Effect of fat replacement by inulin or lupin-kernel fibre on sausage patty acceptability, post-meal perceptions of satiety and food intake in men

Gut microbiota fermentation of prebiotics increases satietogenic and incretin gut peptide production with consequences for appetite sensation and glucose response after a meal

BACKGROUND

We have previously shown that gut microbial fermentation of prebiotics promotes satiety and lowers hunger and energy intake in humans. In rodents, these effects are associated with an increase in plasma gut peptide concentrations, which are involved in appetite regulation and glucose homeostasis.

OBJECTIVE

Our aim was to examine the effects of prebiotic supplementation on satiety and related hormones during a test meal for human volunteers by using a noninvasive micromethod for blood sampling to measure plasma gut peptide concentrations.

DESIGN

This study was a randomized, double-blind, parallel, placebo-controlled trial. A total of 10 healthy adults (5 men and 5 women) were randomly assigned to groups that received either 16 g prebiotics/d or 16 g dextrin maltose/d for 2 wk. Meal tolerance tests were performed in the morning to measure the following: hydrogen breath test, satiety, glucose homeostasis, and related hormone response.

RESULTS

We show that the prebiotic treatment increased breath-hydrogen excretion (a marker of gut microbiota fermentation) by approximately 3-fold and lowered hunger rates. Prebiotics increased plasma glucagon-like peptide 1 and peptide YY concentrations, whereas postprandial plasma glucose responses decreased after the standardized meal. The areas under the curve for plasma glucagon-like peptide 1 and breath-hydrogen excretion measured after the meal (0-60 min) were significantly correlated (r = 0.85, P = 0.007). The glucose response was inversely correlated with the breath-hydrogen excretion areas under the curve (0-180 min; r = -0.73, P = 0.02).

CONCLUSION

Prebiotic supplementation was associated with an increase in plasma gut peptide concentrations (glucagon-like peptide 1 and peptide YY), which may contribute in part to changes in appetite sensation and glucose excursion responses after a meal in healthy subjects.

beta-Glucan-enriched bread reduces energy intake and modifies plasma ghrelin and peptide YY concentrations in the short term

Dietary fibre consumption may help to control appetite and to reduce calorie intake. Underlying molecular mechanisms were not fully investigated. The aim of this study was to evaluate the effect of barley beta-glucans on short-term appetite and on satiety-related hormones in healthy subjects. Fourteen volunteers were selected and randomly assigned to have isocaloric breakfasts including a 3% beta-glucan-enriched bread (betaGB) or a control bread (CB). Post-breakfast individual self-records of appetite ratings and measure of calorie intake at an ad libitum lunch as well as measure of blood glucose, insulin, ghrelin and PYY concentrations, were performed. betaGB determined a significant higher reduction of hunger and increase of fullness and satiety than CB. Accordingly, a 19% reduction of energy intake at lunch subsequent to betaGB consumption compared to CB, was recorded. A 23% lower AUC(60-180) of plasma ghrelin and a 16% higher total AUC of PYY response after betaGB than CB consumption, independent from insulin response, was found. Glucose response was also blunted by betaGB vs CB. Barley beta-glucans were able to control appetite in the short term by modulating sensations and reducing energy intake. Data suggested for the first time that satiety effect of beta-glucans are mediated by ghrelin and PYY.

Changes in infants faecal characteristics and microbiota by inulin supplementation

The effects of inulin on the microbial composition and faecal characteristics in 36 healthy, formula-fed infants (average age 7.7 months) given 3 different daily dosages of native inulin (0.75 g/day, 1.00 g/day, and 1.25 g/day) were studied. At all levels of inulin consumption, a significant (p<0.05) reduction of potential pathogenic microorganisms such as clostridia was found. An intake of 1.25 g/day of inulin caused a significant (p<0.05) increase of Bifidobacterium spp. as well as a significant (p<0.05) decline in Gram-positive cocci and coliform bacteria. Inulin consumption resulted in a significant (p<0.05) decrease in faecal pH value and changes in faecal weight, faecal texture and colour, indicating improvement in healthy bile production and bacterial fermentation. It is concluded that inulin consumption in formula-fed infants after weaning positively affected the microbial composition of faeces and faecal properties.

Gut microbiota and its possible relationship with obesity

Obesity results from alterations in the body's regulation of energy intake, expenditure, and storage. Recent evidence, primarily from investigations in animal models, suggests that the gut microbiota affects nutrient acquisition and energy regulation. Its composition has also been shown to differ in lean vs obese animals and humans. In this article, we review the published evidence supporting the potential role of the gut microbiota in the development of obesity and explore the role that modifying the gut microbiota may play in its future treatment. Evidence suggests that the metabolic activities of the gut microbiota facilitate the extraction of calories from ingested dietary substances and help to store these calories in host adipose tissue for later use. Furthermore, the gut bacterial flora of obese mice and humans include fewer Bacteroidetes and correspondingly more Firmicutes than that of their lean counterparts, suggesting that differences in caloric extraction of ingested food substances may be due to the composition of the gut microbiota. Bacterial lipopolysaccharide derived from the intestinal microbiota may act as a triggering factor linking inflammation to high-fat diet-induced metabolic syndrome. Interactions among microorganisms in the gut appear to have an important role in host energy homeostasis, with hydrogen-oxidizing methanogens enhancing the metabolism of fermentative bacteria. Existing evidence warrants further investigation of the microbial ecology of the human gut and points to modification of the gut microbiota as one means to treat people who are over-weight or obese.

Modulation of glucagon-like peptide 1 and energy metabolism by inulin and oligofructose: experimental data

Inulin-type fructans have been tested for their capacity to modulate lipid and glucose metabolism in several animal models. Oligofructose (OFS) decreases food intake, fat mass development, and hepatic steatosis in normal and in obese rats; moreover, it exerts an antidiabetic effect in streptozotocin-treated rats and high-fat-fed mice. In most cases, the beneficial effects of OFS are linked to an increase of glucagon-like peptide-1 (GLP-1) level in the portal vein and of GLP-1 and proglucagon mRNA, its precursor, in the proximal colon. In this organ, OFS increases the number of GLP-1-positive L cells by promoting factors (Neurogenin 3 and NeuroD) involved in the differentiation of stem cells into L cells. The chronic administration of GLP-1 receptor antagonist exendin 9-39 totally prevents the beneficial effects of OFS (improved glucose tolerance, fasting blood glucose, glucose-stimulated insulin secretion, insulin-sensitive hepatic glucose production, and reduced body weight gain). Furthermore GLP-1 receptor knockout mice are completely insensitive to the antidiabetic actions of OFS. These findings highlight the potential interest of enhancing endogenous GLP-1 secretion by inulin-type fructans for the prevention/treatment of obesity and type 2 diabetes. Moreover, OFS is also able to modulate other gastrointestinal peptides (such as PYY and ghrelin) that could be involved in the control of food intake. Several studies in humans already support interest in OFS in the control of satiety, triglyceridemia, or steatohepatitis. The link with gut peptides production in humans remains to be proven.

Gut microflora as a target for energy and metabolic homeostasis

PURPOSE OF REVIEW

Gut microbiota plays an important role in health and disease, but this ecosystem remains incompletely characterized and shows a wide diversity. This review discusses new findings that may explain how gut microbiota can be involved in the control of energy and metabolic homeostasis.

RECENT FINDINGS

Over the past 5 years studies have highlighted some key aspects of the mammalian host-gut microbial relationship. Gut microbiota could now be considered a 'microbial organ' placed within a host organ. Recent data suggest that the modulation of gut microbiota affects host metabolism and has an impact on energy storage. Several mechanisms are proposed that link events occurring in the colon and the regulation of energy metabolism.

SUMMARY

Gut microflora may play an even more important role in maintaining human health than previously thought. The literature provides new evidence that the increased prevalence of obesity and type 2 diabetes cannot be attributed solely to changes in the human genome, nutritional habits, or reduction of physical activity in our daily lives. One must also consider this important new environmental factor, namely gut microbiota. Scientists may take into consideration a key question: could we manipulate the microbiotic environment to treat or prevent obesity and type 2 diabetes? This opens up a new area in nutrition research.

Diet, nutrition, and bone health

Osteoporosis is a debilitating disease that affects many older people. Fragility fractures are the hallmark of osteoporosis. Although nutrition is only 1 of many factors that influence bone mass and fragility fractures, there is an urgent need to develop and implement nutritional approaches and policies for the prevention and treatment of osteoporosis that could, with time, offer a foundation for population-based preventive strategies. However, to develop efficient and precocious strategies in the prevention of osteoporosis, it is important to determine which modifiable factors, especially nutritional factors, are able to improve bone health throughout life. There are potentially numerous nutrients and dietary components that can influence bone health, and these range from the macronutrients to micronutrients as well as bioactive food ingredients. The evidence-base to support the role of nutrients and food components in bone health ranges from very firm to scant, depending on the nutrient/component. This article initially overviews osteoporosis, including its definition, etiology, and incidence, and then provides some information on possible dietary strategies for optimizing bone health and preventing osteoporosis. The potential benefits of calcium, vitamin D, vitamin K(1), phytoestrogens, and nondigestible oligosaccharides are briefly discussed, with particular emphasis on the evidence base for their benefits to bone. It also briefly considers some of the recent findings that highlight the importance of some dietary factors for bone health in childhood and adolescence.

Effect of prebiotic supplementation and calcium intake on body mass index

OBJECTIVE

To assess the effects of a prebiotic supplement and usual calcium intake on body composition changes during pubertal growth.

STUDY DESIGN

We measured anthropometry and body fat with dual-energy X-ray absorptiometry in 97 young adolescents who were randomized to receive either a daily prebiotic supplement or maltodextrin (control) for 1 year.

RESULTS

Subjects who received the prebiotic supplement had a smaller increase in body mass index (BMI) compared with the control group (BMI difference 0.52 +/- 0.16 kg/m2, P = .016), BMI Z-score (difference 0.13 +/- 0.06, P = .048) and total fat mass (difference 0.84 +/- 0.36 kg, P = .022). The prebiotic group maintained their baseline BMI Z-score (0.03 +/- 0.01, paired t test, P = .30), although BMI Z-score increased significantly in the control group (0.13 +/- 0.03, P < .001). In considering subjects whose usual calcium intake was > or = 700 mg/d, those who received the prebiotic supplement had a relative change in BMI that was 0.82 kg/m2 less than control subjects (P < .01), and BMI Z-score that was 0.20 less than control subjects (P = .003). Differences tended to be maintained 1 year after supplementation was stopped.

CONCLUSION

Prebiotic supplementation and avoidance of a low calcium intake can have significant effects in modulating BMI and other body composition changes during puberty.

Dietary non-digestible carbohydrates promote L-cell differentiation in the proximal colon of rats

One of the challenges in type 2 diabetes treatment is to ensure pancreas functionality with gut peptides such as glucagon-like peptide-1 (GLP-1). We have recently shown that the endogenous GLP-1 production is promoted by dietary non-digestible carbohydrates (oligofructose), the higher GLP-1 secretion could participate in the control of obesity and associated disorders. This experimental study was designed to highlight the mechanisms of endogenous increase of GLP-1 following non-digestible carbohydrate feeding. Male Wistar rats were fed a standard diet (70.4 g/100 g total carbohydrates; controls) or the same diet supplemented with oligofructose (10 g/100 g diet) for 4 weeks. GLP-1-producing L-cells of the colon were quantified by immunohistochemistry. GLP-1 was quantified by ELISA, and proglucagon, neurogenin 3 and NeuroD mRNA were measured in the colon by quantitative RT-PCR. The number of GLP-1-expressing cells was doubled in the proximal colon of oligofructose-treated rats, a phenomenon correlated with the increase in proglucagon mRNA and peptide content in the tissue. Moreover, oligofructose increased the number of enteroendocrine L-cells in the proximal colon by a mechanism involving up-regulation of two differentiation factors: neurogenin 3 and NeuroD. It is the first demonstration that nutrients fermented in the gut may promote L-cell differentiation in the proximal colon, a phenomenon contributing to a higher endogenous GLP-1 production. These results suggest a new mechanism by which dietary fibres may lower food intake and fat mass development.

Lupin-enriched bread increases satiety and reduces energy intake acutely

BACKGROUND

Protein and fiber may be important determinants of satiety. Lupin kernel flour is a novel food ingredient that is rich in protein and fiber.

OBJECTIVE

The objective was to investigate the effects of lupin kernel flour-enriched bread (LB) on satiety and energy intake in humans.

DESIGN

Two randomized controlled crossover trials were performed to compare the acute effects of LB with those of white bread (WB). In study 1, the subjects (n = 16) completed 4 treatments 1 wk apart: WB breakfast (as toast) and WB lunch (as sandwiches), WB breakfast and LB lunch, LB breakfast and WB lunch, and LB breakfast and LB lunch. Energy intake at all breakfast meals was matched (1655 kJ), and ad libitum energy intake at lunch, 3 h after breakfast, was measured. In study 2, the subjects (n = 17) completed 2 treatments 1 wk apart: WB breakfast and LB breakfast (each 1655 kJ). Blood samples were taken at baseline and at regular intervals for 3 h after breakfast.

RESULTS

In study 1, the LB breakfast resulted in significantly higher self-reported satiety (P < 0.001) and lower energy intake (kJ) at lunch (-488; 95% CI: -798, -178) than did the WB breakfast. The LB lunch resulted in a significantly lower within-meal energy intake (kJ) at lunch (-1028; 95% CI: -1338, -727) than did the WB lunch. In study 2, compared with the WB breakfast, the LB breakfast significantly altered the 3-h postmeal plasma ghrelin response (P = 0.04) and resulted in significantly lower mean 3-h plasma ghrelin concentrations (P = 0.009).

CONCLUSION

A novel food enriched in protein and fiber derived from lupin kernel flour significantly influences energy intake acutely.

Oligofructose promotes satiety in healthy human: a pilot study

OBJECTIVE

The administration of a fermentable dietary fibre (oligofructose) in rats increases satietogenic gut peptides and lowered spontaneous energy intake. The aim of the study was to assess the relevance of those effects of oligofructose on satiety and energy intake in humans.

DESIGN

Single-blinded, crossover, placebo-controlled design, pilot study.

SUBJECTS

Volunteers included five men and five women aged 21-39 years, BMI ranging from 18.5 to 27.4 kg/m(2), were randomly assigned as described below.

INTERVENTIONS

Subjects were included in two 2-week experimental phases during which they received either fibre (oligofructose (OFS)) or placebo (dextrine maltose (DM)); a 2-week washout period was included between crossover phases. In total, 8 g OFS or 8 g DM were ingested twice daily (16 g/day in total). Energy intake, hunger, satiety, fullness and prospective food consumption were assessed with analogue scales at the end of each experimental phase.

RESULTS

During breakfast, OFS significantly increases the satiety (P=0.04) without any difference on other sensations as compared to DM treatment periods. After lunch, no significant differences are observed between treatment period. At dinner, OFS significantly increases satiety (P=0.04), reduces hunger (P=0.04) and prospective food consumption (P=0.05). The energy intake at breakfast and lunch are significantly lower (P=0.01, 0.03, respectively) after OFS treatment than after DM treatment. Total energy intake per day is 5% lower during OFS than in DM period.

CONCLUSION

Oligofructose treatment increases satiety following breakfast and dinner, reduces hunger and prospective food consumption following dinner. This pilot study presents a rationale to propose oligofructose supplements in the management of food intake in overweight and obese patients.

Relation between colonic proglucagon expression and metabolic response to oligofructose in high fat diet-fed mice

Several data suggest that fermentable dietary fiber could play a role in the control of obesity and associated metabolic disorders. The aim of this study was to investigate the putative role of short chain fructo-oligosaccharide (OFS) - a non-digestible oligosaccharide - in mice fed a standard diet and in mice fed two distinct high fat diets inducing metabolic disorders associated to obesity. We confirmed, in mice, several effects previously shown in rats fed a standard diet enriched with OFS, namely an increase in total and empty caecum weight, a significant decrease in epididymal fat mass, and an increase in colonic and portal plasma glucagon-like peptide-1 (GLP-1), a phenomenon positively correlated with a higher colonic proglucagon mRNA level. Curiously, 4-week treatment with OFS added at the same dose induced different effects when added in the two different high fat diets. OFS decreased energy intake, body weight gain, glycemia, and epididymal fat mass only when added together with the high fat-carbohydrate free diet, in which OFS promoted colonic proglucagon expression and insulin secretion. Our results support an association between the increase in proglucagon expression in the proximal colon and OFS effects on glycemia, fat mass development, and/or body weight gain. In conclusion, dietary oligosaccharides would constitute an interesting class of dietary fibers promoting, in certain conditions, endogenous GLP-1 production, with beneficial physiological consequences. This remains to be proven in human studies.

A place for dietary fibre in the management of the metabolic syndrome

PURPOSE OF REVIEW

To control the global increase of obesity and associated-metabolic syndrome, nutritional advice remains an important objective. This review discusses factors that may explain how dietary fibre would be helpful in the management of food intake, body weight and metabolic syndrome.

RECENT FINDINGS

Dietary fibre could play a role in the management of the metabolic syndrome through its ability to control body weight evolution through its effect on satiety; to modulate glucose homeostasis/insulin sensitivity and to positively affect factors implicated in cardiovascular diseases. The relevance and the relative importance of these effects in control of metabolic syndrome remain unknown. Recent experimental data suggest that the modification of gut peptides--involved in appetite and glucose homeostasis--could constitute a 'metabolic relay' allowing specific (fermentable) dietary fibre to act on appetite and other components of the metabolic syndrome.

SUMMARY

Dietary fibre intake may modulate parameters associated with the control of the metabolic syndrome, namely food intake (and body weight), glycemia and insulinemia, blood lipids and blood pressure. The efficacy of dietary fibre differs according to their dietary sources (fruits, legumes or cereals), but also to their specific chemical structure, responsible for their physical properties (i.e. gel forming capacity) or for their fermentation capacity in the lower part of the gut. The fermentability of dietary fibre seems important to generate specific effects on satiety and glycemia through the release of gut peptides such as glucagon-like peptide-1.

Lupin kernel fibre-enriched foods beneficially modify serum lipids in men

OBJECTIVE

To examine the effect of a diet containing a novel legume food ingredient, Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre), compared to a control diet without the addition of LKFibre, on serum lipids in men.

DESIGN

Randomized crossover dietary intervention study.

SETTING

Melbourne, Australia--Free-living men.

SUBJECTS

A total of 38 healthy males between the ages of 24 and 64 y completed the intervention.

INTERVENTION

Subjects consumed an LKFibre and a control diet for 1 month each. Both diets had the same background menus with seven additional experimental foods that either contained LKFibre or did not. Depending on energy intake, the LKFibre diet was designed to contain an additional 17 to 30 g/day fibre beyond that of the control diet.

RESULTS

Compared to the control diet, the LKFibre diet reduced total cholesterol (TC) (mean+/-s.e.m.; 4.5+/-1.7%; P=0.001), low-density lipoprotein cholesterol (LDL-C) (5.4+/-2.2%; P=0.001), TC: high-density lipoprotein cholesterol (HDL-C) (3.0+/-2.0%; P=0.006) and LDL-C:HDL-C (3.8+/-2.6%; P=0.003). No effects on HDL-C, triacylglycerols, glucose or insulin were observed.

CONCLUSIONS

Addition of LKFibre to the diet provided favourable changes to some serum lipid measures in men, which, combined with its high palatability, suggest this novel ingredient may be useful in the dietary reduction of coronary heart disease risk.

Dietary fiber as a versatile food component: An industrial perspective

The continued emphasis on the importance of dietary fibers to the Western diet and the need for products with a lower calorific content is pressuring food companies to allocate more resources to the development of fiber-enriched products. The challenge to the industry is to accomplish this goal without sacrificing the organoleptic appeal of some of their core offerings. As future research details specific nutritional benefits of individual components of dietary fiber, food companies will need flexible alternatives in order to validate new 'functional' food claims and to respond rapidly to emerging trends in fiber-enriched products. These objectives will be achieved by understanding the physicochemical basis for the biotechnical functionality of fibers and by developing, and making available fibers which provide a broad spectrum of bioactive and texture modulating properties.

Position of the American Dietetic association: fat replacers

It is the position of the American Dietetic Association that the majority of fat replacers, when used in moderation by adults, can be safe and useful adjuncts to lowering the fat content of foods and may play a role in decreasing total dietary energy and fat intake. Moderate use of low-calorie, reduced-fat foods, combined with low total energy intake, could potentially promote dietary intake consistent with the objectives of Healthy People 2010 and the 2005 Dietary Guidelines for Americans . The obesity epidemic in the nation has been attributed to energy imbalance, mainly because of increased food consumption and/or sedentary lifestyle, or both. Evidence suggests that lowering total energy intake along with a reduction in total fat intake can have a substantial impact on body weight and risk of chronic diseases. Fat replacers are used to provide some or all of the functional properties of fat, while providing fewer calories than the fat being replaced, and are used in a variety of products, from baked goods to frozen desserts. Fat replacers can be effective only if they lower the total caloric content of the food and if the consumer uses these foods as part of a balanced meal plan. Consumers should not be led to believe that fat- and calorie-reduced products can be consumed in unlimited amounts. Fat replacers are most useful when they help with calorie control and when their use encourages the consumption of foods delivering important nutrients.