The role of dietary fibers in regulating appetite, an overview of mechanisms and weight consequences

Ultra-processed foods cause weight gain and increased energy intake associated with reduced chewing frequency: A randomized, open-label, crossover study

AIM

To elucidate the effects of ultra-processed foods (UPFs) on body weight and ad libitum energy intake compared with non-UPFs.

MATERIALS AND METHODS

In this randomized, open-label crossover study conducted at the University of Tokyo Hospital, overweight/obese Japanese male participants were randomly assigned (1:1) to start the study with consumption of either UPFs or non-UPFs for 1 week, followed by a 2-week washout period, before crossing over to the alternate food diet for 1 week. Individuals with diabetes, hypertension or any other medical conditions who visited a hospital regularly were excluded. The meals were designed to be matched for the total energy and macronutrient levels. The primary outcome was the difference in the body weight change between the UPF and non-UPF periods. The differences in the average daily energy intake and chewing frequency were assessed as one of the prespecified secondary outcomes.

RESULTS

Nine eligible participants were randomly assigned to start the study with either UPFs or non-UPFs. All participants completed the study. During the UPF period, participants gained 1.1 kg more weight (95% confidence interval 0.2 to 2.0; P = .021) and consumed 813.5 kcal more per day (342.4 to 1284.7; P = .0041) compared with during the non-UPF period. Regarding the chewing frequency, the number of chews per calorie was significantly lower during the UPF period (P = .016).

CONCLUSIONS

Consumption of UPFs causes significant weight gain. Medical nutritional therapy focused on reducing the consumption of UPFs could be an effective strategy for preventing obesity.

Label-free quantitative proteomic analysis of functional changes of goat milk whey proteins subject to heat treatments of ultra-high-temperature and the common low-temperature

This work investigated the functional changes in whey proteins obtained from goat milk subject to various temperature treatments. Ultra-high temperature instantaneous sterilization (UHTIS) caused less damage than the common low-temperature, whereas spray-drying treatment had the opposite effect. A total of 426 proteins were identified in UHTIS and control treatment groups, including 386 common proteins and 16 and 14 unique proteins. The UHTIS treatment upregulated 55 whey proteins while down-regulated 98. The UHTIS-treated whey proteins may upregulate three metabolic pathways but downregulate one. Overall, UHTIS only slightly impacted the composition and functions of whey proteins from goat milk compared to the common low-temperature treatments.

Strawberry (Fragaria x Ananassa) intake on human health and disease outcomes: a comprehensive literature review

Strawberries provide a number of potential health promoting phytonutrients to include phenolics, polyphenols, fiber, micronutrients and vitamins. The objective of this review is to provide a comprehensive summary of recent human studies pertaining to the intake of strawberry and strawberry phytonutrients on human health. A literature search conducted through PubMed and Cochrane databases consolidated studies focusing on the effects of strawberry intake on human health. Articles were reviewed considering pre-determined inclusion and exclusion criteria, including experimental or observational studies that focused on health outcomes, and utilized whole strawberries or freeze-dried strawberry powder (FDSP), published between 2000-2023. Of the 60 articles included in this review, 47 were clinical trials, while 13 were observational studies. A majority of these studies reported on the influence of strawberry intake on cardiometabolic outcomes. Study designs included those examining the influence of strawberry intake during the postprandial period, short-term trials randomized with a control, or a single arm intake period controlling with a low polyphenolic diet or no strawberry intake. A smaller proportion of studies included in this review examined the influence of strawberry intake on additional outcomes of aging including bone and brain health, and cancer risk. Data support that the inclusion of strawberries into the diet can have positive impacts during the postprandial period, with daily intake improving outcomes of lipid metabolism and inflammation in those at increased cardiovascular risk.

Inulin: a multifaceted ingredient in pharmaceutical sciences

Inulin, a naturally occurring polysaccharide derived from plants such as chicory root, has emerged as a significant ingredient in pharmaceutical sciences due to its diverse therapeutic and functional properties. This review explores the multifaceted applications of inulin, focusing on its chemical structure, sources, and mechanisms of action. Inulin's role as a prebiotic is highlighted, with particular emphasis on its ability to modulate gut microbiota, enhance gut health, and improve metabolic processes. The review also delves into the therapeutic applications of inulin, including its potential in managing metabolic health issues such as diabetes and lipid metabolism, as well as its immune-modulating properties and benefits in gastrointestinal health. Furthermore, the article examines the incorporation of inulin in drug formulation and delivery systems, discussing its use as a stabilizing agent and its impact on enhancing drug bioavailability. Innovative inulin-based delivery systems, such as nanoparticles and hydrogels, are explored for their potential in controlled release formulations. The efficacy of inulin is supported by a review of clinical studies, underscoring its benefits in managing conditions like diabetes, cardiovascular health, and gastrointestinal disorders. Safety profiles, regulatory aspects, and potential side effects are also addressed. This comprehensive review concludes with insights into future research directions and the challenges associated with the application of inulin in pharmaceutical sciences.

The effects of a fibre-enriched bakery product on glucose, insulin values and appetite. A pilot randomised cross-over trial

Brewers spent grain (BSG) is a valuable source of arabinoxylans with potential beneficial effects on glucose values. This pilot randomised crossover double-blind trial compared the effects of panettone, a sweet baked-product, enriched with BSG-fibre (p-rich) to unenriched panettone (p-standard) on glucose and insulin blood values and appetite scores. Ten healthy volunteers consumed each food in a random order. Blood variables and appetite scores were assessed at fasting and at different intervals after each food consumption. Glucose values were significantly higher after p-standard intake at 90-min (89.9 ± 16.1 vs 74.6 ± 19.4 mg/dL) and 120-min (81.1 ± 9.85 vs 72.1 ± 14.0 mg/dL). The areas-under-the-curve (AUCs) were lower for both glucose (p = .043) and insulin values (p = .036) with p-rich. At 240-min, satiety was higher (p = .006), and desire-to-eat lower (p = .008) with p-rich; desire-to-eat AUC was lower with p-rich too (p = .029). The integration of a small amount of BSG-derived fibre into a sweet food led to improved glycaemic control and appetite regulation.

The double burden of malnutrition in individuals: Identifying key challenges and re-thinking research focus

The 'double burden of malnutrition' is a global health challenge that increasingly affects populations in both low- and middle-income countries (LMICs). This phenomenon refers to the coexistence of undernutrition and overweight or obesity, as well as other diet-related non-communicable diseases, in the same population, household or even individual. While noteworthy progress has been made in reducing undernutrition in some parts of the world, in many of these areas, the prevalence of overweight and obesity is increasing, particularly in urban areas, resulting in greater numbers of people who were undernourished in childhood and have overweight or obesity in adulthood. This creates a complex and challenging situation for research experts and policymakers who must simultaneously address the public health burdens of undernutrition and overweight/obesity. This review identifies key challenges and limitations in the current research on the double burden of malnutrition in individuals, including the need for a more comprehensive and nuanced understanding of the drivers of malnutrition, the importance of context-specific interventions and the need for greater attention to the food environment and food systems. We advocate for the re-evaluation of research strategies and focus, with a greater emphasis on multidisciplinary and systems approaches and greater attention to the synergistic relationship between the biological, environmental, commercial and socio-economic determinants of malnutrition. Addressing these key challenges can enable us to better comprehend and tackle the multifaceted and dynamic issues of the double burden of malnutrition, particularly in individuals and work towards more effective and sustainable solutions.

In vitro and in vivo fermentation models to study the function of dietary fiber in pig nutrition

The importance of dietary fiber (DF) in animal diets is increasing with the advancement of nutritional research. DF is fermented by gut microbiota to produce metabolites, which are important in improving intestinal health. This review is a systematic review of DF in pig nutrition using in vitro and in vivo models. The fermentation characteristics of DF and the metabolic mechanisms of its metabolites were summarized in an in vitro model, and it was pointed out that SCFAs and gases are the important metabolites connecting DF, gut microbiota, and intestinal health, and they play a key role in intestinal health. At the same time, some information about host-microbe interactions could have been improved through traditional animal in vivo models, and the most direct feedback on nutrients was generated, confirming the beneficial effects of DF on sow reproductive performance, piglet intestinal health, and growing pork quality. Finally, the advantages and disadvantages of different fermentation models were compared. In future studies, it is necessary to flexibly combine in vivo and in vitro fermentation models to profoundly investigate the mechanism of DF on the organism in order to promote the development of precision nutrition tools and to provide a scientific basis for the in-depth and rational utilization of DF in animal husbandry. KEY POINTS: • The fermentation characteristics of dietary fiber in vitro models were reviewed. • Metabolic pathways of metabolites and their roles in the intestine were reviewed. • The role of dietary fiber in pigs at different stages was reviewed.

Deacetylated Konjac Glucomannan with a Slower Hydration Rate Delays Rice Digestion and Weakens Appetite Response

The physical characteristics of chyme during gastrointestinal digestion are considered to significantly affect nutrient digestion and absorption (such as glucose diffusion), which has an impact on postprandial satiety. The present study aims to analyze the hydration rate (HR) and rheological properties of deacetylated konjac glucomannan (DKGM) at different degrees and then explore their effects on rice texture, digestive properties, and the subjects' post-meal appetite. The present results show that, as the deacetylation degree (DD) of KGM increased, the intersection point of the viscoelastic modulus shifted to a high shear rate frequency, and as the swelling time of the DKGM was prolonged, its HR decreased significantly. The results of the in vitro gastrointestinal digestion tests show that the hardness and chewability of the rice in the fast-hydration group (MK1) were remarkably reduced. In contrast, the slow-hydration group (MK5) exhibited an outstanding ability to resist digestion. The kinetics of starch hydrolysis revealed that the HR of the rice in the fast-hydration group was 1.8 times faster than that of the slow-hydration group. Moreover, it was found that the subjects' appetite after the meal was highly related to the HR of the MK. Their hunger (p < 0.001), desire to eat (p < 0.001), and prospective food consumption (p < 0.001) were significantly inhibited in the slow-hydration group (MK5) compared to the control. This study explored the nutritional effects of the hydration properties derived from the DKGM, which may contribute to modifying the high glycemic index food and provide ideas for the fabrication of food with enhanced satiating capacity.

Designing healthier and more sustainable ultraprocessed foods

The food industry has been extremely successful in creating a broad range of delicious, affordable, convenient, and safe food and beverage products. However, many of these products are considered to be ultraprocessed foods (UPFs) that contain ingredients and are processed in a manner that may cause adverse health effects. This review article introduces the concept of UPFs and briefly discusses food products that fall into this category, including beverages, baked goods, snacks, confectionary, prepared meals, dressings, sauces, spreads, and processed meat and meat analogs. It then discusses correlations between consumption levels of UPFs and diet-related chronic diseases, such as obesity and diabetes. The different reasons for the proposed ability of UPFs to increase the risk of these chronic diseases are then critically assessed, including displacement of whole foods, high energy densities, missing phytochemicals, contamination with packaging chemicals, hyperpalatability, harmful additives, rapid ingestion and digestion, and toxic reaction products. Then, potential strategies to overcome the current problems with UPFs are presented, including reducing energy density, balancing nutritional profile, fortification, increasing satiety response, modulating mastication and digestion, reengineering food structure, and precision processing. The central argument is that it may be possible to reformulate and reengineer many UPFs to improve their healthiness and sustainability, although this still needs to be proved using rigorous scientific studies.

Mechanism of action of the bile acid receptor TGR5 in obesity

G protein-coupled receptors (GPCRs) are a large family of membrane protein receptors, and Takeda G protein-coupled receptor 5 (TGR5) is a member of this family. As a membrane receptor, TGR5 is widely distributed in different parts of the human body and plays a vital role in regulating metabolism, including the processes of energy consumption, weight loss and blood glucose homeostasis. Recent studies have shown that TGR5 plays an important role in glucose and lipid metabolism disorders such as fatty liver, obesity and diabetes. With the global obesity situation becoming more and more serious, a comprehensive explanation of the mechanism of TGR5 and filling the gaps in knowledge concerning clinical ligand drugs are urgently needed. In this review, we mainly explain the anti-obesity mechanism of TGR5 to promote the further study of this target, and show the electron microscope structure of TGR5 and review recent studies on TGR5 ligands to illustrate the specific binding between TGR5 receptor binding sites and ligands, which can effectively provide new ideas for ligand research and promote drug research.

Preparation of a novel expandable konjac fiber at different freezing temperatures and exploration of its digestion regulation functions

A new form of konjac fiber was successfully prepared, and it could instantaneously expand when in contact with the digestive fluid. The expanded konjac fiber could inhibit the digestion of the ingested food by competing with the substrate for digestive enzymes and space. The konjac fiber with desirable physical properties was obtained at 4 different freezing temperatures (-20 °C, -40 °C, -80 °C, and -196 °C), and the digestion regulation mechanisms of these fibers were systematically explored. The results showed that the konjac fiber prepared at -20 °C displayed an outstanding performance in delaying gastric emptying and preventing intestinal starch hydrolysis, while the fiber prepared under liquid nitrogen conditions (-196 °C) showed the weakest digestion regulation ability. However, the digestion regulation ability of this novel fiber was highly related to the food rheological property, and it exhibited a stronger interference effect on high-viscosity food. Our novel konjac fibers exhibited a great digestion regulation potential. Our findings provide valuable references for the development of dietary fiber-based satiety-enhancing functional foods.

The Importance of Dietary Fiber for Metabolic Health

Dietary fiber are non-digestible carbohydrates that are diverse, have varied functions, and are acquired by consuming plant-based foods. Some forms of fiber are digested by the gut microbiota and produce bioactive metabolites called short chain fatty acids-butyrate, acetate, and propionate. Dietary fiber is able to alter human physiology through multiple mechanisms that can result in health benefits. Unfortunately, nearly 19 out of 20 Americans do not consume the minimum recommended amount of fiber each day. This bears profound relevance to public health because at least six of the ten leading causes of death are potentially preventable or clinically improved through dietary means. Additionally, these same conditions share a common underlying pathophysiology-metabolic dysfunction. This can manifest as abdominal obesity, high blood pressure, insulin resistance, dyslipidemia, or collectively as metabolic syndrome. In this review, we will assess the evidence that consumption of dietary fiber undermines these forms of metabolic dysfunction, examine the mechanism of action for these physiologic effects, and consider the potential for dietary fiber to improve human health on a public health level by simply encouraging our patients to consume more plant-based foods in abundance and diversity.

Effects of fresh vs dried mango consumption on satiety and postprandial glucose in healthy adults

Mango is a widely favored fruit that offers high nutritional value. Mango has been studied to examine its influence on postprandial glucose, but few studies have used fresh mango compared to dried mango to measure blood glucose and satiety after consumption. Therefore, the objective of the present study was to investigate the effects of fresh versus dried mango consumption on satiety and postprandial glucose. A crossover design was implemented where 34 healthy adults (29 females and 5 males; 25.0 ± 6.0 years; BMI 23.8 ± 4.3 kg/m²) consumed either 100 kcal of fresh mango, dried mango, or white bread on three separate occasions. Following consumption, satiety was assessed every 15 min for 90 min and blood glucose was assessed every 30 min for 90 min. Consumption of fresh mango results showed a significant increase in satiety (tendency of greater fullness (P = 0.073) and less desire to eat (P < 0.05)) in participants. Fresh mango exhibited a more efficient decrease in postprandial glucose levels (P < 0.05) compared to dried mango or white bread, and fresh mango promoted a greater stability in blood glucose. Dried mango consumption also significantly lowered postprandial glucose compared to white bread (P < 0.05). These results suggest that fresh mango consumption may be beneficial in improving satiety responses and postprandial glucose control when compared to its dried alternative or white bread. The results of the study may help guide individuals who are overweight or obese and/or have type 2 diabetes by altering their food choices that ultimately could improve their health. ClinicalTrials.gov Identifier: NCT03956602.

Effects of Physical Properties of Konjac Glucomannan on Appetite Response of Rats

Dietary fiber has been widely used in designing foods with a high satiating capacity, as the use of satiety-enhancing food is considered to be a promising strategy for combating obesity and the overweight condition. In the present study, partially degraded konjac glucomannan (DKGM) diets with different water-holding capacities, swelling capacities, and viscosities were used to feed rats to investigate the effects of the fiber's physical properties in regulating the appetite response of the animals. The results showed that the mass and water content of the gastrointestinal chyme increased as the diet's physical properties were enhanced by the DKGM, which increased the stomach distention of the rats and promoted satiation. Besides, the hydrated DKGM elevated the chyme's viscosity, and the retention time of the digesta in the small intestine was prolonged significantly, which resulted in an increased concentration of cholecystokinin-8, glucagon-like peptide 1, and peptide tyrosine-tyrosine in the plasma, thus helping to maintain the satiety of rats. Furthermore, the results of the behavioral satiety sequence and meal pattern analysis showed that DKGM in the diets is more likely to reduce the food intake of rats by enhancing satiety rather than satiation, and will finally inhibit excessive weight gain. In conclusion, the physical properties of dietary fiber are highly related to the appetite response, which is a powerful tool in designing food with a high satiating capacity.