Pulse Crop Effects on Gut Microbial Populations, Intestinal Function, and Adiposity in a Mouse Model of Diet-Induced Obesity

Tree peony seed oil alleviates hyperlipidemia and hyperglycemia by modulating gut microbiota and metabolites in high-fat diet mice

With the changes of people's lifestyle, hyperlipidemia and hyperglycemia which were induced from a diet high in both fat and sugar have become serious health concerns. Tree peony seed oil (PSO) is a novel kind of edible oil that shows great potential in the food industry because of its high constituent of unsaturated fatty acids. Based 16S rRNA and gut untargeted metabolomics, this study elucidated that the mechanism of PSO regulating blood glucose (Glu) and lipids. The impact of PSO on gut microbiota balance and gut metabolites of mice with a high-fat diet (HFD) was evaluated. The findings indicated that PSO decreased HFD mice's body weight and fat accumulation, ameliorating the levels of blood lipid, reduced liver fat vacuole levels. What's more PSO modulated the proportion of gut microbiota in HFD mice and enhanced the abundance of probiotics. Furthermore, untargeted metabolomic analysis revealed that PSO not only impacted the generation of short-chain fatty acids (SCFAs) by gut microorganism and altered metabolic pathway but exerted influence on secondary bile acids (BA), amino acid metabolism, and various other metabolites. These results suggested that PSO has the potential function for mitigating HFD-induced hyperlipidemia and hyperglycemia by regulating gut microbiota and host metabolism.

Ingestion of Bean Leaves Reduces Metabolic Complications and Restores Intestinal Integrity in C57BL/6 Mice with Obesity Induced by a High-Fat and High-Fructose Diet

Consumption of foods with fiber and compounds can promote gastrointestinal health and reduce obesity complications. Therefore, treatment with common bean leaves (BL) against obesity was evaluated in mice with a high-fat and high-fructose diet (HFFD) for 14 weeks. The bromatological and phytochemical characterization of BL were determined. Afterwards, the animals were supplemented with BL (10%) or a standard diet (SD) as a strategy to encourage a healthy diet for 12 additional weeks. Changes in body composition, lipid profile, and intestinal integrity were analyzed. The characterization of BL stood out for its content of 27.2% dietary fiber, total phenolics (475.04 mg/100 g), and saponins (2.2 mg/100 g). The visceral adipose tissue (VAT) decreased in the BL group by 52% compared to the HFFD group. Additionally, triglyceride levels were 23% lower in the BL consumption group compared to the HFFD group. The improvement in lipid profile was attributed to the 1.77-fold higher fecal lipid excretion in the BL consumption group compared to the HFFD group and the inhibition of pancreatic lipase by 29%. Furthermore, BL supplementation reduced the serum levels of IL-6 (4.4-fold) and FITC-dextran by 50% compared with those in the HFFD group. Metabolic endotoxemia was inhibited after BL supplementation (-33%) compared to the HFFD group. BL consumption as a treatment in obese mice reduces adipose tissue accumulation and improves the lipid profile. Furthermore, we report for the first time that BL consumption improves intestinal integrity.

Dietary pulses as a means to improve the gut microbiome, inflammation, and appetite control in obesity

A dysbiotic intestinal microbiome has been linked to chronic diseases such as obesity, which may suggest that interventions that target the microbiome may be useful in treating obesity and its complications. Appetite dysregulation and chronic systemic low-grade inflammation, such as that observed in obesity, are possibly linked with the intestinal microbiome and are potential therapeutic targets for the treatment of obesity via the microbiome. Dietary pulses (e.g., common beans) are composed of nutrients and compounds that possess the potential to modulate the gut microbiota composition and function which can in turn improve appetite regulation and chronic inflammation in obesity. This narrative review summarizes the current state of knowledge regarding the connection between the gut microbiome and obesity, appetite regulation, and systemic and adipose tissue inflammation. More specifically, it highlights the efficacy of interventions employing dietary common beans as a means to improve gut microbiota composition and/or function, appetite regulation, and inflammation in both rodent obesity and in humans. Collectively, results presented and discussed herein provide insight on the gaps in knowledge necessary for a comprehensive understanding of the potential of beans as a treatment for obesity while highlighting what further research is required to gain this understanding.

Plant Proteins: Methods of Quality Assessment and the Human Health Benefits of Pulses

As countries increase their standard of living and individual income levels rise, there is a concomitant increase in the demand for animal-based protein. However, there are alternative sources. One of the alternatives available is that of increased direct human consumption of plant proteins. The quality of a dietary protein is an important consideration when discussing the merits of one protein source over another. The three most commonly used methods to express protein quality are the protein efficiency ratio (PER), a weight gain measurement; protein digestibility-corrected amino acid score (PDCAAS); and the digestible indispensable amino acid score (DIAAS). The possibility that alterations in the quality and quantity of protein in the diet could generate specific health outcomes is one being actively researched. Plant-based proteins may have additional beneficial properties for human health when compared to animal protein sources, including reductions in risk factors for cardiovascular disease and contributions to increased satiety. In this paper, the methods for the determination of protein quality and the potential beneficial qualities of plant proteins to human health will be described.

Chemopreventive Effect of Cooked Chickpea on Colon Carcinogenesis Evolution in AOM/DSS-Induced Balb/c Mice

Chickpeas are one of the most widely consumed legumes worldwide and they might prevent diseases such as cancer. Therefore, this study evaluates the chemopreventive effect of chickpea (Cicer arietinum L.) on the evolution of colon carcinogenesis induced with azoxymethane (AOM) and dextran sodium sulfate (DSS) in a mice model at 1, 7, and 14 weeks after induction. Accordingly, the expression of biomarkers-such as argyrophilic nucleolar organizing regions (AgNOR), cell proliferation nuclear antigen (PCNA), β-catenin, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2)-was assessed in the colon of BALB/c mice fed diets supplemented with 10 and 20% cooked chickpea (CC). The results showed that a 20% CC diet significantly reduced tumors and biomarkers of proliferation and inflammation in AOM/DSS-induced colon cancer mice. Moreover, body weight loss decreased and the disease activity index (DAI) was lower than the positive control. Lastly, tumor reduction was more evident at week 7 in the groups fed a 20% CC diet. In conclusion, both diets (10% and 20% CC) exert a chemopreventive effect.

Consumption of Common Bean Suppresses the Obesogenic Increase in Adipose Depot Mass: Impact of Dose and Biological Sex

Obesity prevention is stated as a simple objective in the public health guidelines of most countries: avoid adult weight gain. However, the success of the global population in accomplishing this goal is limited as reflected in the persisting pandemic of overweight and obesity. While many intervention strategies have been proposed, most are directed at mitigating the consequences of obesity. Efforts intended to prevent unintentional weight gain and associated adiposity are termed anti-obesogenic. Herein, evidence is presented that a neglected category of foods, pulses, i.e., grain legumes, have anti-obesogenic activity. Using a preclinical mouse model of obesity, a dose-response study design in animals of both biological sexes, and cooked, freeze-dried, and milled common bean as a representative pulse, data are presented showing that the rate of body weight gain is slowed, and fat accumulation is suppressed when 70% of the dietary protein is provided from common bean. These anti-obesogenic effects are reduced at lower amounts of common bean (17.5% or 35%). The anti-obesogenic responsiveness is greater in female than in male mice. RNA sequence analysis indicates that the sex-related differences extend to gene expression patterns, particularly those related to immune regulation within adipose tissue. In addition, our findings indicate the potential value of a precision nutrition approach for human intervention studies that identify "pulse anti-obesogenic responders". A precision approach may reduce the concentration of pulses required in the diet for benefits, but candidate biomarkers of responsivity to pulse consumption remain to be determined.

Thwarting Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) with Common Bean: Dose- and Sex-Dependent Protection against Hepatic Steatosis

Hepatic steatosis signifies onset of metabolic dysfunction-associated fatty liver disease (MAFLD) caused by disrupted metabolic homeostasis compromising liver function. Regular consumption of common beans reduces the risk of metabolic impairment, but its effective dose, the impact of biological sex, and underlying mechanisms of action are unknown. We fed female and male C57BL6/J mice with obesogenic yet isocaloric diets containing 0%, 17.5%, 35%, and 70% of total dietary protein derived from cooked whole common beans. Liver tissue was collected for histopathology, lipid quantification, and RNA-seq analyses. Beans qualitatively and quantitatively diminished hepatic fat deposition at the 35% dose in female and 70% dose in male mice. Bean-induced differentially expressed genes (DEGs) most significantly mapped to hepatic steatosis and revealed dose-responsive inhibition of de novo lipogenesis markers (Acly, Acaca, Fasn, Elovl6, Scd1, etc.) and triacylglycerol biosynthesis, activation of triacylglycerol degradation, and downregulation of sterol regulatory element-binding transcription factor 1 (SREBF1) signaling. Upregulated fatty acid β-oxidation was more prominent in females, while suppression of Cd36-mediated fatty acid uptake-in males. Sex-dependent bean effects also involved DEGs patterns downstream of peroxisome proliferator-activated receptor α (PPARα) and MLX-interacting protein-like (MLXIPL). Therefore, biological sex determines amount of common bean in the diet required to prevent hepatic lipid accumulation.

Cooked Adzuki Bean Reduces High-Fat Diet-Induced Body Weight Gain, Ameliorates Inflammation, and Modulates Intestinal Homeostasis in Mice

Adzuki bean is widely consumed in East Asia. Although the positive effects of its biologically active ingredients on obesity have been confirmed, the role of whole cooked adzuki bean in preventing obesity and the relationship between the effects and gut microbiota remain unclear. Mice were fed either a low-fat diet (LFD) or high-fat diet (HFD) with or without 15% cooked adzuki bean for 12 weeks. Cooked adzuki bean significantly inhibited weight gain and hepatic steatosis, reduced high levels of serum triacylglycerol (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), and alleviated systemic inflammation and metabolic endotoxemia in mice fed a HFD. Importantly, cooked adzuki bean regulated gut microbiota composition, decreased the abundance of lipopolysaccharide (LPS)-producing bacteria (Desulfovibrionaceae,Helicobacter,and Bilophila), and HFD-dependent taxa (Deferribacteraceae, Ruminiclostridium_9, Ruminiclostridium, Mucispirillum, Oscillibacter, Enterorhabdus, Tyzzerella, Anaerotruncus, Intestinimonas, unclassified_f_Ruminococcaceae, Ruminiclostridium_5, and Ruminococcaceae), and enriched Muribaculaceae, norank_f_Muribaculaceae, Anaeroplasma, Lachnospiraceae_NK4A136_group, and Lachnospiraceae to alleviate inflammation and metabolic disorders induced by HFD. These findings provide new evidence for understanding the anti-obesity effect of cooked adzuki bean.

Prebiotic Potential of Dietary Beans and Pulses and Their Resistant Starch for Aging-Associated Gut and Metabolic Health

Dietary pulses, including dry beans, lentils, chickpeas, and dry peas, have the highest proportion of fiber among different legume cultivars and are inexpensive, easily accessible, and have a long shelf-life. The inclusion of pulses in regular dietary patterns is an easy and effective solution for achieving recommended fiber intake and maintaining a healthier gut and overall health. Dietary pulses-derived resistant starch (RS) is a relatively less explored prebiotic ingredient. Several in vitro and preclinical studies have elucidated the crucial role of RS in fostering and shaping the gut microbiota composition towards homeostasis thereby improving host metabolic health. However, in humans and aged animal models, the effect of only the cereals and tubers derived RS has been studied. In this context, this review collates literature pertaining to the beneficial effects of dietary pulses and their RS on gut microbiome-metabolome signatures in preclinical and clinical studies while contemplating their potential and prospects for better aging-associated gut health. In a nutshell, the incorporation of dietary pulses and their RS in diet fosters the growth of beneficial gut bacteria and significantly enhances the production of short-chain fatty acids in the colon.

Relandscaping the Gut Microbiota with a Whole Food: Dose–Response Effects to Common Bean

Underconsumption of dietary fiber and the milieu of chemicals with which it is associated is a health concern linked to the increasing global burden of chronic diseases. The benefits of fiber are partially attributed to modulation of the gut microbiota, whose composition and function depend on the amount and quality of microbiota-accessible substrates in the diet. However, not all types of fiber are equally accessible to the gut microbiota. Phaseolus vulgaris L., or common bean, is a food type rich in fiber as well as other prebiotics posing a great potential to positively impact diet-microbiota-host interactions. To elucidate the magnitude of bean’s effects on the gut microbiota, increasing doses of common bean were administered in macronutrient-matched diet formulations. The microbial communities in the ceca of female and male mice were evaluated via 16S rRNA gene sequencing. As the bean dose increased, the Bacillota:Bacteroidota ratio (formerly referred to as the Firmicutes:Bacteroidetes ratio) was reduced and α-diversity decreased, whereas the community composition was distinctly different between the diet groups according to β-diversity. These effects were more pronounced in female mice compared to male mice. Compositional analyses identified a dose-responsive bean-induced shift in microbial composition. With an increasing bean dose, Rikenellaceae, Bacteroides, and RF39, which are associated with health benefits, were enhanced. More taxa, however, were suppressed, among which were Allobaculum, Oscillospira, Dorea, and Ruminococcus, which are predominantly associated with chronic disease risk. Investigation of the origins of the dose dependent and biological sex differences in response to common bean consumption may provide insights into bean-gut microbiota-host interactions important to developing food-based precision approaches to chronic disease prevention and control.

Compositional Changes of the High-Fat Diet-Induced Gut Microbiota upon Consumption of Common Pulses

The gut microbiome is involved in the host's metabolism, development, and immunity, which translates to measurable impacts on disease risk and overall health. Emerging evidence supports pulses, i.e., grain legumes, as underutilized nutrient-dense, culinarily versatile, and sustainable staple foods that promote health benefits through modulating the gut microbiota. Herein, the effects of pulse consumption on microbial composition in the cecal content of mice were assessed. Male mice were fed an obesogenic diet formulation with or without 35% of the protein component comprised by each of four commonly consumed pulses-lentil (Lens culinaris L.), chickpea (Cicer arietinum L.), common bean (Phaseolus vulgaris L.), or dry pea (Pisum sativum L.). Mice consuming pulses had distinct microbial communities from animals on the pulse-free diet, as evidenced by β-diversity ordinations. At the phylum level, animals consuming pulses showed an increase in Bacteroidetes and decreases in Proteobacteria and Firmicutes. Furthermore, α-diversity was significantly higher in pulse-fed animals. An ecosystem of the common bacteria that were enhanced, suppressed, or unaffected by most of the pulses was identified. These compositional changes are accompanied by shifts in predicted metagenome functions and are concurrent with previously reported anti-obesogenic physiologic outcomes, suggestive of microbiota-associated benefits of pulse consumption.

Navy Bean Supplementation in Established High-Fat Diet-Induced Obesity Attenuates the Severity of the Obese Inflammatory Phenotype

Cooked common beans (Phaseolus vulgaris) improve intestinal health in lean mice and attenuate intestinal dysbiosis and inflammation when consumed concurrent with obesity development. We determined the effects of a high-fat (HF) bean supplemented diet in mice with established obesity (induced by 12 weeks of HF diet (60% fat as kcal)) compared to obese mice consuming a HF or low-fat (LF) weight loss control diet. Obese C57BL/6 male mice remained consuming HF for eight weeks or were randomly switched from HF to an isocaloric HF with 15.7% cooked navy bean powder diet (HF→HFB) or LF (11% fat as kcal; HF→LF) (n = 12/group). HF→HFB improved the obese phenotype, including (i) fecal microbiome (increased Prevotella, Akkermansia muciniphila, and short-chain fatty acid levels), (ii) intestinal health (increased ZO-1, claudin-2, Muc2, Relmβ, and Reg3γ expression), and (iii) reduced adipose tissue (AT) inflammatory proteins (NFκBp65, STAT3, IL-6, MCP-1, and MIP-1α), versus HF (p < 0.05). Conversely, HF→LF reduced body weight and circulating hormones (leptin, resistin, and PAI-1) versus HF and HF→HFB (p < 0.05); however, AT inflammation and intestinal health markers were not improved to the same degree as HF→HFB (p < 0.05). Despite remaining on a HF obesogenic diet, introducing beans in established obesity improved the obese phenotype (intestinal health and adipose inflammation) more substantially than weight loss alone.

Plasma and Urine Metabolite Profiles Impacted by Increased Dietary Navy Bean Intake in Colorectal Cancer Survivors: A Randomized-Controlled Trial

Navy beans contain bioactive phytochemicals with colon cancer prevention properties as demonstrated in carcinogen-induced animal models. Human studies support that dietary navy bean intake modulates metabolism by the gut microbiome. This study investigated the effect of navy bean ingestion on plasma and urine metabolite profiles of overweight and obese colorectal cancer survivors. Twenty participants completed a single-blinded, randomized-controlled dietary intervention with precooked navy beans (35 g bean powder/day) or control (0 g/day) for 4 weeks. Plasma and urine were collected at baseline, 2 weeks, and 4 weeks following consumption. Nontargeted metabolomics was applied to study meals and snacks, navy beans, plasma, and urine. Increased navy bean consumption was hypothesized to (i) delineate dietary biomarkers and (ii) promote metabolic shifts relevant for cancer protection in the plasma and urine metabolome. At 4 weeks, 16 plasma and 16 urine metabolites were significantly different in the navy bean intervention group compared with placebo control (P < 0.05). Increased plasma 2,3-dihydroxy-2-methylbutyrate (1.34-fold), S-methylcysteine (1.92-fold), and pipecolate (3.89-fold), and urine S-adenosylhomocysteine (2.09-fold) and cysteine (1.60-fold) represent metabolites with cancer-protective actions following navy bean consumption. Diet-derived metabolites were detected in plasma or urine and confirmed for presence in the navy bean intervention meals and snacks. These included 3-(4-hydroxyphenyl)propionate, betaine, pipecolate, S-methylcysteine, choline, eicosapentaenoate (20:5n3), benzoate, S-adenosylhomocysteine, N-delta-acetylornithine, cysteine, 3-(4-hydroxyphenyl)lactate, gentisate, hippurate, 4-hydroxyhippurate, and salicylate. The navy bean dietary intervention for 4 weeks showed changes to pathways of metabolic importance to colorectal cancer prevention and merit continued attention for dietary modulation in future high-risk cohort investigations. PREVENTION RELEVANCE: This clinical study suggests that increased consumption of navy beans would deliver bioactive metabolites to individuals at high risk for colorectal cancer recurrence and produce metabolic shifts in plasma and urine profiles.