Dietary starch type affects body weight and glycemic control in freely fed but not energy-restricted obese rats

Metabolic Dysfunction-Associated Steatotic Liver Disease: From Pathogenesis to Current Therapeutic Options

The epidemiological burden of liver steatosis associated with metabolic diseases is continuously growing worldwide and in all age classes. This condition generates possible progression of liver damage (i.e., inflammation, fibrosis, cirrhosis, hepatocellular carcinoma) but also independently increases the risk of cardio-metabolic diseases and cancer. In recent years, the terminological evolution from "nonalcoholic fatty liver disease" (NAFLD) to "metabolic dysfunction-associated fatty liver disease" (MAFLD) and, finally, "metabolic dysfunction-associated steatotic liver disease" (MASLD) has been paralleled by increased knowledge of mechanisms linking local (i.e., hepatic) and systemic pathogenic pathways. As a consequence, the need for an appropriate classification of individual phenotypes has been oriented to the investigation of innovative therapeutic tools. Besides the well-known role for lifestyle change, a number of pharmacological approaches have been explored, ranging from antidiabetic drugs to agonists acting on the gut-liver axis and at a systemic level (mainly farnesoid X receptor (FXR) agonists, PPAR agonists, thyroid hormone receptor agonists), anti-fibrotic and anti-inflammatory agents. The intrinsically complex pathophysiological history of MASLD makes the selection of a single effective treatment a major challenge, so far. In this evolving scenario, the cooperation between different stakeholders (including subjects at risk, health professionals, and pharmaceutical industries) could significantly improve the management of disease and the implementation of primary and secondary prevention measures. The high healthcare burden associated with MASLD makes the search for new, effective, and safe drugs a major pressing need, together with an accurate characterization of individual phenotypes. Recent and promising advances indicate that we may soon enter the era of precise and personalized therapy for MASLD/MASH.

The Beneficial Effects of Dietary Interventions on Gut Microbiota-An Up-to-Date Critical Review and Future Perspectives

Different dietary interventions, especially intermittent fasting, are widely used and promoted by physicians; these regimens have been studied lately for their impact on the gut microbiota composition/function and, consequently, on the general physiopathological processes of the host. Studies are showing that dietary components modulate the microbiota, and, at the same time, the host metabolism is deeply influenced by the different products resulting from nutrient transformation in the microbiota compartment. This reciprocal relationship can potentially influence even drug metabolism for chronic drug regimens, significantly impacting human health/disease. Recently, the influence of various dietary restrictions on the gut microbiota and the differences between the effects were investigated. In this review, we explored the current knowledge of different dietary restrictions on animal and human gut microbiota and the impact of these changes on human health.

Pharmacotherapies of NAFLD: updated opportunities based on metabolic intervention

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease that is becoming increasingly prevalent, and it ranges from simple steatosis to cirrhosis. However, there is still a lack of pharmacotherapeutic strategies approved by the Food and Drug Administration, which results in a higher risk of death related to carcinoma and cardiovascular complications. Of note, it is well established that the pathogenesis of NAFLD is tightly associated with whole metabolic dysfunction. Thus, targeting interconnected metabolic conditions could present promising benefits to NAFLD, according to a number of clinical studies. Here, we summarize the metabolic characteristics of the development of NAFLD, including glucose metabolism, lipid metabolism and intestinal metabolism, and provide insight into pharmacological targets. In addition, we present updates on the progresses in the development of pharmacotherapeutic strategies based on metabolic intervention globally, which could lead to new opportunities for NAFLD drug development.

Effects of Different Dietary Starch Sources and Digestible Lysine Levels on Carcass Traits, Serum Metabolites, Liver Lipid and Breast Muscle Protein Metabolism in Broiler Chickens

This study investigated the effects of digestible lysine (dLys) in different dietary starch sources on liver lipid metabolism and breast muscle protein metabolism in broiler chickens. The experimental design was a 3 × 3 two-factor completely randomized design. A total of 702 one-day-old male Arbor Acres Plus broilers were randomly divided into nine treatments of six replicate cages with thirteen birds each. The treatments consisted of three different starch sources (corn, cassava and waxy corn) with three different dLys levels (1.08%, 1.20% and 1.32%). The trial lasted from 1 to 21 days. Carcass traits, serum metabolites, breast muscle protein and liver lipid metabolism were evaluated. A significant interaction effect (p < 0.05) for dietary starch sources and dLys levels was noted in the percentage of abdominal fat and gene expression related to breast muscle protein metabolism throughout the experimental period. The waxy corn starch diet and a 1.08% dLys level in the diet increased both the percentage of abdominal fat (p < 0.01) and blood total cholesterol (p < 0.05) in the broilers. The waxy corn starch diet significantly upregulated the mRNA expressions of Eif4E, AMPK, FABP1, ACC and CPT1 (p < 0.05). The 1.32% dLys level significantly upregulated the mRNA expressions of mTOR, S6K1, Eif4E, AMPK and PPARα (p < 0.05) and significantly downregulated the mRNA expressions of MuRF and Atrogin-1 (p < 0.05). In summary, the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. Our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits.

The Effect of Buckwheat Resistant Starch on Intestinal Physiological Function

Resistant starch appears to have promising effects on hypertension, cardiovascular and enteric illness. The influence of resistant starch on intestinal physiological function has drawn great attention. In this study, we first analyzed the physicochemical characteristics, including the crystalline properties, amylose content, and anti-digestibility among different types of buckwheat-resistant starch. The influence of resistant starch on the physiological functions of the mouse intestinal system, contained defecation, and intestinal microbes were also evaluated. The results showed that the crystalline mold of buckwheat-resistant starch changed from A to B + V after acid hydrolysis treatment (AHT) and autoclaving enzymatic debranching treatment (AEDT). The amylose content in AEDT was higher than in AHT and raw buckwheat. Moreover, the anti-digestibility of AEDT was also stronger than that in AHT and raw buckwheat. The buckwheat-resistant starch can promote bowel intestinal tract movement. The quantity of intestinal microbe was regulated by buckwheat-resistant starch. Our research demonstrates an effective preparation method for improving the quality of buckwheat-resistant starch and found that buckwheat-resistant starch has the role of adjusting the distribution of the intestinal flora and maintaining the health of the body.

A low chromium diet increases body fat, energy intake and circulating triglycerides and insulin in male and female rats fed a moderately high-fat, high-sucrose diet from peripuberty to young adult age

Trivalent chromium (Cr) may function to potentiate the action of insulin, but the effects of chromium intakes on metabolic parameters are unclear. Cr is listed as a potentially beneficial element for rodents based on studies that show feeding low quantities affect glucose metabolism. Cr is recommended at 1 mg per kg in rodent diets. This study examined the effects of different levels of dietary Cr on body weight, body composition, energy intake, food efficiency and metabolic parameters of lipid and glucose metabolism in male and female rats when fed from peripuberty to young adult age in the background of a moderately high-fat, high-sucrose diet. Sprague-Dawley CD rats (n = 10 males and 10 females/group) at 35 days of age were assigned by weight to the low (LCr, 0.33 ± 0.06 mg/kg), normal (NCr, 1.20 ± 0.11 mg/kg) or high (HCr, 9.15 ± 0.65 mg/kg) Cr diets. Diets were fed ad libitum for 12 weeks (83 days). At baseline, body weights and composition were similar (p≥0.05) among diet groups. Compared to the NCr group, the LCr group weighed more (p<0.01) and consumed more energy (food) from Day 56 onwards, but food efficiency was unaffected. Following an oral glucose challenge (Day 77), dietary chromium levels did not affect plasma glucose, but fasting plasma insulin and insulin at 30 and 60 min after dosing were higher in the LCr group compared to the NCr group. At the end of the study, whole-body fat, accrued body fat from baseline and fasting serum triglycerides were higher in the LCr group compared to the NCr group. Effects were similar in both sexes and not observed in the HCr group. These data show that low dietary Cr affects metabolic parameters common in chronic diseases underscoring the need for clinical trials to define the nutritional and/or pharmacological effects of Cr.

Octenyl Succinic Anhydride-Modified Starch Attenuates Body Weight Gain and Changes Intestinal Environment of High-Fat Diet-Fed Mice

Effects of octenylsuccinate (OS) starch on body composition and intestinal environment in high-fat diet-fed mice were investigated. C57BL/6J mice were treated with a regular-fat (RF) diet, a high-fat (HF) diet, or a high-fat diet supplemented with OS starch (HFOSS). Fecal short-chain fatty acids (SCFAs) were quantified using gas chromatography, and the fecal microbiota profile was analyzed by 16S rDNA sequencing. One-way ANOVA and metastats analysis were performed for statistical analysis. After 22 weeks of feeding, mice in the HFOSS group had significantly lower body weight, body fat, liver weight, and cumulative food intake than those in the HF group but higher than that of the RF group. Fecal total SCFA, acetic, propionic, and butyric acid concentrations were significantly higher in the HFOSS group than that in the HF and RF groups. OS starch intervention increased the relative abundance of Parabacteroides, Alistipes, and Ruminiclostridium_5 and decreased that of Tyzzerella, Oscillibacter, Desulfovibrio, and Anaerotruncus compared with the RF and HF groups. The relative abundance of Lachnospiraceae_UCG-006 in the HFOSS group was lower than that in the HF group but higher than that in the RF group. In conclusion, OS starch prevents fat accumulation in high-fat diet-fed mice and might provide potential health benefits due to its fermentability in the gut and its ability to regulate gut microbial community structure.

Gut microbes and food reward: From the gut to the brain

Inappropriate food intake behavior is one of the main drivers for fat mass development leading to obesity. Importantly the gut microbiota-mediated signals have emerged as key actors regulating food intake acting mainly on the hypothalamus, and thereby controlling hunger or satiety/satiation feelings. However, food intake is also controlled by the hedonic and reward systems leading to food intake based on pleasure (i.e., non-homeostatic control of food intake). This review focus on both the homeostatic and the non-homeostatic controls of food intake and the implication of the gut microbiota on the control of these systems. The gut-brain axis is involved in the communications between the gut microbes and the brain to modulate host food intake behaviors through systemic and nervous pathways. Therefore, here we describe several mediators of the gut-brain axis including gastrointestinal hormones, neurotransmitters, bioactive lipids as well as bacterial metabolites and compounds. The modulation of gut-brain axis by gut microbes is deeply addressed in the context of host food intake with a specific focus on hedonic feeding. Finally, we also discuss possible gut microbiota-based therapeutic approaches that could lead to potential clinical applications to restore food reward alterations. Therapeutic applications to tackle these dysregulations is of utmost importance since most of the available solutions to treat obesity present low success rate.

High-Amylose Corn Starch Regulated Gut Microbiota and Serum Bile Acids in High-Fat Diet-Induced Obese Mice

Simple Summary

High-amylose corn starch, as a kind of resistant starch, could profoundly regulate the gut microbiota and exert anti-obesity properties. Since the gut microbiota was found to improve metabolic health by altering circulating bile acids, therefore, here we investigated the association between the gut microbiota and serum bile acids in high fat diet induced obese mice fed with high-amylose corn starch. We found high-amylose corn starch could modulate the gut microbiota composition and partially restore the alternations in circulating bile acid profiles in obese mice. These influences on gut microbiota and circulating bile acids could be the underlying mechanisms of anti-obesity activity of high-amylose corn starch.

Abstract

High-amylose corn starch is well known for its anti-obesity activity, which is mainly based on the regulatory effects on gut microbiota. Recently, the gut microbiota has been reported to improve metabolic health by altering circulating bile acids. Therefore, in this study, the influence of high-amylose corn starch (HACS) on intestinal microbiota composition and serum bile acids was explored in mice fed with a high fat diet (HFD). The results demonstrated HACS treatment reduced HFD-induced body weight gain, hepatic lipid accumulation, and adipocyte hypertrophy as well as improved blood lipid profiles. Moreover, HACS also greatly impacted the gut microbiota with increased Firmicutes and decreased Bacteroidetes relative abundance being observed. Furthermore, compared to ND-fed mice, the mice with HFD feeding exhibited more obvious changes in serum bile acids profiles than the HFD-fed mice with the HACS intervention, showing HACS might restore HFD-induced alterations to bile acid composition in blood. In summary, our results suggested that the underlying mechanisms of anti-obesity activity of HACS may involve its regulatory effects on gut microbiota and circulating bile acids.

Prebiotic potential of enzymatically prepared resistant starch in reshaping gut microbiota and their respond to body physiology

The increase in consumer demand for high-quality food products has led to growth in the use of new technologies and ingredients. Resistant starch (RS) is a recently recognised source of fibre and has received much attention for its potential health benefits and functional properties. However, knowledge about the fate of RS in modulating complex intestinal communities, the microbial members involved in its degradation, enhancement of microbial metabolites, and its functional role in body physiology is still limited. For this purpose, the current study was designed to ratify the physiological and functional health benefits of enzymatically prepared resistant starch (EM-RSIII) from maize flour. To approve the beneficial health effects as prebiotic, EM-RSIII was supplemented in rat diets. After 21 days of the experiment, EM-RSIII fed rats showed a significant reduction in body weight gain, fecal pH, glycemic response, serum lipid profile, insulin level and reshaping gut microbiota, and enhancing short-chain fatty acid compared to control. The count of butyrate-producing and starch utilizing bacteria, such as Lactobacillus, Enterococcus, and Pediococcus genus in rat’s gut, elevated after the consumption of medium and high doses of EM-RSIII, while the E. coli completely suppressed in high EM-RSIII fed rats. Short-chain fatty acids precisely increased in feces of EM-RSIII feed rats. Correlation analysis demonstrated that the effect of butyrate on functional and physiological alteration on the body had been investigated during the current study. Conclusively, the present study demonstrated the unprecedented effect of utilising EM-RSIII as a diet on body physiology and redesigning gut microorganisms.

Gut microbiome and health: mechanistic insights

The gut microbiota is now considered as one of the key elements contributing to the regulation of host health. Virtually all our body sites are colonised by microbes suggesting different types of crosstalk with our organs. Because of the development of molecular tools and techniques (ie, metagenomic, metabolomic, lipidomic, metatranscriptomic), the complex interactions occurring between the host and the different microorganisms are progressively being deciphered. Nowadays, gut microbiota deviations are linked with many diseases including obesity, type 2 diabetes, hepatic steatosis, intestinal bowel diseases (IBDs) and several types of cancer. Thus, suggesting that various pathways involved in immunity, energy, lipid and glucose metabolism are affected.In this review, specific attention is given to provide a critical evaluation of the current understanding in this field. Numerous molecular mechanisms explaining how gut bacteria might be causally linked with the protection or the onset of diseases are discussed. We examine well-established metabolites (ie, short-chain fatty acids, bile acids, trimethylamine N-oxide) and extend this to more recently identified molecular actors (ie, endocannabinoids, bioactive lipids, phenolic-derived compounds, advanced glycation end products and enterosynes) and their specific receptors such as peroxisome proliferator-activated receptor alpha (PPARα) and gamma (PPARγ), aryl hydrocarbon receptor (AhR), and G protein-coupled receptors (ie, GPR41, GPR43, GPR119, Takeda G protein-coupled receptor 5).Altogether, understanding the complexity and the molecular aspects linking gut microbes to health will help to set the basis for novel therapies that are already being developed.

Gut microbiome and health: mechanistic insights

The gut microbiota is now considered as one of the key elements contributing to the regulation of host health. Virtually all our body sites are colonised by microbes suggesting different types of crosstalk with our organs. Because of the development of molecular tools and techniques (ie, metagenomic, metabolomic, lipidomic, metatranscriptomic), the complex interactions occurring between the host and the different microorganisms are progressively being deciphered. Nowadays, gut microbiota deviations are linked with many diseases including obesity, type 2 diabetes, hepatic steatosis, intestinal bowel diseases (IBDs) and several types of cancer. Thus, suggesting that various pathways involved in immunity, energy, lipid and glucose metabolism are affected.In this review, specific attention is given to provide a critical evaluation of the current understanding in this field. Numerous molecular mechanisms explaining how gut bacteria might be causally linked with the protection or the onset of diseases are discussed. We examine well-established metabolites (ie, short-chain fatty acids, bile acids, trimethylamine N-oxide) and extend this to more recently identified molecular actors (ie, endocannabinoids, bioactive lipids, phenolic-derived compounds, advanced glycation end products and enterosynes) and their specific receptors such as peroxisome proliferator-activated receptor alpha (PPARα) and gamma (PPARγ), aryl hydrocarbon receptor (AhR), and G protein-coupled receptors (ie, GPR41, GPR43, GPR119, Takeda G protein-coupled receptor 5).Altogether, understanding the complexity and the molecular aspects linking gut microbes to health will help to set the basis for novel therapies that are already being developed.

Green banana flour supplementation improves obesity-associated systemic inflammation and regulates gut microbiota profile in mice fed high-fat diets

This study evaluated the effect of green banana flour (GBF) consumption on obesity-related conditions in mice fed high-fat diets. GBF was prepared using stage 1 green banana pulp, which was dehydrated and milled. Mice were fed a control diet (n = 20; 10% of energy from lipids) or a high-fat diet (n = 20; 50% of energy from lipids). After 10 weeks, mice were divided into 4 groups based on feed: standard chow (SC; n = 10), standard with 15% GBF (SB; n = 10), high-fat diet (HF; n = 10) and high-fat diet with 15% GBF (HFB; n = 10) for 4 weeks. HFB exhibited lower gains in body weight (-21%; p < 0.01) and in all fat pads (p < 0.01) compared with the HF group. SC, SB, and HFB showed smaller retroperitoneal white adipose tissue diameters (p < 0.001). SB and HFB-treated mice showed lower levels of leptin, IL-6, and TNF-α compared with the SC and HF groups (p < 0.01). In the GBF-fed groups, there was a reduction in the abundance of Firmicutes (SB: -22%; HFB: -23%) and an increase in Bacteroidetes (SB: +25%; HFB: +29%) compared with their counterparts. We demonstrated that GBF consumption attenuated inflammation and improved metabolic status, adipose tissue remodeling, and the gut microbiota profile of obese mice. Novelty: Green banana flour (GBF) consumption, rich in resistant starch, regulates body weight in mice fed high-fat diets. GBF consumption improves fat pad distribution in mice fed high-fat diets. GBF improves obesity-associated systemic inflammation and regulates gut microbiota profile in mice fed high-fat diets.

Potential Health Benefits of Whole Grains: Modulation of Mitochondrial Biogenesis and Energy Metabolism

Mitochondria play an essential role in maintaining cellular metabolic homeostasis. However, its dysfunction will cause different pathophysiological consequences. A specific mechanism of action has been developed by cells to adapt to changes in physiological conditions or in response to different stimuli, by meditating mitochondrial number, structure, and energy metabolism. Whole grains are considered healthier than refined grains for their higher amounts of bioactive components, with proven multiple health benefits. The modulation of an appropriate mitochondrial function contributes to the bioactive-component-based health improvements. Thus, this review aims to represent current studies that identify the impact of natural bioactive components in whole grains against metabolic disorders by modulating mitochondrial biogenesis and energy metabolism. It seems most attractive to aim nutritional intervention at the prevention or treatment of metabolic abnormalities and hence to target dietary management at improvement of mitochondrial function.

Preparation, structural characteristics and physiological property of resistant starch

Starch is of the most important carbohydrates in human diets for maintaining normal body's energy metabolisms. However, due to the increased number of chronic diseases worldwide, the further study of the starch property in the dietary formula becomes essential for revealing its association with preventing or intervening the occurrence of such diseases as diabetes, obesity, intestinal diseases and even cardiovascular diseases. Considering that different starches demonstrate different digestion property based on their individual structural characteristics, in particular, the existence of resistant starch (RS) attracts much more interests recently because of its being a major producer of short-chain fatty acids followed by gut microbial fermentation. Furthermore, the understanding of the interaction between RS and microbiota in the gut and its substantial influence on the regulation of diabetes, kidney, disease hypertension and others is still being under investigated. Therefore, this chapter summarized the fine structure of starch, resistant starch structural characteristics, formation and preparation of resistant starches and their corresponding physiological property.

Resistant starch intake alleviates collagen-induced arthritis in mice by modulating gut microbiota and promoting concomitant propionate production

Gut dysbiosis precedes clinic symptoms in rheumatoid arthritis (RA) and has been implicated in the initiation and persistence of RA. The early treatment of RA is critical to better clinical outcome especially for joint destruction. Although dietary interventions have been reported to be beneficial for RA patients, it is unclear to whether diet-induced gut microbiome changes can be a preventive strategy to RA development. Here, we investigated the effect of a high fiber diet (HFD) rich with resistant starch (RS) on collagen-induced arthritis (CIA) and gut microbial composition in mice. RS-HFD significantly reduced arthritis severity and bone erosion in CIA mice. The therapeutic effects of RS-HFD were correlated with splenic regulatory T cell (Treg) expansion and serum interleukin-10 (IL-10) increase. The increased abundance of Lactobacillus and Lachnoclostridium genera concomitant with CIA were eliminated in CIA mice fed the RS-HFD diet. Notably, RS-HFD also led to a predominance of Bacteroidetes, and increased abundances of Lachnospiraceae_NK4A136_group and Bacteroidales_S24-7_group genera in CIA mice. Accompanied with the gut microbiome changes, serum levels of the short-chain fatty acid (SCFA) acetate, propionate and isobutyrate detected by GC-TOFMS were also increased in CIA mice fed RS-HFD. While, addition of β-acids from hops extract to the drinking water of mice fed RS-HFD significantly decreased serum propionate and completely eliminated RS-HFD-induced disease improvement, Treg cell increase and IL-10 production in CIA mice. Moreover, exogenous propionate added to drinking water replicated the protective role of RS-HFD in CIA including reduced bone damage. The direct effect of propionate on T cells in vitro was further explored as at least one mechanistic explanation for the dietary effects of microbial metabolites on immune regulation in experimental RA. Taken together, RS-HFD significantly reduced CIA and bone damage and altered gut microbial composition with concomitant increase in circulating propionate, indicating that RS-rich diet might be a promising therapy especially in the early stage of RA.

Diet-induced rodent models of obesity-related metabolic disorders-A guide to a translational perspective

Diet is a critical element determining human health and diseases, and unbalanced food habits are major risk factors for the development of obesity and related metabolic disorders. Despite technological and pharmacological advances, as well as intensification of awareness campaigns, the prevalence of metabolic disorders worldwide is still increasing. Thus, novel therapeutic approaches with increased efficacy are urgently required, which often depends on cellular and molecular investigations using robust animal models. In the absence of perfect rodent models, those induced by excessive consumption of fat and sugars better replicate the key aspects that are the root causes of human metabolic diseases. However, the results obtained using these models cannot be directly compared, particularly because of the use of different dietary protocols, and animal species and strains, among other confounding factors. This review article revisits diet-induced models of obesity and related metabolic disorders, namely, metabolic syndrome, prediabetes, diabetes and nonalcoholic fatty liver disease. A critical analysis focused on the main pathophysiological features of rodent models, as opposed to the criteria defined for humans, is provided as a practical guide with a translational perspective for the establishment of animal models of obesity-related metabolic diseases.

Novel Short-Clustered Maltodextrin as a Dietary Starch Substitute Attenuates Metabolic Dysregulation and Restructures Gut Microbiota in db/db Mice

Molecular structure of starch in daily diet is closely associated with diabetes management. By enzymatically reassembling α-1,4 and α-1,6 glycosidic bonds in starch molecules, we have synthesized an innovative short-clustered maltodextrin (SCMD) which slowly releases glucose during digestion. Here, we investigated the potential benefits of the SCMD-containing diet using diabetic db/db mice. As compared to a diet with normal starch, this dietary style greatly attenuated hyperglycemia and repaired symptoms associated with diabetes. Additionally, in comparison with acarbose (an α-glucosidase inhibitor) administration, the SCMD-containing diet more effectively accelerated brown adipose activation and improved energy metabolism of db/db mice. Furthermore, the SCMD-containing diet was a more suitable approach to improving the intestinal microflora than acarbose administration, especially the proliferation of Mucispirillum, Akkermansia, and Bifidobacterium. These results reveal a novel strategy for diabetes management based on enzymatically rebuilding starch molecules in the daily diet.

The Effect of Soluble Fiber Dextrin on Subjective and Physiological Markers of Appetite: A Randomized Trial

Obesity is a leading public health problem throughout the world. The development of foods that increase satiety and reduce food may aid weight management. This study determined the effect of consuming soluble fiber dextrin (SFD) on appetite, appetitive hormones, breath hydrogen and food intake in adults. Forty-three participants completed this study. For each treatment, 50% of the SFD was provided in liquid form as part of breakfast and 50% in solid form as a morning snack. Appetite questionnaires, blood and breath samples were collected immediately before breakfast and at regular intervals during the test session. The participants consumed an ad libitum lunch meal, afternoon snack and dinner meal, and the amount eaten was recorded. Following dinner, participants left the laboratory but were required to keep a diet diary for the remainder of the day. Breath hydrogen concentration was significantly higher following the consumption of SFD compared to control (p < 0.05). There was no observed overall treatment effect of consuming SFD on GLP-1 (Glucagon-Like-Peptide-1), ghrelin, CCK-8 (Cholecystokinin) or PYY_3-36 (Petptide YY) (p > 0.05). Moreover, consuming foods containing SFD had no effect on subjective appetite or food intake (p > 0.05). Consuming foods containing SFD increased breath hydrogen but did not influence food intake, appetite or appetitive hormones. However, the limitations of this study may have individually or collectively masked an effect of SFD on food intake and appetite.

Targeting Carbohydrates and Polyphenols for a Healthy Microbiome and Healthy Weight

Purpose of Review

In this review, we focus on microbiota modulation using non-digestible carbohydrate and polyphenols (i.e., prebiotics) that have the potential to modulate body weight.

Recent Findings

Prebiotics derived from plants have gained the interest of public and scientific communities as they may prevent diseases and help maintain health.

Summary

Maintaining a healthy body weight is key to reducing the risk of developing chronic metabolic complications. However, the prevalence of obesity has increased to pandemic proportions and is now ranked globally in the top five risk factors for death. While diet and behavioral modification programs aiming to reduce weight gain and promote weight loss are effective in the short term, they remain insufficient over the long haul as compliance is often low and weight regain is very common. As a result, novel dietary strategies targeting the gut microbiota have been successful in decreasing obesity and metabolic disorders via different molecular mechanisms.

Effects of the amount and type of carbohydrates used in type 2 diabetes diets in animal models: A systematic review

Type 2 diabetes mellitus (T2DM) is among the most prevalent diseases in the world, affecting over 420 million people. The disease is marked by a poor metabolic effect of insulin leading to chronic hyperglycaemia, which can result in microvascular complications. It is widely known that postprandial glycaemia is reliant on the total carbohydrate content of a meal. However, the importance of the amount and the source of these carbohydrates remains controversial due to mechanisms other than insulin secretion. Oxidative stress, inflammation, pyruvate production and the quality of the intestinal microbiota, resulting in plasma lipopolysaccharides and short-chain fatty acids production, play an important role in blood sugar control and consequently in type 2 diabetes. Thus, we systematically reviewed the preclinical evidences on the impact of the amount and type of carbohydrate found in different diets and its influence on blood glucose levels in diabetic animals. We used a comprehensive and structured search in biomedical databases Medline (PubMed), Scopus and Web of Science, recovering and analyzing 27 original studies. Results showed that sucrose-rich diets deteriorated diabetic condition in animal models regardless of the total dietary carbohydrate content. On the other hand, fiber, particularly resistant starch, improved blood glucose parameters through direct and indirect mechanisms, such as delayed gastric emptying and improved gut microbiota. All studies used rodents as animal models and male animals were preferred over females. Improvements in T2DM parameters in animal models were more closely related to the type of dietary carbohydrate than to its content on a diet, i. e., resistant starch seems to be the most beneficial source for maintaining normoglycemia. Results show that current literature is at high risk of bias due to neglecting experimental methods.

Sustained effects of resistant starch on the expression of genes related to carbohydrate digestion/absorption in the small intestine

Resistant starch (RS) consumption has beneficial effects on health, such as reduced postprandial blood glucose levels. In this study, we evaluated the effect of a 14-day diet containing RS on α-glucosidase activity and the expression of genes related to carbohydrate digestion/absorption in rats. We examined whether the effects of RS persist when the rats were shifted to a control diet. The results suggest that RS consumption reduces α-glucosidase activity and Mgam, Si and Sglt1 mRNA levels in the proximal jejunum. In addition, RS consumption appeared to influence the serum GIP level, up to 2 days after the animals were shifted to a control diet. To our knowledge, this is the first report that RS has a sustained effect on gut hormone expression and the expression of genes related to carbohydrate digestion/absorption in the proximal jejunum.

Effects of resistant starch on glycemic control, serum lipoproteins and systemic inflammation in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled clinical trials

The aim of this systematic review and meta-analysis was to evaluate the effects of resistant starch (RS) on glycemic status, serum lipoproteins and inflammatory markers in patients with metabolic syndrome (MetS) and related disorders. Two independent authors systematically searched online database including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until 30 April 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. The heterogeneity among the included studies was assessed using Cochrane's Q test and I-square (I²) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. Nineteen trials were included in this meta-analysis. Administration of RS resulted in significant reduction in fasting plasma glucose (FPG) (14 studies) (WMD: -4.28; 95% CI: -7.01, -1.55), insulin (12 studies) (WMD: -1.95; 95% CI: -3.22, -0.68), and HbA1C (8 studies) (WMD: -0.60; 95% CI: -0.95, -0.24). When pooling data from 13 studies, a significant reduction in total cholesterol levels (WMD: -8.19; 95% CI: -15.38, -1.00) and LDL-cholesterol (WMD: -8.57; 95% CI: -13.48, -3.66) were found as well. Finally, RS administration was associated with a significant decrease in tumor necrosis factor alpha (TNF-α) (WMD: -2.02; 95% CI: -3.14, -0.90). This meta-analysis showed beneficial effects of RS on improving FPG, insulin, HbA1c, total cholesterol, LDL-cholesterol and TNF-α levels in patients with MetS and related disorders, but it did not affect HOMA-IR, triglycerides, HDL-cholesterol, CRP and IL-6 levels.

Functional Cereal Products in the Diet for Type 2 Diabetes Patients

Type 2 diabetes has become one of the major health problems of the modern world. It is assumed that environmental factors have a significant impact on the development of the disease, and great importance is ascribed to the diet, which can be modified accordingly. The diet can exert prophylactic and therapeutic effects; changes in the diet in advanced disease can improve the quality of life of diabetic patients and minimise the risk of complications, which are the direct cause of diabetes-related death. Functional food, which has a potentially health-enhancing effect in addition to its nutritional value, has been increasingly recognised and required. Cereal products are crucial in diabetic nutrition. Their function can additionally be enhanced by fortification with compounds with proven hypoglycaemic effects. Pasta has a low glycaemic index and is a good carrier of fortifying substances; hence, it can be highly recommended in diets for diabetic patients.

The Gut Microbiome Influences Host Endocrine Functions

The gut microbiome is considered an organ contributing to the regulation of host metabolism. Since the relationship between the gut microbiome and specific diseases was elucidated, numerous studies have deciphered molecular mechanisms explaining how gut bacteria interact with host cells and eventually shape metabolism. Both metagenomic and metabolomic analyses have contributed to the discovery of bacterial-derived metabolites acting on host cells. In this review, we examine the molecular mechanisms by which bacterial metabolites act as paracrine or endocrine factors, thereby regulating host metabolism. We highlight the impact of specific short-chain fatty acids on the secretion of gut peptides (i.e., glucagon-like peptide-1, peptide YY) and other metabolites produced from different amino acids and regulating inflammation, glucose metabolism, or energy homeostasis. We also discuss the role of gut microbes on the regulation of bioactive lipids that belong to the endocannabinoid system and specific neurotransmitters (e.g., γ-aminobutyric acid, serotonin, nitric oxide). Finally, we review the role of specific bacterial components (i.e., ClpB, Amuc_1100) also acting as endocrine factors and eventually controlling host metabolism. In conclusion, this review summarizes the recent state of the art, aiming at providing evidence that the gut microbiome influences host endocrine functions via several bacteria-derived metabolites.

Modulation of the Gut Microbiota by Resistant Starch as a Treatment of Chronic Kidney Diseases: Evidence of Efficacy and Mechanistic Insights

Chronic kidney disease (CKD) has been associated with changes in gut microbial ecology, or "dysbiosis," which may contribute to disease progression. Recent studies have focused on dietary approaches to favorably alter the composition of the gut microbial communities as a treatment method in CKD. Resistant starch (RS), a prebiotic that promotes proliferation of gut bacteria such as Bifidobacteria and Lactobacilli, increases the production of metabolites including short-chain fatty acids, which confer a number of health-promoting benefits. However, there is a lack of mechanistic insight into how these metabolites can positively influence renal health. Emerging evidence shows that microbiota-derived metabolites can regulate the incretin axis and mitigate inflammation via expansion of regulatory T cells. Studies from animal models and patients with CKD show that RS supplementation attenuates the concentrations of uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate. Here, we present the current state of knowledge linking the microbiome to CKD, we explore the efficacy of RS in animal models of CKD and in humans with the condition, and we discuss how RS supplementation could be a promising dietary approach for slowing CKD progression.

Attenuation of metabolic syndrome in the ob/ob mouse model by resistant starch intervention is dose dependent

The effect of different RS concentrations on the morphology of colon (A), liver (B) and adipose tissue (C).

Secondary Metabolites, Dietary Fiber and Conjugated Fatty Acids as Functional Food Ingredients against Overweight and Obesity

Obesity is a common serious health problem leading to many serious health disorders. This phenomenon is defined as the over-storage of lipids in adipose tissue that occurs when there is an imbalance between the energy intake and energy used. During obesity, many metabolic alterations occur that can damage several organs, such as vascular or skeletal muscle resulting in the dysfunction of these tissues. In this review, we will discuss molecular genetics and causes of obesity, some of the disorders related to human obesity as well as anti-obesity tool. An interesting solution to the obesity problem is natural substances, revealing anti-obesity activity, as well as functional food enriched with aforementioned substances. Functional foods are products exhibiting a potentially positive effect on health beyond basic nutrition. They contain well-known biologically active natural compounds, which promote optimal health and reduce the risk of many diseases, including obesity.

Metformin Alters Upper Small Intestinal Microbiota that Impact a Glucose-SGLT1-Sensing Glucoregulatory Pathway

The gut microbiota alters energy homeostasis. In parallel, metformin regulates upper small intestinal sodium glucose cotransporter-1 (SGLT1), but whether changes of the microbiota or SGLT1-dependent pathways in the upper small intestine mediate metformin action is unknown. Here we report that upper small intestinal glucose sensing triggers an SGLT1-dependent pathway to lower glucose production in rodents. High-fat diet (HFD) feeding reduces glucose sensing and SGLT1 expression in the upper small intestine. Upper small intestinal metformin treatment restores SGLT1 expression and glucose sensing while shifting the upper small intestinal microbiota partly by increasing the abundance of Lactobacillus. Transplantation of upper small intestinal microbiota from metformin-treated HFD rats to the upper small intestine of untreated HFD rats also increases the upper small intestinal abundance of Lactobacillus and glucose sensing via an upregulation of SGLT1 expression. Thus, we demonstrate that metformin alters upper small intestinal microbiota and impacts a glucose-SGLT1-sensing glucoregulatory pathway.

Resistant Starch Content of Traditional Indian Legume Preparations

Foods rich in resistant starch RS can play an important role in the management of chronic diseases. Legumes contain higher amount of RS than cereals, roots and tubers. Therefore the current study was undertaken to estimate RS content of some commonly consumed Indian legume preparations. 26 cooked legume based products including 6 readymade traditional snacks were tested for their RS content using Megazyme Assay Kit for Resistant Starch. RS content was estimated for 100 g cooked food and for the cooked portion obtained by using 30 g of major ingredient. One way ANOVA with post hoc Tukey’s test was used to compare the mean RS content in one portion of different categories of legume preparations. Level of significance was set at p<0.05. RS content of four types of plain pressure cooked dhal, common to Indian cooking, was in the range of 1.21 g% to 2.16 g% whereas aamti, a thinner preparation of dhal contained RS in the range of 0.42 g% to 0.69 g%. In both types of dhal preparations, red gram dhal showed highest RS content followed by bengal gram dhal. Usal made using bengal gram kabuli contained 2.38 g% RS followed by 1.42 g% RS in bengal gram brown usal. RS in bengal gram flour based traditional recipes like zunka, dhirda and pithle was 1.23 g%, 1.48 g% and 0.09 g% respectively. When mean RS content of one portion of different categories of legume preparations was compared, there was no significant difference p≥0.05 found among any of the categories. The results of the study generated useful data with respect to RS content in 100 g as well as RS in one portion of legume preparations and identified preparations with red gram dhal, bengal gram kabuli and brown variety and lentil as relatively higher in RS content.

Metabolic Effects of High Glycaemic Index Diets: A Systematic Review and Meta-Analysis of Feeding Studies in Mice and Rats

Low glycaemic index (LGI) diets are often reported to benefit metabolic health, but the mechanism(s) responsible are not clear. This review aimed to systematically identify studies investigating metabolic effects of high glycaemic index (HGI) versus LGI diets in mice and rats. A meta-analysis was conducted to calculate an overall effect size, Hedge's standardised mean differences (hereafter d), for each trait, with moderator variables considered in subsequent meta-regressions. Across 30 articles, a HGI diet increased five of the seven traits examined: body weight (d = 0.55; 95% confidence interval: 0.31, 0.79), fat mass (d = 1.08; 0.67, 1.49), fasting circulating insulin levels (d = 0.40; 0.09, 0.71), and glucose (d = 0.80; 0.35, 1.25) and insulin (d = 1.14; 0.50, 1.77) area under the curve during a glucose tolerance test. However, there was substantial heterogeneity among the effects for all traits and the small number of studies enabled only limited investigation of possible confounding factors. HGI diets favour body weight gain, increased adiposity and detrimentally affect parameters of glucose homeostasis in mice and rats, but these effects may not be a direct result of GI per se; rather they may be due to variation in other dietary constituents, such as dietary fibre, a factor which is known to reduce the GI of food and promote health via GI-independent mechanisms.

Spent turmeric reduces fat mass in rats fed a high-fat diet

Indigestible carbohydrates may improve obesity. Spent turmeric contains high levels of dietary fibre and resistant starch (RS), which have fermentation potential in vitro. We hypothesised that indigestible carbohydrates in spent turmeric might prevent obesity development. In the first study, rats were administered 10% turmeric powder (TP) or spent turmeric powder (STP) in a high-fat (HF) diet for 28 d. In the second study, rats were fed 10% STP in a HF diet with or without antibiotics for 15 d. In the third study, rats were treated with a STP-containing suspension. In study 1, the TP and STP diet increased the caecal short-chain fatty acid (SCFA) content compared to that of a control diet. The lower energy intake in the TP and STP group was strongly related to the decrease in visceral fat weight. In study 2, after caecal fermentation suppression with antibiotics, STP treatment decreased the visceral fat mass. In study 3, the plasma glucose levels and incremental area under the curve (AUC) after ingestion of a STP-containing suspension were lower than those after ingestion of suspension alone. These findings suggest the reduction of carbohydrate absorption during the gastrointestinal passage after TP and STP treatment. Our data indicate that the reduced obesity development in rats fed a HF diet may be attributed to the low metabolisable energy density of carbohydrates in the spent turmeric, independent of SCFA-mediated factors.

Dietary Resistant Starch Supplementation Increases High-Density Lipoprotein Particle Number in Pigs Fed a Western Diet

Resistant starch (RS) has been well characterized for its glycemic control properties; however, there is little consensus regarding the influence of RS on blood lipid concentrations and lipoprotein distribution and size. Therefore, this study aimed to characterize the effect of daily RS supplementation in a controlled capsule delivery on biomarkers of cardiovascular (blood lipids, lipoproteins) and diabetes (glucose, insulin) risk in a pig model. Twelve 8-week-old male Yorkshire pigs were placed on a synthetic Western diet and randomly divided into two groups (n = 6/group) for 30 days: (1) a placebo group supplemented with capsules containing unmodified pre-gelatinized potato starch (0 g/RS/day); and (2) an RS group supplemented with capsules containing resistant potato starch (10 g/RS/day). Serum lipids including total-cholesterol (C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides did not differ (p > 0.05) between the RS and placebo groups. Although the total numbers of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) particles were similar (p > 0.05) between the two groups, total high-density lipoprotein (HDL) particles were higher (+28%, p < 0.05) in the RS group compared with placebo, resulting from an increase (p < 0.05) in the small HDL subclass particles (+32%). Compared with the placebo group, RS supplementation lowered (p < 0.05) fasting serum glucose (-20%) and improved (p < 0.05) insulin resistance as estimated by Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) without a change in insulin. Additionally, total serum glucagon-like-peptide 1 (GLP-1) was higher (+141%, p < 0.05) following RS supplementation compared with placebo. This data suggests that in addition to the more well-characterized effect of RS intake in lowering blood glucose and improving insulin sensitivity, the consumption of RS may be beneficial in lipid management strategies by enhancing total HDL particle number.

How gut microbes talk to organs: The role of endocrine and nervous routes

Background

Changes in gut microbiota composition and activity have been associated with different metabolic disorders, including obesity, diabetes, and cardiometabolic disorders. Recent evidence suggests that different organs are directly under the influence of bacterial metabolites that may directly or indirectly regulate physiological and pathological processes.

Scope of review

We reviewed seminal as well as recent papers showing that gut microbes influence energy, glucose and lipid homeostasis by controlling different metabolic routes such as endocrine, enteric and central nervous system. These dialogues are discussed in the context of obesity and diabetes but also for brain pathologies and neurodegenerative disorders.

Major conclusions

The recent advances in gut microbiota investigation as well as the discovery of specific metabolites interacting with host cells has led to the identification of novel inter-organ communication during metabolic disturbances. This suggests that gut microbes may be viewed as “novel” future therapeutic partners.

This article is part of a special issue on microbiota.

Low protein diets produce divergent effects on energy balance

Diets deficient in protein often increase food consumption, body weight and fat mass; however, the underlying mechanisms remain poorly understood. We compared the effects of diets varying in protein concentrations on energy balance in obesity-prone rats. We demonstrate that protein-free (0% protein calories) diets decreased energy intake and increased energy expenditure, very low protein (5% protein) diets increased energy intake and expenditure, whereas moderately low protein (10% protein) diets increased energy intake without altering expenditure, relative to control diet (15% protein). These diet-induced alterations in energy expenditure are in part mediated through enhanced serotonergic and β-adrenergic signaling coupled with upregulation of key thermogenic markers in brown fat and skeletal muscle. The protein-free and very low protein diets decreased plasma concentrations of multiple essential amino acids, anorexigenic and metabolic hormones, but these diets increased the tissue expression and plasma concentrations of fibroblast growth factor-21. Protein-free and very low protein diets induced fatty liver, reduced energy digestibility, and decreased lean mass and body weight that persisted beyond the restriction period. In contrast, moderately low protein diets promoted gain in body weight and adiposity following the period of protein restriction. Together, our findings demonstrate that low protein diets produce divergent effects on energy balance.

Moderately Low Magnesium Intake Impairs Growth of Lean Body Mass in Obese-Prone and Obese-Resistant Rats Fed a High-Energy Diet

The physical and biochemical changes resulting from moderately low magnesium (Mg) intake are not fully understood. Obesity and associated co-morbidities affect Mg metabolism and may exacerbate Mg deficiency and physiological effects. Male rats selectively bred for diet-induced obesity (OP, obese-prone) or resistance (OR, obese-resistant) were fed a high-fat, high-energy diet containing moderately low (LMg, 0.116 ± 0.001 g/kg) or normal (NMg, 0.516 ± 0.007 g/kg) Mg for 13 weeks. The growth, body composition, mineral homeostasis, bone development, and glucose metabolism of the rats were examined. OP and OR rats showed differences (p < 0.05) in many physical and biochemical measures regardless of diet. OP and OR rats fed the LMg diet had decreased body weight, lean body mass, decreased femoral size (width, weight, and volume), and serum Mg and potassium concentrations compared to rats fed the NMg diet. The LMg diet increased serum calcium (Ca) concentration in both rat strains with a concomitant decrease in serum parathyroid hormone concentration only in the OR strain. In the femur, Mg concentration was reduced, whereas concentrations of Ca and sodium were increased in both strains fed the LMg diet. Plasma glucose and insulin concentrations in an oral glucose tolerance test were similar in rats fed the LMg or NMg diets. These results show that a moderately low Mg diet impairs the growth of lean body mass and alters femoral geometry and mineral metabolism in OP and OR rats fed a high-energy diet.

Bioactive Plant Metabolites in the Management of Non-Communicable Metabolic Diseases: Looking at Opportunities beyond the Horizon

There has been an unprecedented worldwide rise in non-communicable metabolic diseases (NCDs), particularly cardiovascular diseases (CVD) and diabetes. While modern pharmacotherapy has decreased the mortality in the existing population, it has failed to stem the rise. Furthermore, a large segment of the world population cannot afford expensive pharmacotherapy. Therefore, there is an urgent need for inexpensive preventive measures to control the rise in CVD and diabetes and associated co-morbidities. The purpose of this review is to explore the role of food bioactives in prevention of NCDs. To this end, we have critically analyzed the possible utility of three classes of food bioactives: (a) resistant starch, a metabolically resistant carbohydrate known to favorably modulate insulin secretion and glucose metabolism; (b) cyclo (His-Pro), a food-derived cyclic dipeptides; and (c) polyphenol-rich berries. Finally, we have also briefly outlined the strategies needed to prepare these food-bioactives for human use.

Is there any place for resistant starch, as alimentary prebiotic, for patients with type 2 diabetes?

OBJECTIVE

The aim of the present study was to determine effects of Resistant Starch (RS2) on metabolic parameters and inflammation in women with type 2 diabetes (T2DM).

METHODS

In this randomized controlled clinical trial, 60 females with T2DM were divided into intervention (n = 28) and placebo groups (n = 32). They received 10 g/d RS2 or placebo for 8 weeks, respectively. Fasting blood sugar (FBS), glycated hemoglobin (HbA1c), lipid profile, high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were measured at baseline and at the end of the trial. Paired t test, unpaired t-test and ANCOVA were used to compare the quantitative variables. The data were analyzed using SPSS software version 13.0.

RESULTS

RS2 decreased HbA1c (-0.3%, -3.6%), TNF-α (-3.4 pg/mL, -18.9%), triglyceride (-33.4 mg/dL, -15.4%), and it increased HDL-c (+9.4 mg/dL, +24.6%) significantly compared with the placebo group (p < 0.05). Changes in FBS, total cholesterol, low-density lipoprotein, hs-CRP and IL-6 were not significant in the RS2 group compared with the control group. RS2 can improve glycemic status, inflammatory markers and lipid profile in women with T2DM.

CONCLUSIONS

Although findings of the present study indicated positive effects of RS2 on inflammation and metabolic parameters, more studies are needed to confirm efficacy of RS2 as an adjunct therapy in diabetes.

The Intra- or Extracellular Redox State Was Not Affected by a High vs. Low Glycemic Response Diet in Mice

A low glycemic response (LGR) vs. high glycemic response (HGR) diet helps curtail the development of obesity and diabetes, though the mechanisms are unknown. We hypothesized that consumption of a HGR vs. a LGR diet would lead to a more oxidized circulating redox state and predicted that a HGR diet would increase fat accumulation, reduce insulin sensitivity, and impair metabolic acclimation to a high fat diet in a mouse model. Hence, male C57BL/6 mice consumed a HGR or LGR diet for 16 weeks and a subset of the mice subsequently consumed a high fat diet for 4 weeks. We found that body mass increased at a faster rate for those consuming the HGR diet. Percent body fat was greater and percent lean mass was lesser in the HGR group starting at 12 weeks. However, the groups did not differ in terms of glucose tolerance at week 14 and metabolic parameters (respiratory exchange ratio, heat production, activity) at weeks 4 or 15. Moreover, mice on either diet did not show differences in metabolic acclimation to the high fat leg of the study. At the termination of the study, the groups did not differ in terms of redox pairs (lactate/pyruvate and β-hydroxybutyrate/acetoacetate) or thioredoxin reductase activity in blood. Also, total and oxidized glutathione levels and lipid peroxidation were similar in blood and liver. Correlations between baseline measures, longitudinal parameters, environmental conditions, and terminal metrics revealed that individual mice have innate propensities to metabolic regulation that may be difficult to perturb with diet alone; for example, starting mass correlated negatively with energy expenditure 4 weeks into the study and total hepatic glutathione at the end of the study. In conclusion, these data suggest that the mechanism by which HGR carbohydrates contributes to obesity is not via prolonged oxidation of the circulating redox state.

Effects of dietary amylose/amylopectin ratio on growth performance, feed utilization, digestive enzymes, and postprandial metabolic responses in juvenile obscure puffer Takifugu obscurus

The effect of dietary amylose/amylopectin (AM/AP) ratio on growth, feed utilization, digestive enzyme activities, plasma parameters, and postprandial blood glucose responses was evaluated in juvenile obscure puffer, Takifugu obscurus. Five isonitrogenous (430 g kg(-1) crude protein) and isolipidic (90 g kg(-1) crude lipid) diets containing an equal starch level (250 g kg(-1) starch) with different AM/AP ratio diets of 0/25, 3/22, 6/19, 9/16 and 12/13 were formulated. Each experimental diet was fed to triplicate groups (25 fish per tank), twice daily during a period of 60 days. After the growth trial, a postprandial blood response test was carried out. Fish fed diet 6/19 showed best growth, feed efficiency and protein efficiency ratio. Hepatosomatic index, plasma total cholesterol concentration, liver glycogen and lipid content, and gluconokinase, pyruvate kinase and fructose-1,6-bisphosphatase activities were lower in fish fed highest AM/AP diet (12/13) than in fish fed the low-amylose diets. Activities of liver and intestinal trypsin in fish fed diet 3/22 and diet 6/19 were higher than in fish fed diet 9/16 and diet 12/13. Activities of liver and intestinal amylase and intestinal lipase, and starch digestibility were negatively correlated with dietary AM/AP ratio. Fish fed diet 3/22 and diet 6/19 showed higher plasma total amino acid concentration than fish fed the other diets, while plasma urea nitrogen concentration and activities of alanine aminotransferase and aspartate aminotransferase showed the opposite trend. Equal values were found for viscerosomatic index and condition factor, whole body and muscle composition, plasma high-density and low-density lipoprotein cholesterol concentrations, and activities of lipase and hexokinase and glucose-6-phosphatase in liver. Postprandial plasma glucose and triglyceride peak value of fish fed diet 12/13 were lower than in fish fed the low-amylose diets, and the peak time of plasma glucose was later than in fish fed the other diets. Plasma glucose and triglyceride concentrations showed a significant difference at 2 and 4 h after a meal and varied between dietary treatments. According to regression analysis of weight gain against dietary AM/AP ratio, the optimum dietary AM/AP ratio for maximum growth of obscure puffer was 0.25. The present result indicates that dietary AM/AP ratio could affect growth performance and feed utilization, some plasma parameters, digestive enzyme as well as hepatic glucose metabolic enzyme activities in juvenile obscure puffer.

Gut microbiota and GLP-1

A large body of evidence suggests that the regulation of energy balance and glucose homeostasis by fermentable carbohydrates induces specific changes in the gut microbiota. Among the mechanisms, our research group and others have demonstrated that the gut microbiota fermentation (i.e., bacterial digestion of specific compounds) of specific prebiotics or other non-digestible carbohydrates is associated with the secretion of enteroendocrine peptides, such as the glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), produced by L-cells. In this review, we highlight past and recent results describing how dietary manipulation of the gut microbiota, using nutrients or specific microbes, can stimulate GLP-1 secretion in rodents and humans. Furthermore, the purpose of this review is to discuss the putative mechanisms by which specific bacterial metabolites, such as short chain fatty acids, trigger GLP-1 secretion through GPR41/43-dependent mechanisms. Moreover, we conclude by discussing the molecular advance showing that the endocannabinoid system or related bioactive lipids modulated by the gut microbiota may contribute to the regulation of glucose, lipid and energy homeostasis.

Estimation of Resistant Starch Content of Selected Routinely Consumed Indian Food Preparations

Resistant Starch, an important component of the diet, shows the potential health benefits against lifestyle diseases and many other health conditions. Resistant Starch (RS) refers to the portion of starch and starch products that resist digestion as it passes through the gastrointestinal tract, gets fermented in the colon by colonic microflora and produces short chain fatty acids which directly or indirectly help in preventing and/or controlling many diseases.Since the main sources of RS in the Indian diet are starchy foods like varieties of cereals, cereal products, roots and tubers, raw and processed legumes etc.it becomes important to determine the RS content of typical traditional Indian starchy cereal and legume preparations.Therefore the aim of this research was to estimate the RS content of selected, routinely consumed Indian food preparations and to determine the change in RS content of cereal and pulse preparations on cooking and on storage. RS content was estimated for two varieties of rice and four rice preparations, whole and refined wheat flour and four preparations made using these flours, legumes like whole moong, Kabuli chhana, Chana flour and preparations made using them. Five of these preparations were also analyzed for their RS content after an overnight storage in the refrigerator, to understand the effect of storage on their RS content.Amount of RS was estimated using the procedure given by Parchure and Kulkarni. RS content in freshly cooked preparations was compared with RS content in equivalent amount of raw ingredients. RS content of freshly cooked preparations was also compared with RS in equivalent amount of cooked and stored samples. Comparison of means was done using paired t test. One-way ANOVA was also used to compare RS content of freshly cooked rice preparations, wheat preparations and legume preparations. P ≤ 0.05 was considered statistically significant.The RS content of raw food samples ranged from as low as 0.50g% in whole wheat flour to 27.67g% in Kolam rice. The two varieties of rice, Basmati and Kolam contained 20.22g% and 27.67g% RS respectively whereas Whole wheat flour and Refined wheat flour contained 0.50g% and 0.65g% RS respectively. The RS in raw legumes was 1.93g%, 1.98g% and 4.52g% in Kabuli Chana, Chana flour and Whole Moongrespectively.Among four freshly cooked rice preparations RS varied from 0.46g% in cooked Kolam to 0.78g% in Khichdi. Among four wheat preparations (freshly cooked) RS content varied from 0.47g% in Puri to 0.61g% (food as eaten) in paratha. Chapatti and Bhatura contained 0.49g% and 0.54g% RS (food as eaten) respectively.RS in legume preparations ranged from 0.09g% in freshly cooked Pithle to 2.38g% in cooked Chole. The RS values for germinated Moong, MoongUsal, and soaked Kabuli chana were 0.79g%, 0.87g% and 0.73g% (food as eaten) respectively.In case of rice preparations RS content was significantly lower in all the four freshly cooked rice products as compared to RS in equivalent amount of raw rice. All freshly cooked wheat products showed increase in RS content after cooking as compared to their corresponding raw equivalents. Except for Bhatura, in which the increase was not significant, in the rest of wheat preparations the increase was statistically significant. In case of processed or cooked legume preparations, except for chole, significantly lower RS was found in all preparations as compared to their raw equivalent quantities.In all the preparations that were subjected to storage, RS content increased after an overnight storage. A significant increase was seen in pressure cooked and stored Kolam Rice.Comparison among freshly cooked rice preparations showed that Khichdi contained significantly higher amount of RS as compared to other rice preparations, whereasamong freshly made wheat preparations, highest RS content was observed in Paratha. The RS value for Paratha was significantly higher than chapatti and puri. Among legume preparations Chhole had significantly higher RS content than moong usal or pithle. To conclude, the findings of this research show that Resistant Starch content of food preparation is influenced by many factors such as cooking method, processing technique, storage. Considering that Indians consume a vast variety of starchy preparations, further research in this direction is needed, to create a complete database of Resistant Starch content of Indian starchy preparations, that are made using different cooking and processing techniques and stored under varied conditions.

Growth, Feed Utilization and Blood Metabolic Responses to Different Amylose-amylopectin Ratio Fed Diets in Tilapia (Oreochromis niloticus)

A feeding trial was conducted in tilapia to determine the growth performance, nutrient digestibility, digestive enzymes, and postprandial blood metabolites in response to different dietary amylose-amylopectin ratios. Five isonitrogenous and isolipidic diets containing an equal starch level with different amylose-amylopectin ratios of 0.11 (diet 1), 0.24 (diet 2), 0.47 (diet 3), 0.76 (diet 4) and 0.98 (diet 5) were formulated using high-amylose corn starch (as the amylose source) and waxy rice (as the amylopectin source). Each diet was hand-fed to six tanks of 15 fish each, three times a day over a 6-wk period. After the growth trial, a postprandial blood metabolic test was carried out. Fish fed diet 2 exhibited the highest percent weight gain and feed efficiency and protein efficiency ratio, whereas fish fed with diet 5 showed the lowest growth and feed utilization among treatments. The digestibility for starch in fish fed diet 1 and 2 was higher than those in fish fed with other diets (p<0.05). The highest activities for protease, lipase and amylase were found in fish fed the diet 2, diet 1, and diet 1 respectively among dietary treatments, while the lowest values for these indexes were observed in fish fed the diet 3, diet 5 and diet 4, respectively. The liver glycogen concentrations in fish fed diets 4 and 5 were found higher than in fish fed other diets (p<0.05). The feeding rate, hepatosomatic index, condition factor, and plasma parmeters (glucose, triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol) did not differ across treatments. In terms of postprandial blood responses, peak blood glucose and triglycerides were lower after 3 or 6 h in the fish fed with diets 3-5 than in the fish fed diet 1, but delayed peak blood total amino acid time was observed in fish fed with the diets 1 or 2. The lowest peak values for each of the three blood metabolites were observed in fish fed diet 5. The results indicate that high-dietary amylose-amylopectin ratio could compromise growth, but help in reducing the blood glucose stress on fish caused by postprandial starch load.

Saccharomyces boulardii administration changes gut microbiota and reduces hepatic steatosis, low-grade inflammation, and fat mass in obese and type 2 diabetic db/db mice

Growing evidence shows that gut microbes are key factors involved in the regulation of energy homeostasis, metabolic inflammation, lipid metabolism, and glucose metabolism. Therefore, gut microbiota modulations caused by selectively fermented oligosaccharides or probiotic bacteria constitute an interesting target in the physiopathology of obesity. However, to date, no probiotic yeast has been investigated in this context. Therefore, our study aimed to evaluate the impact of the most-studied probiotic yeast (i.e., Saccharomyces boulardii Biocodex) on obesity and associated metabolic features, such as fat mass development, hepatic steatosis, and low-grade inflammation, in obese mice. S. boulardii was administered daily by oral gavage to leptin-resistant obese and type 2 diabetic mice (db/db) for 4 weeks. We found that S. boulardii-treated mice exhibited reduced body weight, fat mass, hepatic steatosis, and inflammatory tone. Interestingly, these effects of S. boulardii on host metabolism were associated with local effects in the intestine. S. boulardii increased cecum weight and cecum tissue weight but also induced dramatic changes in the gut microbial composition at the phylum, family, and genus levels. These gut microbiota changes in response to S. boulardii may also be correlated with the host metabolism response. In conclusion, this study demonstrates for the first time that S. boulardii may act as a beneficial probiotic treatment in the context of obesity and type 2 diabetes.

To date, no probiotic yeast have been investigated in the context of obesity and type 2 diabetes. Here we found that type 2 diabetic and obese mice (db/db) treated with Saccharomyces boulardii exhibited reduced body weight, fat mass, hepatic steatosis, and inflammatory tone. These effects on host metabolism were associated with local effects in the intestine. Importantly, by using pyrosequencing, we found that S. boulardii treatment induces changes of the gut microbiota composition at the phylum, family, and genus levels. Moreover, we found that gut microbiota changes in response to S. boulardii were correlated with several host metabolism responses.

Resistant starch: promise for improving human health

Ongoing research to develop digestion-resistant starch for human health promotion integrates the disciplines of starch chemistry, agronomy, analytical chemistry, food science, nutrition, pathology, and microbiology. The objectives of this research include identifying components of starch structure that confer digestion resistance, developing novel plants and starches, and modifying foods to incorporate these starches. Furthermore, recent and ongoing studies address the impact of digestion-resistant starches on the prevention and control of chronic human diseases, including diabetes, colon cancer, and obesity. This review provides a transdisciplinary overview of this field, including a description of types of resistant starches; factors in plants that affect digestion resistance; methods for starch analysis; challenges in developing food products with resistant starches; mammalian intestinal and gut bacterial metabolism; potential effects on gut microbiota; and impacts and mechanisms for the prevention and control of colon cancer, diabetes, and obesity. Although this has been an active area of research and considerable progress has been made, many questions regarding how to best use digestion-resistant starches in human diets for disease prevention must be answered before the full potential of resistant starches can be realized.