Unraveling the nutritional potential of millet by-products through extraction of high value compounds for the development of novel food products

Millets are drought-resistant crops that generate significant amount of by-products (bran, husk, stalk etc.) during harvesting and processing. These by-products are storehouse of nutrients and high value compounds including polyphenols, dietary fiber, proteins etc. However, these by-products remain underutilized and generally discarded, burned or used as feedstock causing adverse impact on the environment and human health in addition to loss of valuable nutrients. Therefore, the valorization of millet by-products offers sustainable approach to enhance food product innovation while reducing agricultural waste. Green extraction techniques can be employed to recover antioxidants, phenolics, and bioactive peptides from these by-products. The incorporation of these ingredients into food products can significantly improve the nutritional profile, functional characteristics, like antioxidant, prebiotic, anti-diabetic, and anticarcinogenic properties. The review highlights the feasibility of upcycling millet by-products into high-value components, which can address the growing demand for health-oriented food products contributing towards food security, sustainability and circular economy.

Prevention of high-fat-diet-induced obesity in mice by soluble dietary fiber from fermented and unfermented millet bran

Obesity-related diabetes, cardiovascular disease, and hypertension pose many risks to human health. Thus, mice on a high-fat diet were gavaged with millet bran (unfermented/fermented) soluble dietary fiber (RSDF/FSDF, 500 mg·kg-1) for 10 weeks in current research, and then evaluated the various biological indicators. These findings revealed that RSDF and FSDF supplements could prevent fat synthesis by inhibiting sterol regulatory element-binding protein-1c gene expression. The RSDF supplements can also accelerate fat catabolism through enhanced the mRNA expression levels of adipose triglyceride lipase and peroxisome proliferator-activated receptor α. FSDF supplements can prevent obesity by decreasing 3-hydroxy-3-methyl-glutaryl-CoA reductase expression and increasing cholesterol 7α-hydroxylase expression. Moreover, FSDF also controls obesity development by lowering total cholesterol and low-density lipoprotein cholesterol levels in the blood, triglyceride, total cholesterol, and bile acid levels in the liver. Notably, FSDF supplements can promote Bacteroides and Prevotella propagation; excretive propionic acid binds to free fatty acid receptor 2/3 and then stimulates intestinal epithelial cells to generate glucagon-like-peptide-1 and peptide YY, which can reduce food and energy intake and ultimately prevent obesity. All evidence suggests that FSDF supplements play a crucial role in preventing obesity.

Fermented natto powder alleviates obesity by regulating LXR pathway and gut microbiota in obesity rats

AIM

This study aimed to investigate the positive effect of natto powder on obese rats fed with a high-fat diet (HFD).

METHODS AND RESULTS

Sprague-Dawley rats were fed with a HFD for 8 weeks continuously and gavaged with natto powder, respectively, for 8 weeks starting from the ninth week. The results showed that natto powder significantly reduced the body weight of rats and maintained the balance of cholesterol metabolism in the body by inhibiting the activity of liver X receptors (LXR) target genes, increasing the active expression of cholesterol 7 alpha-hydroxylase, and reducing the active expression of sterol-regulatory element-binding protein and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR). Furthermore, natto powder increased the relative abundance of potentially beneficial microbiota in gut and decreased the relative abundance of obesity-related harmful bacteria, and also increased the Bacteroidetes/Firmicutes ratio and improved the composition of gut microbiota.

CONCLUSIONS

Natto powder maintains the balance of cholesterol metabolism by inhibiting the LXR pathway and regulating the gut microbiota.

Involvement of intestinal flora and miRNA into the mechanism of coarse grains improving type 2 diabetes: an overview

The prevalence of type 2 diabetes has been growing at an increasing rate worldwide. Dietary therapy is probably the easiest and least expensive method to prevent and treat diabetes. Previous studies have reported that coarse grains have anti-diabetic effects. Although considerable efforts have been made on the anti-diabetic function of different grains, the mechanisms of coarse grains on type 2 diabetes have not been systematically compared and summarized so far. Intestinal flora, reported as the main 'organ' of action underlying coarse grains, is an important factor in the alleviation of type 2 diabetes by coarse grains. Furthermore, microRNA (miRNA), as a new disease marker and 'dark nutrient', plays a likely influential role in cross-border communication among coarse grains, intestinal flora, and hosts. Given this context, this article reviews several possible mechanisms for the role of coarse grains on diabetes, incorporating resistance to inflammation and oxidative stress, repair of insulin signaling and β-cell dysfunction, and highlights the regulation of intestinal flora disorders and miRNAs expression, along with some novel insights. © 2022 Society of Chemical Industry.

Exploring the underutilized novel foods and starches for formulation of low glycemic therapeutic foods: a review

Rising incidences of life-style disorders like obesity, diabetes and cardiovascular diseases are a matter of concern coupled with escalated consumption of highly refined and high energy foods with low nutrient density. Food choices of consumers have witnessed significant changes globally with rising preference to highly processed palatable foods. Thus, it calls food scientists, researchers and nutritionists' attention towards developing and promoting pleasant-tasting yet healthy foods with added nutritional benefits. This review highlights selected underutilized and novel ingredients from different food sources and their by-products that are gaining popularity because of their nutrient density, that can be employed to improve the nutritional quality of conventionally available empty-calorie foods. It also emphasizes on the therapeutic benefits of foods developed from these understudied grains, nuts, processing by-products of grains, fruits- and vegetable-byproducts and nutraceutical starches. This review aims to draw attention of food scientists and industrialists towards popularizing the utilization of these unconventional, yet nutrient rich foods sources in improving the nutritional profile of the conventional foods lacking in nutrient density.

Modified cereal bran (MCB) from finger millet, kodo millet, and rice bran prevents high-fat diet-induced metabolic derangements

Cereal bran consumption improves gastrointestinal and metabolic health. Unprocessed cereal brans have a limited shelf-life and contain anti-nutrient phytochemicals. In the present study, lipids and antinutrients (flavonoids, tannin, and polyphenol) were removed from finger millet, kodo millet and rice bran using chemo-enzymatic processing. The thus-obtained modified cereal brans (MCBs) were evaluated for their potential in preventing high fat diet (HFD)-induced obesity. C57BL/6 mice were fed a HFD or a HFD supplemented with 10% w/w modified finger millet bran (mFMB), modified kodo millet bran (mKMB), modified rice bran (mRB), or a combination of the modified brans (1 : 1 : 1) for twelve weeks. The MCBs reduced HFD-induced body weight gain, improved glucose homeostasis, decreased the Firmicutes/Bacteroidetes ratio, and increased the short chain fatty acid (SCFA) levels in the cecum. Liver dyslipidemia, oxidative stress, inflammation, visceral white adipose tissue (vWAT) hypertrophy, and lipolysis were also prevented by the MCBs. Among the individual MCBs, mRB showed a greater effect in preventing HFD-induced increase in the inflammatory cytokines (IL-6, TNF-α, and LPS) than mFMB and mKMB. mFMB and mKMB supplementation more significantly restored the relative abundance of Akkermansia muciniphila and butyrate-producing genera such as Lachnospiraceae, Eubacterium, and Ruminococcus than mRB. Ex vivo gut permeability assay, immunohistochemistry of tight junction proteins, and gene expression analysis in the colon revealed that the combination of three brans was better in preventing HFD-induced leaky gut in comparison to the individual brans. Hierarchical clustering analysis showed that the combination group was clustered closest to the NPD group, suggesting an additive effect. Our study implies that a combination of mFMB, mKMB, and mRB could be used as a nutraceutical or functional food ingredient for preventing HFD-induced gut derangements and associated metabolic complications.

Nutritional and health-promoting attributes of millet: current and future perspectives

Millet is consumed as a staple food, particularly in developing countries, is part of the traditional diet in a number of relatively affluent countries, and is gaining popularity throughout the world. It is a valuable dietary energy source. In addition to high caloric value, several health-promoting attributes have been reported for millet seeds. This review describes many nutritional characteristics of millet seeds and their derivatives that are important to human health: antioxidant, antihypertensive, immunomodulatory or anti-inflammatory, antibacterial or antimicrobial, hypocholesterolemic, hypoglycemic, and anti-carcinogenic potential, and their role as modulators of gut health. There are several varieties, but the main focus of this review is on pearl millet (Cenchrus americanus [synonym Pennisetum glaucum]), one of the most widely eaten millet crops grown in India, though other millet types are also covered. In this article, the health-promoting properties of the natural components (ie, proteins, peptides, polyphenols, polysaccharides, oil, isoflavones, etc.) present in millet seeds are discussed. Although many of these health benefits have been demonstrated using animal models in vitro studies, human intervention-feeding trials are required to confirm several of the potential health benefits of millet seeds. Based on the nutritional and health-promoting attributes known for pearl millet (discussed in this review), finger millet and foxtail millet are suggested as good candidates for use in future nutritional interventions for improved human health.

Lactobacillus plantarum FRT4 alleviated obesity by modulating gut microbiota and liver metabolome in high-fat diet-induced obese mice

Background

Obesity has become a global epidemic recognized by the World Health Organization. Probiotics supplementation has been shown to contribute to improve lipid metabolism. However, mechanisms of action of probiotics against obesity are still not clear. Lactobacillus plantarum FRT4, a probiotic previously isolated from a kind of local yogurt, had good acid and bile salt tolerance and lowered cholesterol in vitro.

Objective

This study aimed to evaluate the effect of L. plantarum FRT4 on serum and liver lipid profile, liver metabolomics, and gut microbiota in mice fed with a high-fat diet (HFD).

Design

Mice were fed with either normal diet or HFD for 16 weeks and administered 0.2 mL of 1 × 10⁹ or 1 × 10¹⁰ CFU/mL dosage of L. plantarum FRT4 during the last 8 weeks of the diet. Cecal contents were analyzed by 16S rRNA sequencing. Hepatic gene expression and metabolites were detected by real-time quantitative polymerase chain reaction (PCR) and metabolomics, respectively.

Results

L. plantarum FRT4 intervention significantly reduced the HFD-induced body weight gain, liver weight, fat weight, serum cholesterol, triglyceride, and alanine aminotransferase (ALT) levels in the liver (P < 0.05). Liver metabolomics demonstrated that the HFD increased choline, glycerophosphocholine, and phosphorylcholine involved in the glycerophospholipid metabolism pathway. All these changes were reversed by FRT4 treatment, bringing the levels close to those in the control group. Further mechanisms showed that FRT4 favorably regulated gut barrier function and pro-inflammatory biomediators. Furthermore, FRT4 intervention altered the gut microbiota profiles and increased microbial diversity. The relative abundances of Bacteroides, Parabateroides, Anaerotruncus, Alistipes, Intestinimonas, Butyicicoccus, and Butyricimonas were significantly upregulated. Finally, Spearman's correlation analysis revealed that several specific genera were strongly correlated with glycerophospholipid metabolites (P < 0.05).

Conclusions

These findings suggested that L. plantarum FRT4 had beneficial effects against obesity in HFD-induced obese mice and can be used as a potential functional food for the prevention of obesity.

Obesity-associated biochemical markers of inflammation and the role of grain phytochemicals

The incidence of obesity or excessive fat accumulation in the body is increasing worldwide and has become one of the major growing health problems. Obese condition is linked with an increased level of body lipids, oxidative stress, and expression of inflammatory markers. This leads to plasma and hepatic hyperlipidemia, activation of proinflammatory cytokines (TNF-α, IL-6, and IL-1β), and transcriptional factors, which in turn lead to a high risk of cardiovascular diseases, insulin resistance, diabetes, asthma, rheumatological problem, and liver failure. Grains are the major staple food crops grown for consumption in most of the developing countries. Cereals and millets, such as rice, wheat, maize, barley, finger millet, foxtail millet, proso millet, kodo millet in the whole form with bran, germ, and endosperm, are found to be rich in phytochemicals, such as phenolics acids, vitamin E, phytosterols, carotenoids, antioxidants, dietary fiber, which have a potential health benefit on various lifestyle disorders. In this article, we summarize the findings and investigations regarding the anti-inflammatory effect of various grain phytochemicals in in vitro and in vivo models and their potential health benefits. PRACTICAL APPLICATIONS: The occurrence of obesity is rising globally and is becoming a major health concern. Obesity will lead to multiple health problems due to oxidative and inflammatory stress in the body. Whole forms of cereals and millets consumptions have shown to reduce the risk of metabolic disorders and several chronic diseases. Potential bioactive components in various grains will act on the inhibition ofbiochemical markers connected with inflammation and adipogenesis.

A Review: Cereals on Modulating the Microbiota/Metabolome for Metabolic Health

PURPOSE OF REVIEW

Diet can modulate both the composition and functionality of the human gut microbiota. Cereals are rich in specific macro and functional elements that are considered important dietary components for maintaining human health; therefore, it is important to examine precise nutritional mechanism involved in exerting the health benefits via modulating gut microbiota. The purpose of this review is to summarize recent research on how different cereals in the diet can regulate the microbiota for health and disease.

RECENT FINDINGS

There is an increased interest in targeting the gut microbiome for the treatment of chronic diseases. Cereals can alter the gut microbiome and may improve energy and glucose homeostasis, interfere with host energy homeostasis, appetite, blood glucose regulation, insulin sensitivity, and regulation of host metabolism. However, more human research is necessary to confirm the beneficial health outcomes of cereals via modulating gut microbiota. Cereals play an essential role in shaping the intestinal microbiota that contributes to exerting health effects on various diseases.

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.

The Beneficial Effect of Coarse Cereals on Chronic Diseases through Regulating Gut Microbiota

In recent years, chronic diseases including obesity, diabetes, cancer, cardiovascular, and neurodegenerative disorders have been the leading causes of incapacity and death globally. Increasing evidence suggests that improvements of lifestyle habits and diet is the most commonly adopted strategy for the prevention of chronic disorders. Moreover, many dietary compounds have revealed health-promoting benefits beyond their nutritional effects. It is worth noting that diet plays an important role in shaping the intestinal microbiota. Coarse cereals constitute important sources of nutrients for the gut microbiota and contribute to a healthy gut microbiome. Furthermore, the gut microbiota converts coarse cereals into functional substances and mediates the interaction between the host and these components. In this study, we summarize the recent findings concerning functional components of cereal grains and their potential chemopreventive activity via modulating the gut microbiota.

A comparison between whole mung bean and decorticated mung bean: beneficial effects on the regulation of serum glucose and lipid disorders and the gut microbiota in high-fat diet and streptozotocin-induced prediabetic mice

The aim of this study is to investigate the beneficial effects of whole mung bean (WMB) and decorticated mung bean (DMB) on the regulation of serum glucose and lipid disorders in high-fat diet (HFD) and streptozotocin (STZ)-induced prediabetic mice, and to further explore their gut microbiota modulatory effects. In the present study, the ability of mung bean-based diets to combat prediabetes-related metabolic disorders was determined by assessing the changes in the physiological, biochemical, and histological parameters, and the gut microbiota composition of prediabetic mice. The supplementation of both WMB and DMB can effectively alleviate HFD and STZ-induced impaired glucose tolerance (P < 0.05), which was accompanied by improvements in pancreatic β-cell damage and hepatic steatosis. However, only WMB supplementation significantly decreased the fasting blood glucose and fasting serum insulin levels by sensitizing insulin action (P < 0.05), and reduced the serum lipid profiles and glycosylated serum protein levels (P < 0.05). Furthermore, high-throughput pyrosequencing of the 16S rRNA gene revealed that WMB and DMB supplementation could prevent HFD and STZ-induced gut microbiota dysbiosis, especially for the enrichment of some benign bacteria, such as Bifidobacterium and Akkermansia, and the reduction of some harmful bacteria (Staphylococcus and Enterococcus). Overall, although decortication processing had an impact on the beneficial effects of mung bean, it did not cause the loss of all health benefits.

Polyphenol rich extracts of finger millet and kodo millet ameliorate high fat diet-induced metabolic alterations

Finger millet (FM) and kodo millet (KM) are known for their multiple health benefits. Several studies have indicated the antioxidant and hypoglycemic potential of polyphenol rich extracts (PREs) from them. However, the protective roles of PREs from these millets in overcoming high-fat diet (HFD)-induced obesity have not yet been investigated. This study aimed to identify the polyphenols in FM-PREs and KM-PREs using HPLC-DAD/ESI-MS, and to evaluate the role of PREs in mitigating lipopolysaccharide induced inflammation in murine macrophage cells and in the reduction of HFD-induced metabolic complications using male Swiss albino mice. The results suggested that KM-PRE had higher polyphenol content than FM-PRE, of which taxifolin (98%) and catechin (86.6%) were the major fractions respectively. FM-PRE and KM-PRE prevented obesity, however, KM-PRE was more profound in preventing weight gain, adipose tissue hypertrophy, hepatic steatosis, and systemic inflammation than FM-PRE. This study suggests that FM-PRE and KM-PRE could be exploited for developing functional foods or nutraceuticals against obesity and comorbidities.

The role of the microbiome in the neurobiology of social behaviour

Microbes colonise all multicellular life, and the gut microbiome has been shown to influence a range of host physiological and behavioural phenotypes. One of the most intriguing and least understood of these influences lies in the domain of the microbiome's interactions with host social behaviour, with new evidence revealing that the gut microbiome makes important contributions to animal sociality. However, little is known about the biological processes through which the microbiome might influence host social behaviour. Here, we synthesise evidence of the gut microbiome's interactions with various aspects of host sociality, including sociability, social cognition, social stress, and autism. We discuss evidence of microbial associations with the most likely physiological mediators of animal social interaction. These include the structure and function of regions of the 'social' brain (the amygdala, the prefrontal cortex, and the hippocampus) and the regulation of 'social' signalling molecules (glucocorticoids including corticosterone and cortisol, sex hormones including testosterone, oestrogens, and progestogens, neuropeptide hormones such as oxytocin and arginine vasopressin, and monoamine neurotransmitters such as serotonin and dopamine). We also discuss microbiome-associated host genetic and epigenetic processes relevant to social behaviour. We then review research on microbial interactions with olfaction in insects and mammals, which contribute to social signalling and communication. Following these discussions, we examine evidence of microbial associations with emotion and social behaviour in humans, focussing on psychobiotic studies, microbe-depression correlations, early human development, autism, and issues of statistical power, replication, and causality. We analyse how the putative physiological mediators of the microbiome-sociality connection may be investigated, and discuss issues relating to the interpretation of results. We also suggest that other candidate molecules should be studied, insofar as they exert effects on social behaviour and are known to interact with the microbiome. Finally, we consider different models of the sequence of microbial effects on host physiological development, and how these may contribute to host social behaviour.

Neural Protective Effects of Millet and Millet Polyphenols on High-Fat Diet-Induced Oxidative Stress in the Brain

A high fat diet (HFD) is considered to be a risk factor for the development of dementia because it increases oxidative stress in the brain; thus, diets rich in antioxidants, such as polyphenols, may protect against oxidative damage. In this study, we explored the antioxidant activity and neural protective function of millet on high fat diet-induced oxidative stress in rat brains. Our results suggested that the intake of millet could alleviate oxidative stress in the hippocampus and downregulate the expression of the Alzheimer's disease (AD)-related genes amyloid precursor protein (App), tau, and γ-secretase. Furthermore, we extracted millet polyphenols and verified whether they play important roles during this process. The results showed that millet polyphenols significantly prevented H₂O₂-induced cell death of SH-SY5Y cells and decreased oxidative stress levels in cells. In addition, the expression levels of pro-inflammatory factors and AD-related genes were also downregulated by treatment with millet polyphenols. The above results indicated that millet and millet polyphenols could exert neural protective effects under high fat diet-induced oxidative stress by upregulating the expression of antioxidant enzymes and downregulating the expression of AD-related genes.

Lactobacillus plantarum FRT10 alleviated high-fat diet-induced obesity in mice through regulating the PPARα signal pathway and gut microbiota

Previous studies showed that probiotics supplementation contributed to alleviate obesity. This work was to assess the efficacy of Lactobacillus plantarum FRT10 from sour dough in alleviating obesity in mice fed with a high-fat diet (HFD), and the underlying mechanisms focusing on modulation of the gut microbiota profile. Kunming mice were fed with a regular diet (CT), a high-fat diet (HFD), and two HFDs containing low and high doses of L. plantarum FRT10 for 8 weeks. The physiological and biochemical modulations in liver were analyzed. Cecal contents were analyzed by high-throughput 16S ribosomal RNA sequencing. FRT10 supplementation significantly reduced body weight gain, fat weight, and liver triacylglycerols (TGs) and alanine aminotransferase (ALT) concentrations (P < 0.05). FRT10 significantly ameliorated the HFD-induced gut dysbiosis, as evidenced by increased abundance of microbes, including Butyricicoccus, Butyricimonas, Intestinimonas, Odoribacter, and Alistipes, and decreased abundance of Desulfovibrionaceae, Roseburia, and Lachnoclostridium. Lactobacillus, Bifidobacterium, and Akkermansia were markedly increased after FRT10 intervention. In addition, real-time quantitative PCR revealed that FRT10 upregulated the mRNA expression levels of peroxisome proliferator-activated receptor-α (PPARα) and carnitine palmitoyltransferase-1α (CPT1α), and downregulated the mRNA expression levels of sterol regulatory element-binding protein 1 (SREBP-1) and TG-synthesizing enzyme diacylglycerol acyltransferase 1 (DGAT1) in liver. These findings suggested that FRT10 had anti-obesity effects in obese mice partly related to the activation of PPARα/CPT1α pathway. FRT10 can be considered a single probiotic agent for preventing HFD-induced obesity in humans and animals.

Improvement on metabolic syndrome in high fat diet-induced obese mice through modulation of gut microbiota by sangguayin decoction

ETHNOPHARMACOLOGICAL RELEVANCE

Our previous research found that Sangguayin (SGY) deccoction made by four dietary and medicinal plant components (Leaf of Morus alba L., Root of Pueraria lobata (Willd.) Ohwi., Root of Dioscorea opposita Thunb. and Fruit of Momordica charantia L.) showed significant anti-diabetic effects on db/db mice and high fat diet induced obese mice. Nevertheless, it remained unclear what the role of gut microbiota in the hypoglycaemia effects of SGY.

AIMS OF THE STUDY

This study aimed to examine the beneficial effects of Sangguayin Deccoction against metabolic syndrome and and its regulating role in gut microbiota and hepatic metabolome.

MATERIALS AND METHODS

C57BL/6J mice were divided to a normal chow diet (NCD), high-fat diet (HFD), and high-fat diet with Sangguayin Decoction (HFD-SGY, oral dose of 250 mg/kg/d) for 16 weeks. Next generation sequencing was applied for analyzing the gut microbial community of colonic contents. Further, untargeted metabolomic analysis based on LC-MS was used for determining the changes of hepatic metabolites. Hepatic genes expression were measured by quantitative PCR.

RESULTS

SGY supplement decreased blood glucose level and glucose intolerance. Illumina MiSeq sequencing revealed that SGY increased Verrucomicrobia phylum, resulting in a bloom of Akkermansia, and eventually upregulated the contents of Lachoclostridium and Roseburia. Additionally, dietary SGY decreased bacteria including Faecalibaculum, and Blautia. Moreover, the hepatic lipid metabolism was notably altered by SGY treatment. The oxidation of glutamione metabolism idecreasees, production of poly-unsaturated fatty acid (PUFA) got significant increase in liver tissue. The reversion of PUFA metabolism by SGY may act through PPARα mediated Fads1 and Fads2 gene expression. The altered metabolites in liver showed intimate correlatship with modified genera.

CONCLUSION

Data indicated that SGY reshaped gut microbial structure and improved PUFA metabolism. These functions of SGY may alter hepatic lipid metabolism, conferring preventative effects against high-fat diet induced metabolic syndrome.

Phytochemical Profile, Bioactivity, and Prebiotic Potential of Bound Phenolics Released from Rice Bran Dietary Fiber during in Vitro Gastrointestinal Digestion and Colonic Fermentation

Whole-grain dietary fiber is rich in bound-form phenolics, and the biological activity of this special structural feature has attracted increasing attention. In this study, rice bran dietary fiber (RBDF) was subjected to in vitro gastrointestinal digestion and colonic fermentation to investigate the liberation of bound phenolics and their potential activities. Bound phenolics were released at a higher ratio during colonic fermentation (27.57%) than gastrointestinal digestion (2.68%). Nine phenolic compounds were detected from the fermentation supernatants. The released phenolics showed radical scavenging activity (DPPH and ABTS assays) and α-glucosidase inhibitory activity (IC₅₀ = 19.11 μg GAE/mL). Compared with phenolics-removed RBDF (PR-RBDF), RBDF had a significantly stronger prebiotic effect on the microbes associated with diabetes (Lactobacillus spp., Akkermansia muciniphila, and Faecalibacterium prausnitzii). These findings indicate that bound phenolics may act as important functional components that could contribute to the health benefits of whole-grain dietary fiber.

Cashew apple fiber prevents high fat diet-induced obesity in mice: an NMR metabolomic evaluation

Dietary fiber intake plays an important role in the prevention of obesity. This study aimed at investigating the effect of cashew fiber without low molecular weight compounds (CABwc) on obesity prevention and metabolomics in a murine model of diet-induced obesity. Mice were fed a chow diet (CD), a high-fat diet (HFD) or a high-fat diet supplemented with CABwc (10%) (HFD-CABwc) for 15 weeks. The body weight, abdominal fat, serum glucose levels, insulin and lipid profiles, satiety hormones such as leptin and ghrelin, digestive enzymes such as amylase and lipase, and inflammatory mediators such as TNF-α, IL-6, and adiponectin were measured, in addition to performing serum and hepatic tissue analyses. The metabolomic analysis was based on nuclear magnetic resonance (NMR) spectroscopy of serum and feces. The effects observed with ingestion of CABwc were appetite control and prevention of hyperglycemia, hyperinsulinemia and hypertriglyceridemia, as well as the prevention of the inflammatory process and reduction of liver injury caused by the HFD. In addition, NMR evidenced the presence of SCFAs in serum and feces of mice fed with HFD-CABwc. These findings suggest that CABwc promoted satiety in mice, improving the metabolism of glucose and lipids. Positive effects of obesity prevention may be associated with SCFA production.

Probiotic mechanisms of action

Intestinal dysbiosis is associated with a large number of disease processes including necrotizing enterocolitis and late-onset sepsis in preterm infants and colic and antibiotic-associated diarrhea in term infants. Probiotic microbes are increasingly administered to infants with the intent of decreasing risk of these acute diseases as well as chronic diseases of childhood such as asthma and atopic disease. The mechanisms by which probiotics decrease inflammation, decrease intestinal permeability, alter the intestinal microbiota, and influence metabolism have been discovered through both in vitro studies and in vivo in animal models. We review key mechanisms by which probiotic microbes improve health with emphasis on recent discoveries in the field.

Prebiotic attenuation of olanzapine-induced weight gain in rats: analysis of central and peripheral biomarkers and gut microbiota

Olanzapine is an effective antipsychotic drug but since it causes significant weight gain, it is not well tolerated by psychosis patients. The prebiotic, B-GOS^®, attenuates metabolic dysfunction in obese subjects, and in rodents, alters central NMDA receptors and may affect serotonin receptors that are relevant in psychosis. We have determined whether B-GOS^® influenced olanzapine-associated weight gain and central NMDA and serotonin receptors. Circulating acetate, IL-1β, IL-8 and TNFα, liver acetyl-CoA carboxylase (ACC), white adipose tissue (WAT) acetate receptor GPR43, and specific faecal bacteria genera were also measured to provide mechanistic information. Adult female Sprague-Dawley rats were administered a B-GOS^® (0.5 g/kg/day) solution or water for 21 days, and received a single, daily, intraperitoneal injection of olanzapine or saline on days 8-21. The intake of B-GOS^® significantly attenuated olanzapine-induced weight gain without altering frontal cortex 5-HT2AR blockade. Cortical GluN1 levels were elevated by olanzapine in the presence of B-GOS^®. Plasma acetate concentrations increased following B-GOS^® or olanzapine administration alone, but reduced when prebiotic and drug were administered in combination. This pattern was paralleled by hepatic ACC mRNA expression. The abundance of WAT GPR43 mRNA was reduced by olanzapine, only in the absence of B-GOS^®. Co-administration of B-GOS^® and olanzapine also elevated plasma TNFα, which is reported to influence lipid metabolism. Finally, B-GOS^® elevated faecal Bifidobacterium spp. and reduced some bacteria in the Firmicutes phylum, whilst olanzapine treatment either alone or with B-GOS^®, was without effect. These data suggest that inclusion of B-GOS^® as an adjunct to olanzapine treatment in schizophrenia may prevent weight gain and have benefits on cognitive function in psychosis. The role of acetate in these effects requires further investigation.

Whole cereal grains and potential health effects: Involvement of the gut microbiota

The intakes of whole cereal grains (WCGs) have long been linked to decreased risks of metabolic syndromes (MetS) and several chronic diseases. Owing to the complex range of components of cereals, which may show synergistic activities to mediate these protective effects, the mechanisms by which the benefits of whole cereals arise are not fully understood. The gut microbiota has recently become a new focus of research at the intersection of diet and metabolic health. Moreover, cereals contain various ingredients known as microbiota-accessible substrates that resist digestion in the upper gastrointestinal tract, including resistant starch and non-starch polysaccharides such as β-glucan and arabinoxylans, making them an important fuel for the microbiota. Thus, WCGs may manipulate the ecophysiology of gut microbiota. In this review, the scientific evidence supporting the hypothesis that WCGs prevent MetS by modulating gut microbiota composition and functions are discussed, with focuses on cereal intake-related mechanisms by which gut microbiota contributes to human health and scientific evidences for the effects of WCGs on modulating gut microbiota. Once strong support for the association among WCGs, gut microbiota and host metabolic health can be demonstrated, particular cereals, their processing technologies, or cereal-based foods might be better utilized to prevent and possibly even treat metabolic disease.