Differences in satiety effects of alginate- and whey protein-based foods

Simulated gastrointestinal digestion of protein alginate complexes: effects of whey protein cross-linking and the composition and degradation of alginate

Alginate and whey protein are common additives in food production improving storage stability, texture and nutritional value. Alginate forms complexes with whey protein and inhibits proteolysis by pepsin and trypsin, but the influence of alginate protein complexation on digestion is poorly understood. This study shows that whey protein cross-linking by microbial transglutaminase dramatically decreased particle size (2-fold) and viscosity of alginate protein complexes. The INFOGEST in vitro simulated gastrointestinal digestion of whey protein was increased by cross-linking (16%) and suppressed by alginate, most pronounced with high mannuronic acid and least with high guluronic acid content. Sizes of alginate whey protein particles increased during gastric digestion, whereas for cross-linked whey protein complexes the size initially increased, but returned to their initial size at the end of gastric digestion. While alginate is not degraded by human enzymes, a few gut bacteria were recently found to encode lyases and other enzymes metabolizing alginate. Alginate lyase added to the intestinal phase enhanced digestion (9%) as controlled by alginate composition and enzyme specificity. Thus we provide evidence that use of hydrocolloids and processing of protein strongly influence digestion and should be considered when using food additives.

Seaweeds as Ingredients to Lower Glycemic Potency of Cereal Foods Synergistically-A Perspective

Seaweeds are traditional food ingredients mainly in seaside regions. Modern food science and nutrition researchers have identified seaweed as a source of functional nutrients, such as dietary soluble and insoluble fibers, proteins, omega-3 fatty acids, prebiotic polysaccharides, polyphenols, and carotenoids. Owing to the rich nutrients, seaweeds and seaweed extract can be used as functional ingredients by modifying the nutrients composition to reduce the proportion of available carbohydrates, delaying the gastric emptying time and the absorption rate of glucose by increasing the digesta viscosity, and attenuating the digesting rate by blocking the activity of digestive enzymes. This review presents the concept of using seaweed as unconventional ingredients that can function synergistically to reduce the glycemic potency of cereal products.

Effect of the perception of breakfast consumption on subsequent appetite and energy intake in healthy males

Purpose

This study aimed to assess the effects of consuming a very-low-energy placebo breakfast on subsequent appetite and lunch energy intake.

Methods

Fourteen healthy males consumed water-only (WAT), very-low-energy, viscous placebo (containing water, low-calorie flavoured squash, and xanthan gum; ~ 16 kcal; PLA), and whole-food (~ 573 kcal; FOOD) breakfasts in a randomised order. Subjects were blinded to the energy content of PLA and specific study aims. Venous blood samples were collected pre-breakfast, 60- and 180-min post-breakfast to assess plasma acylated ghrelin and peptide tyrosine tyrosine concentrations. Subjective appetite was measured regularly, and energy intake was assessed at an ad libitum lunch meal 195-min post-breakfast.

Results

Lunch energy intake was lower during FOOD compared to WAT (P < 0.05), with no further differences between trials (P ≥ 0.132). Cumulative energy intake (breakfast plus lunch) was lower during PLA (1078 ± 274 kcal) and WAT (1093 ± 249 kcal), compared to FOOD (1554 ± 301 kcal; P < 0.001). Total area under the curve (AUC) for hunger, desire to eat and prospective food consumption were lower, and fullness was greater during PLA and FOOD compared to WAT (P < 0.05). AUC for hunger was lower during FOOD compared to PLA (P < 0.05). During FOOD, acylated ghrelin was suppressed compared to PLA and WAT at 60 min (P < 0.05), with no other hormonal differences between trials (P ≥ 0.071).

Conclusion

Consuming a very-low-energy placebo breakfast does not alter energy intake at lunch but may reduce cumulative energy intake across breakfast and lunch and attenuate elevations in subjective appetite associated with breakfast omission.

Trial registration

NCT04735783, 2nd February 2021, retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02727-5.

Sodium alginate and alginic acid as pharmaceutical excipients for tablet formulation: Structure-function relationship

Alginic acid and its sodium salt are well-accepted pharmaceutical excipients fulfilling several roles in the development of solid oral dosage forms. Although they have attractive advantages as safety, abundance, relatively low cost and biodegradability, these natural polysaccharides possess a high variability that may limit their use as excipients for tablet formulation. Thus, to obtain robust formulations and high-quality drug products with consistent performance a complete understanding of the structure-property relationship becomes necessary as the structure of alginates affects both, technological and biopharmaceutical properties. This review compiles the compaction studies carried out that relate the structure of alginates to their mechanical and dissolution performances. The different analytical methods used to determine the chemical composition, primary structure and molecular weight distribution, major factors affecting the behavior of alginates in direct compression, are also exposed. Finally, different strategies reported to improve the properties of alginic acid as direct compression excipient are discussed.

Food texture influences on satiety: systematic review and meta-analysis

Obesity is one of the leading causes of preventable deaths. Development of satiety-enhancing foods is considered as a promising strategy to reduce food intake and promote weight management. Food texture may influence satiety through differences in appetite sensations, gastrointestinal peptide release and food intake, but the degree to which it does remains unclear. Herein, we report the first systematic review and meta-analyses on effects of food texture (form, viscosity, structural complexity) on satiety. Both solid and higher viscous food reduce hunger by − 4.97 mm (95% confidence interval (CI) − 8.13, − 1.80) and − 2.10 mm (95% CI − 4.38, 1.18), respectively compared to liquid and low viscous food. An effect of viscosity on fullness (95% CI 5.20 (2.43, 7.97) and a moderate effect of the form of food (95% CI − 26.19 (− 61.72, − 9.35) on food intake were noted. Due to the large variation among studies, the results should be interpreted cautiously and modestly.

Whey Protein Supplementation Compared to Collagen Increases Blood Nesfatin Concentrations and Decreases Android Fat in Overweight Women: A Randomized Double-Blind Study

Protein supplements are usually used to control body weight, however, the impact of protein quality on body fat attenuation is unknown. We investigated the effects of isocaloric isoproteic supplementation of either whey protein (WG) or hydrolysed collagen supplementation (CG) on dietary intake, adiposity and biochemical markers in overweight women. Methods: In this randomized double-blind study, 37 women, [mean ± SE, age 40.6 ± 1.7 year; BMI (kg/m²) 30.9 ± 0.6], consumed sachets containing 40 g/day of concentrated whey protein (25 g total protein, 2.4 leucine, 1.0 valine, 1.5 isoleucine, n = 17) or 38 g/day of hydrolysed collagen (26 g total protein, 1.02 leucine, 0.91 valine, 0.53 isoleucine, n = 20) in the afternoon snack. The compliance was set at >70% of the total theoretical doses. The dietary intake was evaluated by a 6-day food record questionnaire. At the beginning and after eight weeks of follow-up, body composition was evaluated by using dual-energy X-ray absorptiometry and lipid profile, insulin resistance, C-reactive protein, adiponectin, leptin and nesfastin plasma concentrations were analyzed. Results: Supplements were isocaloric and isoproteic. There were no differences in caloric intake (p = 0.103), protein (p = 0.085), carbohydrate (p = 0.797) and lipids (p = 0.109) intakes. The branched chain amino acids (BCAA) (GC: 1.8 ± 0.1 g vs. WG: 5.5 ± 0.3 g, p < 0.001) and leucine intake (CG: 0.1 ± 0.1 g vs. WG: 2.6 ± 0.1 g, p < 0.001) were higher in WG compared to CG. BMI increased in the CG (0.2 ± 1.1 kg/m², p = 0.044) but did not change in WG. WG decreased the android fat (−0.1 ± 0.3 kg, p = 0.031) and increased nesfatin concentrations (4.9 ± 3.2 ng/mL, p = 0.014) compared to CG. Conclusions: Whey protein supplementation in overweight women increased nesfatin concentrations and could promote increase of resting metabolic rate as part of body composition improvement programs compared to collagen supplementation for 8 weeks. Additionally, our findings suggest that collagen may not be an effective supplement for overweight women who are attempting to alter body composition.

Effect of supplemental whey protein timing on postprandial glycaemia in centrally obese males

Consuming whey protein before a meal may reduce postprandial glucose excursions, however, optimising timing of supplementation is important to improve its clinical utility. A total of thirteen centrally obese, insulin-resistant males (waist circumference: 121 (sem 3) cm; homeostasis model assessment for insulin resistance (HOMA-IR): 6·4 (sem 1·2)) completed four experimental conditions in a single-blind, crossover design. Participants consumed mixed-macronutrient breakfast and lunch meals on all occasions, with 20 g whey protein consumed 15 min before (PRE), alongside (DUR) or 15 min post-breakfast (POST) or omitted (CON). Capillary glucose and plasma concentrations of insulin, TAG and NEFA, in addition to subjective appetite ratings, were collected for 180 min after each meal. PRE and DUR reduced post-breakfast glucose peak by 17·0 (sem 1·9) % (P<0·001) and 9·2 (sem 2·9) % (P=0·046), respectively, compared with CON. Post-breakfast glucose AUC was lower following PRE compared with POST and CON (PRE: 982 (sem 30) v. POST: 1031 (sem 36) and CON: 1065 (sem 37) mmol/l×180 min; P≤0·042) but similar to DUR (1013 (sem 32) mmol/l×180 min; P=0·77). Insulin was lower during PRE, when compared with POST and DUR (both P≤0·042) but similar to CON. There were no between-condition differences in measures of postprandial lipaemia or appetite, and no effect of condition post-lunch. Consumption of whey protein as a preload or alongside a mixed-macronutrient breakfast reduces postprandial glucose excursions in centrally obese, insulin-resistant males. Whey consumed as a preload has superior glycaemic-lowering effects. Supplementation at breakfast does not alter glycaemic responses to subsequent meals.

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.

A review of the characteristics of dietary fibers relevant to appetite and energy intake outcomes in human intervention trials

Background: Many intervention studies have tested the effect of dietary fibers (DFs) on appetite-related outcomes, with inconsistent results. However, DFs comprise a wide range of compounds with diverse properties, and the specific contribution of these to appetite control is not well characterized.Objective: The influence of specific DF characteristics [i.e., viscosity, gel-forming capacity, fermentability, or molecular weight (MW)] on appetite-related outcomes was assessed in healthy humans.Design: Controlled human intervention trials that tested the effects of well-characterized DFs on appetite ratings or energy intake were identified from a systematic search of literature. Studies were included only if they reported 1) DF name and origin and 2) data on viscosity, gelling properties, fermentability, or MW of the DF materials or DF-containing matrixes.Results: A high proportion of the potentially relevant literature was excluded because of lack of adequate DF characterization. In total, 49 articles that met these criteria were identified, which reported 90 comparisons of various DFs in foods, beverages, or supplements in acute or sustained-exposure trials. In 51 of the 90 comparisons, the DF-containing material of interest was efficacious for ≥1 appetite-related outcome. Reported differences in material viscosity, MW, or fermentability did not clearly correspond to differences in efficacy, whereas gel-forming DF sources were consistently efficacious (but with very few comparisons).Conclusions: The overall inconsistent relations of DF properties with respect to efficacy may reflect variation in measurement methodology, nature of the DF preparation and matrix, and study designs. Methods of DF characterization, incorporation, and study design are too inconsistent to allow generalized conclusions about the effects of DF properties on appetite and preclude the development of reliable, predictive, structure-function relations. Improved standards for characterization and reporting of DF sources and DF-containing materials are strongly recommended for future studies on the effects of DF on human physiology. This trial was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42015015336.

A role for whey-derived lactoferrin and immunoglobulins in the attenuation of obesity-related inflammation and disease

Obesity is a strong predictive factor in the development of chronic disease and has now superseded undernutrition as a major public health issue. Chronic inflammation is one mechanism thought to link excess body weight with disease. Increasingly, the gut and its extensive population of commensal microflora are recognized as playing an important role in the development of obesity-related chronic inflammation. Obesity and a high fat diet are associated with altered commensal microbial communities and increased intestinal permeability which contributes to systemic inflammation as a result of the translocation of lipopolysaccharide into the circulation and metabolic endotoxemia. Various milk proteins are showing promise in the prevention and treatment of obesity and chronic low-grade inflammation via reductions in visceral fat, neutralization of bacteria at the mucosa and reduced intestinal permeability. In this review, we focus on evidence supporting the potential antiobesogenic and anti-inflammatory effects of bovine whey-derived lactoferrin and immunoglobulins.

Marine Algae as a Potential Source for Anti-Obesity Agents

Obesity is a major epidemic that poses a worldwide threat to human health, as it is also associated with metabolic syndrome, type 2 diabetes and cardiovascular disease. Therapeutic intervention through weight loss drugs, accompanied by diet and exercise, is one of the options for the treatment and management of obesity. However, the only approved anti-obesity drug currently available in the market is orlistat, a synthetic inhibitor of pancreatic lipase. Other anti-obesity drugs are still being evaluated at different stages of clinical trials, while some have been withdrawn due to their severe adverse effects. Thus, there is a need to look for new anti-obesity agents, especially from biological sources. Marine algae, especially seaweeds are a promising source of anti-obesity agents. Four major bioactive compounds from seaweeds which have the potential as anti-obesity agents are fucoxanthin, alginates, fucoidans and phlorotannins. The anti-obesity effects of such compounds are due to several mechanisms, which include the inhibition of lipid absorption and metabolism (e.g., fucoxanthin and fucoidans), effect on satiety feeling (e.g., alginates), and inhibition of adipocyte differentiation (e.g., fucoxanthin). Further studies, especially testing bioactive compounds in long-term human trials are required before any new anti-obesity drugs based on algal products can be developed.

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.

The role of alginates in regulation of food intake and glycemia: a gastroenterological perspective

Regulation of food intake through modulation of gastrointestinal responses to ingested foods is an ever-growing component of the therapeutic approaches targeting the obesity epidemic. Alginates, viscous and gel-forming soluble fibers isolated from the cell wall of brown seaweeds and some bacteria, are recently receiving considerable attention because of their potential role in satiation, satiety, and food intake regulation in the short term. Enhancement of gastric distension, delay of gastric emptying, and attenuation of postprandial glucose responses may constitute the basis of their physiological benefits. Offering physical, chemical, sensorial, and physiological advantages over other viscous and gel-forming fibers, alginates constitute promising functional food ingredients for the food industry. Therefore, the current review explores the role of alginates in food intake and glycemic regulation, their underlying modes of action and their potential in food applications.

Looking Beyond the Terrestrial: The Potential of Seaweed Derived Bioactives to Treat Non-Communicable Diseases

Seaweeds are a large and diverse group of marine organisms that are commonly found in the maritime regions of the world. They are an excellent source of biologically active secondary metabolites and have been shown to exhibit a wide range of therapeutic properties, including anti-cancer, anti-oxidant, anti-inflammatory and anti-diabetic activities. Several Asian cultures have a strong tradition of using different varieties of seaweed extensively in cooking as well as in herbal medicines preparations. As such, seaweeds have been used to treat a wide variety of health conditions such as cancer, digestive problems, and renal disorders. Today, increasing numbers of people are adopting a "westernised lifestyle" characterised by low levels of physical exercise and excessive calorific and saturated fat intake. This has led to an increase in numbers of chronic Non-communicable diseases (NCDs) such as cancer, cardiovascular disease, and diabetes mellitus, being reported. Recently, NCDs have replaced communicable infectious diseases as the number one cause of human mortality. Current medical treatments for NCDs rely mainly on drugs that have been obtained from the terrestrial regions of the world, with the oceans and seas remaining largely an untapped reservoir for exploration. This review focuses on the potential of using seaweed derived bioactives including polysaccharides, antioxidants and fatty acids, amongst others, to treat chronic NCDs such as cancer, cardiovascular disease and diabetes mellitus.

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.

Use of viscous fibres in beverages for appetite control: a review of studies

Dietary fibres, particularly viscous fibres appear to be more effective for appetite control (reduce subjective appetite, energy intake and/or body weight). Three types of viscous fibres, pectin, alginate and cereal beta-glucan, were identified as potential satiety-enhancing ingredients. The aim of this review was to collect evidence from human intervention studies evaluating pectins, alginates and beta-glucans in beverages, liquid preloads and liquid test meals for their satiety effects. Our focused, narrative review of several satiety studies shows an overall consistent result on the effectiveness of pectin, alginate and beta-glucan for appetite control. Beverages or liquid test meals are probably the better delivery mode for these fibres, as their effect on satiety is affected by their physico-chemical properties. Most, if not all, of these reviewed studies gave little or no consideration to the potential effects of common food processing (e.g. pasteurisation, ultra-high temperature process) on the physico-chemical properties of these fibre-containing beverages. This is one of the research gaps we have identified warranting further work, which is likely to be of significance from the industry and consumer perspective.

Effect of training on the reliability of satiety evaluation and use of trained panellists to determine the satiety effect of dietary fibre: a randomised controlled trial

Background

The assessment of satiety effects on foods is commonly performed by untrained volunteers marking their perceived hunger or fullness on line scales, marked with pre-set descriptors. The lack of reproducibility of satiety measurement using this approach however results in the tool being unable to distinguish between foods that have small, but possibly important, differences in their satiety effects. An alternate approach is used in sensory evaluation; panellists can be trained in the correct use of the assessment line-scale and brought to consensus on the meanings of descriptors used for food quality attributes to improve the panel reliability. The effect of training on the reliability of a satiety panel has not previously been reported.

Method

In a randomised controlled parallel intervention, the effect of training in the correct use of a satiety labelled magnitude scale (LMS) was assessed versus no-training. The test-retest precision and reliability of two hour postprandial satiety evaluation after consumption of a standard breakfast was compared. The trained panel then compared the satiety effect of two breakfast meals containing either a viscous or a non-viscous dietary fibre in a crossover trial.

Results

A subgroup of the 23 panellists (n = 5) improved their test re-test precision after training. Panel satiety area under the curve, “after the training” intervention was significantly different to “before training” (p < 0.001). Reliability of the panel determined by intraclass correlation (ICC) of test and retest showed improved strength of the correlation from 0.70 pre-intervention to 0.95 post intervention. The trained “satiety expert panel” determined that a standard breakfast with 5g of viscous fibre gave significantly higher satiety than with 5g non-viscous fibre (area under curve (AUC) of 478.2, 334.4 respectively) (p ≤ 0.002).

Conclusion

Training reduced between panellist variability. The improved strength of test-retest ICC as a result of the training intervention suggests that training satiety panellists can improve the discriminating power of satiety evaluation.

Effects of two dietary fibers as part of ready-to-eat cereal (RTEC) breakfasts on perceived appetite and gut hormones in overweight women

The effects of an enzyme-hydrolyzed arabinoxylan from wheat (AXOS) versus an intact arabinoxylan from flax (FLAX) added to a ready-to-eat cereal (RTEC) on the postprandial appetitive, hormonal, and metabolic responses in overweight women (BMI 25.0–29.9 kg/m²) were evaluated. Subsequent meal energy intake was also assessed. Two randomized, double-blind, crossover design studies were completed. For trial 1, the participants consumed the following RTEC breakfast, matched for total weight and varied in energy content: low-fiber (LF, 4 g); high-fiber (HF, 15 g) as either AXOS or FLAX. For trial 2, the participants consumed LF, HF-AXOS, and HF-FLAX RTECs but also consumed another LF breakfast that was isocaloric (LF-iso) to that of the HF breakfasts. Perceived appetite and blood samples (trial 2 only) were assessed before and after breakfast. An ad libitum lunch was offered 4 h post-breakfast. No differences in postprandial appetite responses were observed among any breakfasts in either trial. The HF-AXOS and HF-FLAX led to increased postprandial GLP-1 and peptide YY (PYY) concentrations vs. LF-iso. No differences were observed in lunch meal energy intake among breakfast meals in either trial. Collectively, these data suggest that 15 g of low molecular weight fiber added to RTECs did not affect perceived appetite or subsequent energy intake despite differences in satiety hormone signaling in overweight females.

Effects of a Macro-Nutrient Preload on Type 2 Diabetic Patients

AIMS

Macro-nutrient preloads given 30 min before regular meals may improve metabolism. The aim was to investigate how type 2 diabetic patients react to a preload consisting of a blend of macro-nutrients with a low-glycemic index (Inzone Preload(®)).

METHODS

In a before-after study design, 30 subjects with type 2 diabetes mellitus (T2DM) were enrolled in a 12-week program. All subjects were given Inzone Preload (43% proteins, 29% carbohydrates, 10% lipids, and 9% fibers, 71 kcal), 30 min before each meal during 12 weeks. Fasting glucose and postprandial 2 h glucose were monitored every second week. Body weight (BW) and waist circumference were measured each month. Fasting plasma glucose, glycosylated hemoglobin, serum lipids, fasting insulin, C-reactive protein, and homeostasis model assessment were evaluated before and after the intervention. Subjective appetite was monitored using visual analogue scales after the Inzone Preload.

RESULTS

The dietary intervention significantly influenced several metabolic parameters compared to base line. Inzone Preload treatment reduced mean postprandial plasma glucose levels (12.2 ± 1.2 vs. 10.5 ± 2.0 mmol/L), HbA1c (7.4 ± 0.3 vs. 7.1 ± 0.2%), mean total cholesterol (4.8 ± 0.9 vs. 4.3 ± 0.8 mmol/L), low-density lipoprotein cholesterol (2.8 ± 0.6 vs. 2.5 ± 0.4 mmol/L), and CRP (1.5 ± 1.4 vs. 0.7 ± 0.7 mg/L). BW loss of more than 3% was seen in 13 participants (43%). Feelings of satiety were significantly higher after Inzone Preload than after habitual breakfast (p < 0.05). No significant changes in fasting blood glucose, high-density lipoprotein and total triacylglycerol, HOMA-IR, and HOMA-β were observed.

CONCLUSION

A macro-nutrient preload treatment reduces postprandial glucose, inflammatory markers, and serum lipids in patients with T2DM. Approximately half of the study group also displayed reduced BW.

L-cysteine suppresses ghrelin and reduces appetite in rodents and humans

BACKGROUND

High-protein diets promote weight loss and subsequent weight maintenance, but are difficult to adhere to. The mechanisms by which protein exerts these effects remain unclear. However, the amino acids produced by protein digestion may have a role in driving protein-induced satiety.

METHODS

We tested the effects of a range of amino acids on food intake in rodents and identified l-cysteine as the most anorexigenic. Using rodents we further studied the effect of l-cysteine on food intake, behaviour and energy expenditure. We proceeded to investigate its effect on neuronal activation in the hypothalamus and brainstem before investigating its effect on gastric emptying and gut hormone release. The effect of l-cysteine on appetite scores and gut hormone release was then investigated in humans.

RESULTS

l-Cysteine dose-dependently decreased food intake in both rats and mice following oral gavage and intraperitoneal administration. This effect did not appear to be secondary to behavioural or aversive side effects. l-Cysteine increased neuronal activation in the area postrema and delayed gastric emptying. It suppressed plasma acyl ghrelin levels and did not reduce food intake in transgenic ghrelin-overexpressing mice. Repeated l-cysteine administration decreased food intake in rats and obese mice. l-Cysteine reduced hunger and plasma acyl ghrelin levels in humans.

CONCLUSIONS

Further work is required to determine the chronic effect of l-cysteine in rodents and humans on appetite and body weight, and whether l-cysteine contributes towards protein-induced satiety.

Designing food structures for nutrition and health benefits

In addition to providing specific sensory properties (e.g., flavor or textures), there is a need to produce foods that also provide functionality within the gastrointestinal (GI) tract, over and above simple nutrition. As such, there is a need to understand the physical and chemical processes occurring in the mouth, stomach, small intestine, and large intestine, in addition to the food structure-physiology interactions. In vivo techniques and in vitro models have allowed us to study and simulate these processes, which aids us in the design of food microstructures that can provide functionality within the human body. Furthermore, it is important to be aware of the health or nutritional needs of different groups of consumers when designing food structures, to provide targeted functionality. Examples of three groups of consumers (elderly, obese, and athletes) are given to demonstrate their differing nutritional requirements and the formulation engineering approaches that can be utilized to improve the health of these individuals. Eating is a pleasurable process, but foods of the future will be required to provide much more in terms of functionality for health and nutrition.

Review: efficacy of alginate supplementation in relation to appetite regulation and metabolic risk factors: evidence from animal and human studies

This review provides a critical update on human and animal studies investigating the effect of alginate supplementation on appetite regulation, glycaemic and insulinemic responses, and lipid metabolism with discussion of the evidence on potential mechanisms, efficacy and tolerability. Dependent on vehicle applied for alginate supplementation, the majority of animal and human studies suggest that alginate consumption does suppress satiety and to some extent energy intake. Only one long-term intervention trial found effects on weight loss. In addition, alginates seem to exhibit beneficial influence on postprandial glucose absorption and insulin response in animals and humans. However, alginate supplementation was only found to have cholesterol-lowering properties in animals. Several mechanisms have been suggested for the positive effect observed, which involve delayed gastric emptying, increased viscosity of digesta and slowed nutrient absorption in the small intestine upon alginate gel formation. Despite reasonable efficacy and tolerability from the acute or short-term studies, we still realize there is a critical need for development of optimal alginate types and vehicles as well as studies on further long-term investigation on alginate supplementation in humans before inferring that it could be useful in the management of obesity and the metabolic syndrome.

Acute effect of alginate-based preload on satiety feelings, energy intake, and gastric emptying rate in healthy subjects

Viscous dietary fibers such as sodium alginate extracted from brown seaweed have received much attention lately for their potential role in energy regulation through the inhibition of energy intake and increase of satiety feelings. The aim of our study was to investigate the effect on postprandial satiety feelings, energy intake, and gastric emptying rate (GER), by the paracetamol method, of two different volumes of an alginate-based preload in normal-weight subjects. In a four-way placebo-controlled, double-blind, crossover trial, 20 subjects (age: 25.9 ± 3.4 years; BMI: 23.5 ± 1.7 kg/m(2)) were randomly assigned to receive a 3% preload concentration of either low volume (LV; 9.9 g alginate in 330 ml) or high volume (HV; 15.0 g alginate in 500 ml) alginate-based beverage, or an iso-volume placebo beverage. The preloads were ingested 30 min before a fixed breakfast and again before an ad libitum lunch. Consumption of LV-alginate preload induced a significantly lower (8.0%) energy intake than the placebo beverage (P = 0.040) at the following lunch meal, without differences in satiety feelings or paracetamol concentrations. The HV alginate significantly increased satiety feelings (P = 0.038), reduced hunger (P = 0.042) and the feeling of prospective food consumption (P = 0.027), and reduced area under the curve (iAUC) paracetamol concentrations compared to the placebo (P = 0.05). However, only a 5.5% reduction in energy intake was observed for HV alginate (P = 0.20). Although they are somewhat contradictory, our results suggest that alginate consumption does affect satiety feelings and energy intake. However, further investigation on the volume of alginate administered is needed before inferring that this fiber has a possible role in short-term energy regulation.

Dietary whey protein lessens several risk factors for metabolic diseases: a review

Obesity and type 2 diabetes mellitus (DM) have grown in prevalence around the world, and recently, related diseases have been considered epidemic. Given the high cost of treatment of obesity/DM-associated diseases, strategies such as dietary manipulation have been widely studied; among them, the whey protein diet has reached popularity because it has been suggested as a strategy for the prevention and treatment of obesity and DM in both humans and animals. Among its main actions, the following activities stand out: reduction of serum glucose in healthy individuals, impaired glucose tolerance in DM and obese patients; reduction in body weight; maintenance of muscle mass; increases in the release of anorectic hormones such as cholecystokinin, leptin, and glucagon like-peptide 1 (GLP-1); and a decrease in the orexigenic hormone ghrelin. Furthermore, studies have shown that whey protein can also lead to reductions in blood pressure, inflammation, and oxidative stress.

Possible role of milk-derived bioactive peptides in the treatment and prevention of metabolic syndrome

The growing prevalence of metabolic syndrome as well as its impact on public health has garnered increased attention in recent years. As a result, metabolic syndrome is now considered one of the world's leading public health problems. Bioactive peptides deriving from milk proteins may play an important role in the prevention and treatment of metabolic syndrome and its complications via several mechanisms, such as the satiety response, the regulation of insulinemia levels and blood pressure, the uptake of free radicals, and alteration of the lipid profile. These peptides can be incorporated into functional foods or administered via nutraceuticals to decrease the risk of obesity, atherogenesis, arterial hypertension, and type 2 diabetes. Recent findings have generated considerable scientific and commercial interest in milk-derived bioactive peptides, leading to numerous publications on the effectiveness of these substances. This review summarizes the current knowledge on bioactive peptides derived from milk proteins and examines the potential value of these peptides in the treatment and prevention of metabolic syndrome and its complications.

Dietary fibres in the regulation of appetite and food intake. Importance of viscosity

Dietary fibres have many functions in the diet, one of which may be to promote control of energy intake and reduce the risk of developing obesity. This is linked to the unique physico-chemical properties of dietary fibres which aid early signalling of satiation and prolonged or enhanced sensation of satiety. Particularly the ability of some dietary fibres to increase viscosity of intestinal contents offers numerous opportunities to affect appetite regulation. Few papers on the satiating effect of dietary fibres include information on the physico-chemical characteristics of the dietary fibres being tested, including molecular weight and viscosity. For viscosity to serve as a proxy for soluble dietary fibres it is essential to have an understanding of individual dietary fibre viscosity characteristics. The goal of this paper is to provide a brief overview on the role of dietary fibres in appetite regulation highlighting the importance of viscosity.