower total body fat mass than controls. Plasma concentrations of satiety hormones PYY and total GLP-1 were increased by dietary pectin (168% and 151%, respectively) but not by high protein. Plasma leptin was decreased by 62% on pectin diets and 38% on high pea (but not casein) protein, while plasma insulin was decreased by 44% on pectin, 38% on high pea and 18% on high casein protein diets. Caecal weight and short-chain fatty acid concentrations in the caecum were increased in pectin-fed and high pea protein groups: caecal succinate was increased by pectin (900%), acetate and propionate by pectin (123% and 118%, respectively) and pea protein (147% and 144%, respectively), and butyrate only by pea protein (309%). Caecal branched-chain fatty acid concentrations were decreased by pectin (down 78%) but increased by pea protein (164%). Therefore, the soluble fermentable fibre pectin appeared more effective than high protein for increasing satiety and decreasing caloric intake and adiposity while on high fat diet, and produced a fermentation environment more likely to promote hindgut health. Altogether these data indicate that high fibre may be better than high protein for weight (fat) loss in obesity.

Consumption of the Soluble Dietary Fibre Complex PolyGlycopleX(®) Reduces Glycaemia and Increases Satiety of a Standard Meal Postprandially

The effect of consumption of PolyGlycopleX^® (PGX^®) was compared to wheat dextrin (WD) in combination with a standard meal, on postprandial satiety and glycaemia in a double-blind, randomised crossover trial, of 14 healthy subjects trained as a satiety panel. At each of six two-hour satiety sessions, subjects consumed one of three different test meals on two separate occasions. The test meals were: a standard meal plus 5 g PGX; a standard meal plus 4.5 g of PGX as softgels; and a standard meal plus 5 g of WD. Subjects recorded fullness using a labelled magnitude scale at 0, 15, 30, 45, 60, 90, and 120 min and the total area under the curve (AUC), mean fullness vs. time was calculated. The meals with PGX (in granular and softgel form) gave higher satiety (AUC) (477 ± 121 and 454 ± 242 cm·min), than the meal with WD (215 ± 261 cm·min) (p < 0.001). Subjects had blood glucose levels measured after the meals with PGX (granules) and WD. Glucose response (AUC) was significantly lower (p < 0.001) after the PGX meal than for the WD meal.  The high viscosity reported for PGX is a likely mechanism behind the significant satiety and blood glucose modulating effects observed in this study.

Effects of a viscous-fibre supplemented evening meal and the following un-supplemented breakfast on post-prandial satiety responses in healthy women

The post-prandial satiety response and "second-meal effect" of a viscous fibre supplement PolyGlycopleX(®) (PGX(®)) was evaluated in a single-blind, randomised controlled crossover study of 14 healthy adult women. The two hour post-prandial satiety response, expressed as the area under the curve (AUC) of perceived hunger/fullness score versus post-prandial time, of a standardised evening meal with concurrent intake of either PGX softgel or rice flour softgel (control) was determined. On the following morning, after an overnight fast, the four hour satiety response to a standardised breakfast with no softgel supplementation was assessed. A significantly higher satiety response (AUC) to the standard dinner for the PGX-supplemented dinner compared with the control dinner (p=0.001) was found. No significant difference (p=0.09) was observed in the satiety response (AUC) of the breakfast regardless of which supplemented-dinner had been consumed prior, however the p value indicated a trend towards a higher response to the breakfast following the PGX-supplemented dinner. The fullness scores of the breakfast following the PGX-supplemented dinner at 15, 30, 90, 120, 150, 180, 210 and 240min post-prandial were significantly higher than those for the breakfast following the control dinner (p=<0.001, 0.007, 0.009, 0.009, 0.049, 0.03, 0.003 and <0.001 respectively). PGX supplementation at dinner increased the satiety effects of both the dinner itself and the subsequent un-supplemented breakfast; a "second meal effect" indicting the potential for this fibre supplement to induce extended satiety.

Soluble dietary fiber (Fibersol-2) decreased hunger and increased satiety hormones in humans when ingested with a meal

We hypothesized that a digestion-resistant maltodextrin, Fibersol-2 (Archer Daniels Midland/Matsutani LLC, Decatur, IL, USA) may impact satiety by decreasing hunger, prolonging satiation, and/or increasing peripheral satiety signals. In a randomized, double-blind, placebo-controlled crossover study, healthy subjects (9 men and 10 women) underwent 3 treatments in which they consumed a standardized meal with a tea containing 0, 5, or 10 g of Fibersol-2. A visual analog scale questionnaire was given in 30-minute intervals to measure subjective appetite and satiety. Blood was drawn just before the meal (time 0) and at 30, 60, 90, 120, 180, and 240 minutes after meal for measurements of plasma ghrelin, cholecystokinin, gastrin, peptide YY, gastric inhibitory polypeptide, and glucagon-like peptide-1, all by enzyme-linked immunosorbent assay. There were significant delays in hunger and increased satiety for 1.5 to 2 hours after treatment with 10 g of Fibersol-2. These delays did not occur after ingesting 0 or 5 g Fibersol-2 at any time. Control and 5 g Fibersol-2 treatments did not suppress increases in hunger postmeal; hunger scores increased and satiety scores decreased significantly (P < .05) at all time points relative to the first postmeal assessment. Plasma peptide YY and glucagon-like peptide-1 were significantly increased by the ingestion of meal with tea containing 10 g Fibersol-2 compared with 0 or 5 g Fibersol-2 (P < .05). This study demonstrated that 10 g Fibersol-2 with a meal stimulated production of satiety hormones and enhanced satiety.

Effect of the novel functional fibre, polyglycoplex (PGX), on body weight and metabolic parameters: A systematic review of randomized clinical trials

BACKGROUND & AIMS

Hundreds of dietary supplements are marketed as weight loss pills, but the evidence for effectiveness for most is unproven. The objective of this review was to critically appraise and evaluate the evidence from published randomized clinical trials (RCTs) examining the effectiveness of polyglycoplex (PGX), a novel functional fibre, on body weight and metabolic parameters.

METHODS

We conducted electronic searches in Medline, Embase, Amed, Cinahl and The Cochrane Library. Only double-blinded RCTs were considered for inclusion. The reporting quality of included studies was assessed using the Cochrane criteria. Two reviewers independently determined eligibility, assessed the quality of reporting, and extracted the data.

RESULTS

We included four RCTs with a total of 217 participants. The RCTs varied in the quality of their reporting. The evidence from the RCTs suggested that PGX has no significant effects on body weight; however, significant reductions were noted for total and LDL cholesterol. Adverse events reported included diarrhea and abdominal bloating.

CONCLUSION

The evidence from available RCTs does not indicate that PGX intake causes reductions in body weight. PGX may cause reductions in total and LDL cholesterol. Few trials examining the effects of PGX have been conducted; they are characterized by small sample sizes, deficiencies in reporting quality, and are funded by a single manufacturer. Future clinical trials evaluating its effect should be adequately powered and better reported.

Factors affecting circulating levels of peptide YY in humans: a comprehensive review

As obesity continues to be a global epidemic, research into the mechanisms of hunger and satiety and how those signals act to regulate energy homeostasis persists. Peptide YY (PYY) is an acute satiety signal released upon nutrient ingestion and has been shown to decrease food intake when administered exogenously. More recently, investigators have studied how different factors influence PYY release and circulating levels in humans. Some of these factors include exercise, macronutrient composition of the diet, body-weight status, adiposity levels, sex, race and ageing. The present article provides a succinct and comprehensive review of the recent literature published on the different factors that influence PYY release and circulating levels in humans. Where human data are insufficient, evidence in animal or cell models is summarised. Additionally, the present review explores the recent findings on PYY responses to different dietary fatty acids and how this new line of research will make an impact on future studies on PYY. Human demographics, such as sex and age, do not appear to influence PYY levels. Conversely, adiposity or BMI, race and acute exercise all influence circulating PYY levels. Both dietary fat and protein strongly stimulate PYY release. Furthermore, MUFA appear to result in a smaller PYY response compared with SFA and PUFA. PYY levels appear to be affected by acute exercise, macronutrient composition, adiposity, race and the composition of fatty acids from dietary fat.

High-fiber rye diet increases ileal excretion of energy and macronutrients compared with low-fiber wheat diet independent of meal frequency in ileostomy subjects

Background

Whole-grain foods and cereal dietary fiber intake is associated with lower body weight. This may partly result from lower energy utilization of high-fiber diets.

Objective

In the present study, the impact on ileal excretion of energy and macronutrients in response to a rye bread high-fiber diet compared to a refined wheat low-fiber diet was investigated. Furthermore, the effect of meal frequency on apparent absorption of nutrients was studied for the first time.

Design

Ten participants that had undergone ileostomy consumed standardized iso-caloric diets, including low-fiber wheat bread (20 g dietary fiber per day) for 2 weeks followed by high-fiber rye bread (52 g dietary fiber per day) for 2 weeks. The diets were consumed in an ordinary (three meals per day) and a nibbling (seven meals per day) meal frequency in a cross-over design. Ileal effluents were collected during 24 h at the third day of each of the four dietary periods and analyzed for gross energy and nutrient contents.

Results

The results showed that intake of rye bread high-fiber diet compared to the refined wheat low-fiber diet caused an increase in ileal excretion of energy and macronutrients. The effect was independent of meal frequency. This suggests that a high intake of rye may result in lower availability of macronutrients for small intestinal digestion and absorption. A regular intake of rye may therefore have implications for weight management.

Meal replacements and fibre supplement as a strategy for weight loss. Proprietary PGX® meal replacement and PGX® fibre supplement in addition to a calorie-restricted diet to achieve weight loss in a clinical setting

Meal replacements and viscous soluble fibre represent safe and sustainable aids for weight loss. Our purpose was to determine if PGX® meal replacements and PGX(®) fibre complex in combination with a calorie-restricted diet would aid in weight loss in a clinical setting. Fifty-two overweight and obese participants (49 women, 3 men; average age 47.1 years) with a mean body mass index (BMI) of 33.8 ± 6.4 kg/m(2) consumed 57 g of proprietary PGX® meal replacement product at breakfast and another 57 g at lunch for 12 weeks. In addition to the meal replacements, they were also asked to consume 5 g/day of PGX® fibre in the form of granules, powder or capsules together with 250 mlwater. A registered dietician recommended low-fat, low-glycaemic-index foods for snacks and the dinner menus such that each volunteer was consuming a total of 1200 kcal/day. All participants (n = 52) lost a significant amount of weight from baseline (-4.69 ± 3.73 kg), which was further reflected in the reductions in their waist (-7.11 ± 6.35 cm) and hip circumference (-5.59 ± 3.58 cm) over the 12-week study (p < 0.0001). BMI scores (n = 51) were reduced by 1.6 ± 1.4 kg/m(2). The use of PGX® meal replacements and PGX(®) fibre along with a controlled dietary caloric intake is of benefit for short-term weight loss.

Decreasing cardiovascular risk factors in obese individuals using a combination of PGX® meal replacements and PGX® granules in a 12-week clinical weight modification program

In this open, clinically based, weight modification program, we determined in six sedentary obese adults (five women; one male; age range 30-62 years) that the combination of a modified calorie diet plus PGX® meal replacement and PGX® supplementation resulted in a significant reduction in several cardiovascular risk factors over a 12-week time period. This included a significant improvement in lipids (-0.98 mmol/l LDL-C), reduction in average weight (-9.2 kg), mean reduction in fat (-4.1%) and an increase in fat-free mass (2.8%).

Food ingredients as anti-obesity agents: a review

Overweight and obesity have a major impact on global health; their prevalence has rapidly increased in all industrialized countries in the past few decades and diabetes and hypertension are their direct consequences. Pharmacotherapy provides reinforcement for obesity treatment, but should be an adjunctive support to diet, exercise, and lifestyle modification. At present, only orlistat and sibutramine have been approved by the US Food and Drug Administration for long-term use, but sibutramine was withdrawn for sale by the European Medicines Agency. The development of functional foods for the prevention and/or treatment of obesity suppose an opportunity for the food market and involve the knowledge of the mechanisms of appetite and energy expenditure as well as the metabolic sensation of satiety. Strategies for weight control management affect gut hormones as potential targets for the appetite metabolic regulation, stimulation of energy expenditure (thermogenesis), and modifications in the metabolic activity of the gut microbiota. Functional foods for obesity may also include bioactive fatty acids, phenolic compounds, soybean, plant sterols, dietary calcium, and dietary fiber. This review intends to offer an overview of the present situation of the anti-obesity agents currently used in dietary therapy as well as some functional food ingredients with potentially anti-obesity effects.

Sitagliptin reduces hyperglycemia and increases satiety hormone secretion more effectively when used with a novel polysaccharide in obese Zucker rats

The novel polysaccharide (NPS) PolyGlycopleX (PGX) has been shown to reduce glycemia. Pharmacological treatment with sitagliptin, a dipeptidyl peptidase 4 (DPP4) inhibitor, also reduces glycemia by increasing glucagon-like peptide-1 (GLP-1). Our objective was to determine if using NPS in combination with sitagliptin reduces hyperglycemia in Zucker diabetic fatty (ZDF) rats more so than either treatment alone. Male ZDF rats were randomized to: 1) cellulose/vehicle [control (C)]; 2) NPS (5% wt:wt)/vehicle (NPS); 3) cellulose/sitagliptin [10 mg/(kg · d) (S)]; or 4) NPS (5%) + S [10 mg/(kg · d) (NPS+S)]. Glucose tolerance, adiposity, satiety hormones, and mechanisms related to DPP4 activity and hepatic and pancreatic histology were examined. A clinically relevant reduction in hyperglycemia occurred in the rats treated with NPS+S (P = 0.001) compared with NPS and S alone. Blood glucose, measured weekly in fed and feed-deprived rats and during an oral glucose tolerance test, was lower in the NPS+S group compared with all other groups (all P = 0.001). At wk 6, glycated hemoglobin was lower in the NPS+S group than in the C and S (P = 0.001) and NPS (P = 0.06) groups. PGX (P = 0.001) and S (P = 0.014) contributed to increased lean mass. Active GLP-1 was increased by S (P = 0.001) and GIP was increased by NPS (P = 0.001). Plasma DPP4 activity was lower in the NPS+S and S groups than in the NPS and C groups (P = 0.007). Insulin secretion and β-cell mass was increased with NPS (P < 0.05). NPS alone reduced LDL cholesterol and hepatic steatosis (P < 0.01). Independently, NPS and S improve several metabolic outcomes in ZDF rats, but combined, their ability to markedly reduce glycemia suggests they may be a promising dietary/pharmacological co-therapy for type 2 diabetes management.

Is There a Place for Dietary Fiber Supplements in Weight Management?

Inadequate dietary fiber intake is common in modern diets, especially in children. Epidemiological and experimental evidence point to a significant association between a lack of fiber intake and ischemic heart disease, stroke atherosclerosis, type 2 diabetes, overweight and obesity, insulin resistance, hypertension, dyslipidemia, as well as gastrointestinal disorders such as diverticulosis, irritable bowel disease, colon cancer, and cholelithiasis. The physiological effects of fiber relate to the physical properties of volume, viscosity, and water-holding capacity that the fiber imparts to food leading to important influences over the energy density of food. Beyond these physical properties, fiber directly impacts a complex array of microbiological, biochemical, and neurohormonal effects directly through modification of the kinetics of digestion and through its metabolism into constituents such as short chain fatty acids, which are both energy substrates and important enteroendocrine ligands. Of particular interest to clinicians is the important role dietary fiber plays in glucoregulation, appetite, and satiety. Supplementation of the diet with highly functional fibers may prove to play an important role in long-term obesity management.

Faecal short chain fatty acids in healthy subjects participating in a randomised controlled trial examining a soluble highly viscous polysaccharide versus control

BACKGROUND

Short chain fatty acids (SCFA) are produced by the bacterial fermentation of dietary fibre and have been linked with intestinal health. The present study examined faecal SCFA concentrations in subjects consuming a novel soluble highly viscous polysaccharide (HVP) or control for 3 weeks. A total of 54 healthy adults participated in a randomised, double-blind, placebo-controlled study.

METHODS

Subjects were randomised to consume HVP or control (skim milk powder). A dose of 5 g day(-1) was consumed in the first week, followed by 10 g day(-1) in the second and third weeks (n = 27 per group). The primary outcome was SCFA concentrations in faecal samples collected at baseline (visit 1, V1), at 1 week (V2) and at 3 week (V3).

RESULTS

The reduction in faecal acetate from V1 to V3 in control subjects was not observed in subjects consuming HVP. There were no differences in propionate, butyrate, valerate or caproate concentrations. There was a significant treatment effect (P = 0.03) for total SCFA, with higher concentrations observed in subjects consuming HVP versus control.

CONCLUSIONS

HVP is a viscous functional fibre that may influence gut microbial fermentation. Further work is warranted to examine the fermentative properties of HVP and possible links with appetite regulation and reduced serum low-density lipoprotein cholesterol concentrations.

Effect of PGX, a novel functional fibre supplement, on subjective ratings of appetite in overweight and obese women consuming a 3-day structured, low-calorie diet

Introduction:

Dietary factors that help control perceived hunger might improve adherence to calorie-reduced diets.

Objectives:

The objective of the study was to investigate the effect of supplementing a three-day, low-calorie diet with PolyGlycopleX (PGX), a highly viscous fibre, on subjective ratings of appetite compared with a placebo.

Methods:

In a double-blind crossover design with a 3-week washout, 45 women (aged 38±9 years, body mass index 29.9±2.8 kg m⁻²) were randomised to consume a 1000-kcal per day diet for 3 days, supplemented with 5 g of PGX or placebo at each of breakfast, lunch and dinner. Subjective appetite was assessed using 100 mm visual analogue scales that were completed daily before, between and after consumption of meals.

Results:

Thirty-five women completed the study. Consumption of PGX compared with placebo led to significantly lower mean area under the curve for hunger on day 3 (440.4 versus 375.4; P=0.048), prospective consumption on day 3 (471.0 versus 401.8; P=0.017) and the overall 3-day average (468.6 versus 420.2; P=0.026). More specifically, on day 3 PGX significantly reduced total appetite, hunger, desire to eat and prospective consumption for 2.5 and 4.5 h after lunch and before dinner times, with hunger also being reduced 2.5 h after dinner (P<0.05).

Conclusion:

The results show that adding 5 g of PGX to meals during consumption of a low-calorie diet reduces subjective ratings of prospective consumption and increases the feelings of satiety, especially during afternoon and evening. This highly viscous polysaccharide may be a useful adjunct to weight-loss interventions involving significant caloric reductions.

Beta glucan: health benefits in obesity and metabolic syndrome

Despite the lack of international agreement regarding the definition and classification of fiber, there is established evidence on the role of dietary fibers in obesity and metabolic syndrome. Beta glucan (β-glucan) is a soluble fiber readily available from oat and barley grains that has been gaining interest due to its multiple functional and bioactive properties. Its beneficial role in insulin resistance, dyslipidemia, hypertension, and obesity is being continuously documented. The fermentability of β-glucans and their ability to form highly viscous solutions in the human gut may constitute the basis of their health benefits. Consequently, the applicability of β-glucan as a food ingredient is being widely considered with the dual purposes of increasing the fiber content of food products and enhancing their health properties. Therefore, this paper explores the role of β-glucans in the prevention and treatment of characteristics of the metabolic syndrome, their underlying mechanisms of action, and their potential in food applications.

Effects of added PGX®, a novel functional fibre, on the glycaemic index of starchy foods

The development of lower-glycaemic index (GI) foods requires simple, palatable and healthy strategies. The objective of the present study was to determine the most effective dose of a novel viscous fibre supplement (PGX®) to be added to starchy foods to reduce their GI. Healthy subjects (n 10) consumed glucose sugar (50 g in water × 3) and six starchy foods with a range of GI values (52–72) along with 0 (inert fibre), 2·5 or 5 g granular PGX® dissolved in 250 ml water. GI testing according to ISO Standard 26 642-2010 was used to determine the reduction in GI. PGX® significantly reduced the GI of all six foods (P < 0·001), with an average reduction of 19 % for the 2·5 g dose and 30 % for the 5 g dose, equivalent to a reducing the GI by 7 and 15 units, respectively. Consuming small quantities of the novel functional fibre PGX®, mixed with water at the start of a meal, is an effective strategy to reduce the GI of common foods.

Effects of the Soluble Fiber Complex PolyGlycopleX on Glucose Homeostasis and Body Weight in Young Zucker Diabetic Rats

Dietary fiber can reduce insulin resistance, body weight, and hyperlipidemia depending on fiber type, water solubility, and viscosity. PolyGlycopleX(®) (PGX(®)) is a natural, novel water soluble, non-starch polysaccharide complex that with water forms a highly viscous gel compared to other naturally occurring dietary fiber. We determined the effect of dietary PGX(®) vs. cellulose and inulin on the early development of insulin resistance, body weight, hyperlipidemia, and glycemia-induced tissue damage in young Zucker diabetic rats (ZDFs) in fasted and non-fasted states. ZDFs (5 weeks old) were fed a diet containing 5% (wgt/wgt) cellulose, inulin, or PGX(®) for 8 weeks. Body weight, lipids, insulin, and glucose levels were determined throughout the study and homeostasis model assessment (HOMA) was used to measure insulin sensitivity throughout the study in fasted animals. At study termination, insulin sensitivity (oral glucose tolerance test, OGTT) and kidney, liver, and pancreatic histopathology were determined. Body weight and food intake were significantly reduced by PGX(®) vs. inulin and cellulose. Serum insulin in fasted and non-fasted states was significantly reduced by PGX(®) as was non-fasted blood glucose. Insulin resistance, measured as a HOMA score, was significantly reduced by PGX(®) in weeks 5 through 8 as well as terminal OGTT scores in fed and fasted states. Serum total cholesterol was also significantly reduced by PGX(®). PGX(®) significantly reduced histological kidney and hepatic damage in addition to reduced hepatic steatosis and cholestasis. A greater mass of pancreatic β-cells was found in the PGX(®) group. PGX(®) therefore may be a useful dietary additive in the control of the development of the early development of the metabolic syndrome.

Effects of a 3-month supplementation with a novel soluble highly viscous polysaccharide on anthropometry and blood lipids in nondieting overweight or obese adults

BACKGROUND

High viscosity fibre is known to exert many beneficial effects on appetite and metabolism. It could potentially help in weight management, in dieting or nondieting individuals. The present study investigated the effects of the daily intake of a novel high viscosity polysaccharide (HVP) over 3 months in nondieting obese or overweight men and women.

METHODS

The study comprised a double-blind, randomised controlled clinical trial. Participants ingested 5-15 g per day of either HVP (n = 29, experimental group) or inulin (n = 30, control group) for 15 weeks. Changes in anthropometry (weight, waist and hip circumferences), blood lipids and glucose tolerance were studied from the beginning to the end of administration. Compliance and tolerance were examined.

RESULTS

Differences appeared between HVP and inulin supplementation in female participants only. Mean (SD) decreases in body weight [1.6 (3.2) kg; approximately 2% of initial weight] and hip circumference [2.8 (3.6 ) cm] occurred in women of the HVP group but not in controls (Time × Group interactions, P ≤ 0.002). Total, high-density lipoprotein and low-density lipoprotein-cholesterol were lower at the end of supplementation in the women of the HVP group compared to controls (P ≤ 0.021). No effect appeared in waist circumference and triacylglycerol. No difference was noted in the number or severity of the adverse effects reported in both groups. Adverse effects were mild and agreed with commonly reported reactions to intake of dietary fibre.

CONCLUSIONS

Beneficial although modest effects appeared after several weeks of daily HVP intake in nondieting obese or overweight women. The effects of HVP should be investigated in the context of a weight loss programme.