Obesity, Motility, Diet, and Intestinal Microbiota-Connecting the Dots

Unraveling colorectal cancer prevention: The vitamin D - gut flora - immune system nexus

Colorectal cancer (CRC) is one of the most common cancers diagnosed in the world. Although environmental and genetic factors play a major role in the pathogenesis of CRC, extensive research has suggested that vitamin D may play a pivotal role in the development of CRC. Vitamin D, primarily obtained through sunlight exposure, dietary sources, and supplements, has long been recognized for its essential functions in maintaining health, including immune regulation. This article delves into the intricate relationship between vitamin D, the immune system, gut flora, and the prevention of CRC. It presents a synthesis of epidemiological data, experimental studies, and clinical trials, highlighting the mechanisms by which vitamin D influences immune cell function, cytokine production, and inflammation. By enhancing the immune system’s surveillance and anti-tumor activity, vitamin D may offer a promising avenue for CRC prevention. Furthermore, this comprehensive review delves into the prospective clinical applications of vitamin D supplementation and delineates the forthcoming avenues of research in this dynamic domain. Additionally, the paper tentatively outlines a spectrum of prophylactic impacts of vitamin D on CRC, emphasizing its significant potential in reducing CRC risk through shedding light on its mechanisms, encompassing antineoplastic mechanisms, influences on the immune system, and modulation of the gut microbiome.

Unraveling colorectal cancer prevention: The vitamin D - gut flora - immune system nexus

Colorectal cancer (CRC) is one of the most common cancers diagnosed in the world. Although environmental and genetic factors play a major role in the pathogenesis of CRC, extensive research has suggested that vitamin D may play a pivotal role in the development of CRC. Vitamin D, primarily obtained through sunlight exposure, dietary sources, and supplements, has long been recognized for its essential functions in maintaining health, including immune regulation. This article delves into the intricate relationship between vitamin D, the immune system, gut flora, and the prevention of CRC. It presents a synthesis of epidemiological data, experimental studies, and clinical trials, highlighting the mechanisms by which vitamin D influences immune cell function, cytokine production, and inflammation. By enhancing the immune system's surveillance and anti-tumor activity, vitamin D may offer a promising avenue for CRC prevention. Furthermore, this comprehensive review delves into the prospective clinical applications of vitamin D supplementation and delineates the forthcoming avenues of research in this dynamic domain. Additionally, the paper tentatively outlines a spectrum of prophylactic impacts of vitamin D on CRC, emphasizing its significant potential in reducing CRC risk through shedding light on its mechanisms, encompassing antineoplastic mechanisms, influences on the immune system, and modulation of the gut microbiome.

Alterations in gastric and gut microbiota following sleeve gastrectomy in high-fat diet-induced obese rats

Obesity is considered a high-risk disease and a global epidemic, and the number of obese patients is rising at an alarming rate worldwide. High-fat diet-induced dysbiosis of the intestinal microbiota is considered an essential factor related to obesity. Bariatric surgery induces a sharp decrease in fat content and effectively improves the metabolism of obese individuals. Herein, we aimed to investigate the effects of a high-fat diet-induced obesity and the alterations in gastric and intestinal microbiota resulting from sleeve gastrectomy on clinical outcomes. We performed 16S sequencing of gastric and fecal samples obtained from rats in three treatment groups: normal chow diet, high-fat diet (HFD), and sleeve gastrectomy after HDF for 14 weeks. The area under the curve of fasting glucose and the levels of leptin and low-density lipoproteins were significantly different between groups. Microbial taxa that were highly correlated with several clinical parameters were identified for each group. Glyoxylate and dicarboxylate, taurine and hypotaurine, butanoate, nitrogen, and pyrimidine metabolism and aminoacyl-transfer ribonucleic acid biosynthesis were affected by bariatric surgery and were significantly associated with changes in the composition of gastric and fecal microbiomes. Connectivity and co-occurrence were higher in fecal samples than in gastric tissues. Our results elucidated the positive effects of sleeve gastrectomy in obesity and shed light on changes in the microbiomes of gastric and fecal samples.

Short chain fatty acids and GIT hormones mitigate gut barrier disruption in high fat diet fed rats supplemented by synbiotics

High fat diet (HFD) predisposes to many metabolic changes; it may disrupt gut barrier integrity and gut microbiota composition. Synbiotic supplementation may promote host’s metabolic health by selective activation of the healthy microorganisms. This study aimed to probe the interaction between synbiotic supplementation, gut microbiota and gut hormones in HFD states. Twenty-seven adult male albino rats, 3 groups, group I: control, group II: HFD received HFD for 12 weeks and group III: synbiotic-supplemented HFD received synbiotic in the last 6 weeks. The anthropometric measurments were measured. Liver transaminases, lipid profile, parameters of insulin resistance, serum serotonin, glucagon like polypeptide-1 (GLP-1), oxidant/antioxidant markers (MDA/GPx), zonulin levels and quantitative cecal short chain fatty acids (SCFA) were assessed. Samples of liver and colon were employed for histopathological studies. Compared to HFD group, synbiotic led to a significant reduction in anthropometric measurements, liver enzymes, atherogenic index, HOMA-IR and MDA denoting improved dyslipidemia, insulin resistance and oxidative state. Moreover, synbiotic supplementation decreased serum zonulin and increased both serum serotonin, GLP-1 and cecal SCFAs. Synbiotic supplementation ameliorated the metabolic derangements and the disturbed integrity of the intestinal barrier induced by HFD. As synbiotics can increase gut hormones (serum GLP-1&serotonin) and SCFAs.

The magnitude of oral rehydration salt utilization in diarrhea hot spot regions of Ethiopia and its associated factors among under-five children: A multilevel analysis based on Bayesian approach

Background

Diarrhea leads the children to severe dehydration or death as a result of the loss of water and electrolytes (namely, potassium, chloride, sodium, and bicarbonate). To compensate for the losses, ORS is given to children who experienced diarrhea.

Objective

To estimate the magnitude of ORS utilization in diarrhea hotspot regions of Ethiopia and to assess its associated factors among under-five children.

Methods

To conduct this study, we used the 2016 Ethiopian demographic and health survey data. A total of 1,079 weighted sample children were selected. Each sample was selected randomly. Then, to identify factors associated with ORS utilization in diarrhea hotspot regions of Ethiopia, a multilevel analysis based on the Bayesian approach was applied. Finally, the credible interval of AOR that does not include 1 was considered statistically significant.

Results

The magnitude of ORS utilization for children in diarrhea hotspot regions of Ethiopia was 28%. Being urban resident (AOR = 1.92; 95% CrI: 1.13-3.3), woman household head (AOR = 2.11; 95% CrI: 1.3-3.9), having higher educational level (AOR = 1.52; 95% CrI: 1.04-2.22), member of health insurance (AOR = 1.73; 95% CrI: 1.14-2.43), and being exposed for media (AOR = 1.43; 95% CrI: 1.18-2.5) increases ORS utilization for diarrhea management.

Conclusion

Residence, educational level, health insurance, and media exposure were the factors of ORS utilization. So, to increase the practice of ORS utilization for diarrhea management in Ethiopia, the Ministry of Health and the Government of Ethiopia should consider those factors when they design diarrhea prevention and control strategies.

The Influence of Obesity on Small Bowel Capsule Endoscopy

Objective

Intestinal motility may be different in obese and nonobese patients, but this has not been determined. Here, we sought to evaluate the effect of obesity on small bowel capsule endoscopy (SBCE). Patients and Methods. We retrospectively analyzed the cases of the 340 patients who underwent SBCE for small intestinal disease (excluding cases of unobservable total small bowel, small bowel stenosis, and bowel resection) at our hospital during the period January 2014 to December 2020 to extract patient background factors and the bowel transit times of SBCE according to the presence/absence of obesity (defined as a body mass index (BMI) ≥ 25 kg/m²).

Results

The obese group was 54 patients (nonobese, n = 286). The small bowel transit time (SBTT) was significantly shorter in the obese patients compared to the nonobese patients (p = 0.0026), and when we divided the patients by their short/long SBTTs using 216.5 min as the cutoff, we observed significant between-group differences in the patients' age (≥60 years) and in the patients' hospitalization status at the time of the SBCE examination. A multivariate analysis revealed that hospitalized status at the examination is a factor contributing significantly to a long SBTT (OR 0.25, 95% CI: 0.15–0.42, p < 0.0001). An analysis using the outpatient/inpatient conditions showed that obesity was an independent factor in the inpatient status at the SBCE examination with a significant short SBTT (OR 2.91, 95% CI: 1.06–7.97, p = 0.0380). Constipation at the examination was also a factor contributing to a long SBTT (OR 0.26, 95% CI: 0.07–0.99, p = 0.0493).

Conclusion

The SBTT of the SBCE was significantly shorter in the obese patients. This tendency was especially evident in the hospitalized state.

High-fat diets on the enteric nervous system: Possible interactions and mechanisms underlying dysmotility

Obesity is a chronic disease that affects various physiological systems. Among them, the gastrointestinal tract appears to be a main target of this disease. High-fat diet (HFD) animal models can help recapitulate the classic signs of obesity and present a series of gastrointestinal alterations, mainly dysmotility. Because intestinal motility is governed by the enteric nervous system (ENS), enteric neurons, and glial cells have been studied in HFD models. Given the importance of the ENS in general gut physiology, this review aims to discuss the relationship between HFD-induced neuroplasticity and gut dysmotility observed in experimental models. Furthermore, we highlight components of the gut environment that might influence enteric neuroplasticity, including gut microbiota, enteric glio-epithelial unit, serotonin release, immune cells, and disturbances such as inflammation and oxidative stress.

What Is the Role of Gut Microbiota in Obesity Prevalence? A Few Words about Gut Microbiota and Its Association with Obesity and Related Diseases

Obesity is becoming the most dangerous lifestyle disease of our time, and its effects are already being observed in both developed and developing countries. The aim of this study was to investigate the impact of gut microbiota on the prevalence of obesity and associated morbidities, taking into consideration underlying molecular mechanisms. In addition to exploring the relationship between obesity and fecal microorganisms with their metabolites, the study also focused on the factors that would be able to stimulate growth and remodeling of microbiota. Assessed articles were carefully classified according to a predetermined criterion and were critically appraised and used as a basis for conclusions. The considered articles and reviews acknowledge that intestinal microbiota forms a multifunctional system that might significantly affect human homeostasis. It has been proved that alterations in the gut microbiota are found in obese and metabolically diseased patients. The imbalance of microbiome composition, such as changes in Bacteroidetes/Firmicutes ratio and presence of different species of genus Lactobacillus, might promote obesity and comorbidities (type 2 diabetes mellitus, hypertension, dyslipidemia, depression, obstructive sleep apnea). However, there are also studies that contradict this theory. Therefore, further well-designed studies are needed to improve the knowledge about the influence of microbiota, its metabolites, and probiotics on obesity.

Morphological alterations in gastrointestinal organs of western-diet obese rats submitted to vertical sleeve gastrectomy or Roux-en-Y gastric bypass

To assess the effect of vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) on the esophageal and intestinal morphology of western diet (WD)-obese rats and to characterize the stomach histopathology of WD rats submitted to VSG. Male Wistar rats received WD from 2-4 months of age, to induce obesity, before randomly submitting them to pseudo (WD-SHAM), VSG (WD-VSG) or RYGB (WD-RYGB) surgeries. Gastrointestinal histomorphometry was performed at 3-months post-surgery. The upper esophagus of VSG and RYGB rats increased luminal area, while reductions in the keratin layer of the mucosa and the tunica muscularis were observed only in the RYGB animals. In the lower esophagus, both surgeries increased keratin layer thickness, but reduced the mucosal mucus content, while RYGB increased the thickness of the tunica mucosa and muscularis. The glandular region of the stomach of WD-VSG rats exhibited hypotrophy, epithelial erosion, fibrosis and moderate inflammatory infiltration. VSG and RYGB increased the villi height in the ileum, and the thickness of the tunica muscularis in the jejunum and ileum of WD rats; furthermore, RYGB augmented the ileal villi height. Thus both approaches induced histomorphological alterations in the esophagus and intestine and VSG damaged the gastric mucosa, even over the long-term.

Role of microbial dysbiosis in carcinogenesis & cancer therapies

The human body supports a heterogeneous population of microorganisms. Every microorganism has the ability to contribute to the unique microenvironment around it. The aim of this review is to discuss the changes in the microbial population and their relative abundance across different ecosystems of the human body, the interactions within the microbial communities, metabolites they secrete to their external environment, their immunomodulatory functions, their signal transduction pathways and how these respond to environmental stimuli such as various diets, alcohol and drug consumption, smoking and finally suggest new therapeutic approaches. The microbiota may leads to cancer through inflammation mediated mechanisms which modulate immune responses, or produce carcinogenic metabolites and genotoxins, or deregulate cell proliferative signalling pathways. The identification of these molecular mechanisms in carcinogenesis may lead to better treatment strategies. In this review we have tried to explore the changes in microbial composition between cancer and normal tissues and what molecular mechanisms provide a connecting link between microbial dysbiosis and cancer.

Differential Toxicological Outcome of Corn Oil Exposure in Rats and Mice as Assessed by Microbial Composition, Epithelial Permeability, and Ileal Mucosa-Associated Immune Status

Studies to evaluate the toxicity of xenobiotics on the human gut microbiome and related health effects require a diligent selection of (1) an appropriate animal model to facilitate toxicity assessment in predicting human exposure, and (2) an appropriate non-interfering vehicle for the administration of water insoluble compounds. In biomedical studies with water insoluble xenobiotics, corn oil is one of the most commonly used nonaqueous vehicles. This study evaluated the suitability of corn oil as a vehicle in adult female Sprague Dawley rats and adult CD-1 mice; the rodent models that are often utilized in toxicological studies. We studied the host response in terms of change in the intestinal microbiome and mRNA expression of intestinal permeability and immune response-related genes when water (control) and corn oil (2 ml/kg) were administered as a vehicle through oral gavage. The results showed that the use of corn oil as a vehicle has no adverse impact in rats for either the immune response or the intestinal microbial population. On the other hand, mice treated with corn oil showed changes in bacterial community adhered to the ileum, as well as changes in the mRNA expression of intestinal permeability-related and ileal mucosa-associated immune response genes. Overall, results of this study suggest that the type of rodent species and vehicle used in toxicological risk assessments of xenobiotics studies should be taken into consideration in the experimental setup and study design.

Trends and determinants of diarrhea among under-five children in Ethiopia: cross-sectional study: multivariate decomposition and multilevel analysis based on Bayesian approach evidenced by EDHS 2000-2016 data

Background

Despite significant progress in the reduction of under-five child deaths over the last decades in Ethiopia, still diarrhea remains the second cause of morbidity and mortality among under five children next to pneumonia.

Objective

To show trends and determinants of diarrhea among under five children in Ethiopia based on the four Ethiopian Demographic and health surveys data (2000–2016).

Methods

A total of 10,753 in 2000, 10,039 in 2005, 10,946 in 2011 and 10,337 in 2016 under five age children were involved in this study. Multivariate decomposition and multilevel analysis based on Bayesian approach was performed.

Results

Ninety seven percent of the change in diarrhea prevalence over time was attributable to difference in behavior. Being twin (AOR = 1.3; 95% CrI 1.1–1.5), big weight (AOR = 1.63; 95% CrI 1.62–2.02), not vaccinated for rotavirus (AOR = 1.44; 95% CrI 1.12–1.9) and for measles (AOR = 1.2; 95% CrI 1.1–1.33), poor wealth status (AOR 2.6; 95% CrI 1.7–4.06), having more than three under-five children (AOR 1.3; 95% CrI 1.1–1.61), member of health insurance (AOR 2.2; 95% CrI 1.3–3.8) and long distance from the health facility (AOR 2.7; 95% CrI 2.2–3.5) were more likely to experience diarrhea.

Conclusion

The prevalence of diarrhea was significantly declined over the last sixteen years and the decline was due to difference in behavior between the surveys. Being twin, weight of child at birth, vaccinated for measles and rotavirus, number of under-five children, wealth status, distance to health facility, health insurance and child waste disposal method were significantly associated with diarrhea among under five children in Ethiopia. Therefore Ethiopian government should focus on the strengthening and scaling up of behavioral change packages of the community regarding to keeping hygiene and sanitation of the community and their environment, vaccinating their children, accessing health care services to prevent diarrheal disease.

Probiotics as a therapeutic strategy in obesity and overweight: a systematic review

Obesity and overweight are two of the most health challenges with an increasing prevalence in recent years, in which several complications have been identified to have a high impact in patients' health conditions. In this vein, an increasing interest in the gut microbiota has emerged as a target for therapeutic strategies in obesity and overweight due to its direct relation with the aforementioned health conditions and complications. Thus, the aim of this study was to evaluate the efficacy of probiotics as a therapeutic strategy in the management of obesity and overweight. A systematic review of randomised controlled trials was carried out in 6 databases until May 2019 to assess the use of probiotics in obesity and overweight patients. The Jadad Scale was used to assess the quality of the clinical trials. Twenty-three clinical trials published between 2000 and 2019 met the inclusion criteria. The role of probiotics in reducing body mass index and weight as well as changing the visceral abdominal fat area, waist and hip circumference were shown in 14 of 23 trials (60.87%); 14 trials (60.87%) showed changes on patients' fatty acids and biomarkers; and 4 trials (17.39%) studied the role of the gut microbiota in obese and overweight patients. Some probiotics strains are shown to be effective in reducing body mass index and hip circumference. This review provides evidence of successful results in weight loss using probiotic groups.

Lifestyle, psychological stress, and incidence of adolescent constipation: results from the Toyama birth cohort study

Background

We aimed to clarify the predisposing factors for adolescent constipation in a longitudinal study, because while factors associated with childhood constipation have been reported, prospective studies on the incidence of constipation are lacking.

Methods

We enrolled 5540 adolescents aged 12 to 13 years from the Toyama Birth Cohort Study—a community-based prospective study examining children’s health. The incidence of constipation, defined as bowel movement frequency of less than once every 2 days, was surveyed during the three-year period from baseline (grade 4) to follow-up (grade 7). Multivariate logistic regression analyses were performed to explore the association between the incidence of adolescent constipation and their lifestyle variables.

Results

A total of 261 adolescents (4.7%) developed constipation during the three-year period. Female sex (odds ratio [OR] = 2.62,) overweight (OR = 0.60), and infrequent intake of fruits (OR = 1.50) at baseline were associated with the incidence of constipation. Furthermore, factors related to lifestyle changes and psychological status such as skipping breakfast (OR = 1.73), becoming physically inactive (OR = 1.55), and being persistently irritated (OR = 1.80) were significantly associated with the incidence of constipation.

Conclusion

Our prospective study demonstrated that female sex, insufficient fruit intake, and deteriorating lifestyles such as skipping breakfast and becoming inactive during the 3-year period were associated with the incidence of adolescent constipation. Beyond anecdotal, maintaining a healthy lifestyle is recommended to reduce the incidence of adolescent constipation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-020-10044-5.

Enhanced thermal stability of green banana starch by heat-moisture treatment and its ability to reduce body fat accumulation and modulate gut microbiota

The physicochemical properties (including morphology, pasting, and thermal properties) of resistant starch (RS) in green banana starch were analyzed after the heat-moisture treatment in the presence of citric acid (CAHMT) at different temperatures. Moreover, this study evaluated whether the administration of CAHMT banana starch could reduce body fat accumulation and modulate gut microbiota. Our results demonstrated that the CAHMT process (90 °C) resulted in a higher retention (80.9%) and thermal stability of RS, alteration in the crystalline structure of starch from B-type to A-type, and increased solubility (27.9-fold) and gelatinization temperatures (from 66.26-78.89 °C to 81.48-92.11 °C). A reduction in swelling power (-57.7%) and a loss of pasting viscosity were also noted. Even after a 30 min boil, the retention rate of residual RS (CAHMT at 90 °C) was up to 50% (4.3-fold higher than the control). Rats fed the CAHMT banana starch resulted in significantly (p < 0.05) lower total visceral fat (-18.1%) and Firmicutes to Bacteroidetes ratio as well as higher total fecal short chain fatty acids. The CAHMT process at 90 °C enhanced the thermal stability of banana RS allowing a wider range of applications in functional foods.

Diet in neurogenic bowel management: A viewpoint on spinal cord injury

The aim of this review is to offer dietary advice for individuals with spinal cord injury (SCI) and neurogenic bowel dysfunction. With this in mind, we consider health conditions that are dependent on the level of lesion including skeletal muscle atrophy, autonomic dysreflexia and neurogenic bladder. In addition, SCI is often associated with a sedentary lifestyle, which increases risk for osteoporosis and diseases associated with chronic low-grade inflammation, including cardiovascular and chronic kidney diseases. The Mediterranean diet, along with exercise and dietary supplements, has been suggested as an anti-inflammatory intervention in individuals with SCI. However, individuals with chronic SCI have a daily intake of whole fruit, vegetables and whole grains lower than the recommended dietary allowance for the general population. Some studies have reported an increase in neurogenic bowel dysfunction symptoms after high fiber intake; therefore, this finding could explain the low consumption of plant foods. Low consumption of fibre induces dysbiosis, which is associated with both endotoxemia and inflammation. Dysbiosis can be reduced by exercise and diet in individuals with SCI. Therefore, to summarize our viewpoint, we developed a Mediterranean diet-based diet and exercise pyramid to integrate nutritional recommendations and exercise guidelines. Nutritional guidelines come from previously suggested recommendations for military veterans with disabilities and individuals with SCI, chronic kidney diseases, chronic pain and irritable bowel syndrome. We also considered the recent exercise guidelines and position stands for adults with SCI to improve muscle strength, flexibility and cardiorespiratory fitness and to obtain cardiometabolic benefits. Finally, dietary advice for Paralympic athletes is suggested.

Metabolic and gut microbiome changes following GLP-1 or dual GLP-1/GLP-2 receptor agonist treatment in diet-induced obese mice

Enteroendocrine L-cell derived peptide hormones, notably glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2), have become important targets in the treatment of type 2 diabetes, obesity and intestinal diseases. As gut microbial imbalances and maladaptive host responses have been implicated in the pathology of obesity and diabetes, this study aimed to determine the effects of pharmacologically stimulated GLP-1 and GLP-2 receptor function on the gut microbiome composition in diet-induced obese (DIO) mice. DIO mice received treatment with a selective GLP-1 receptor agonist (liraglutide, 0.2 mg/kg, BID) or dual GLP-1/GLP-2 receptor agonist (GUB09–145, 0.04 mg/kg, BID) for 4 weeks. Both compounds suppressed caloric intake, promoted a marked weight loss, improved glucose tolerance and reduced plasma cholesterol levels. 16S rDNA sequencing and deep-sequencing shotgun metagenomics was applied for comprehensive within-subject profiling of changes in gut microbiome signatures. Compared to baseline, DIO mice assumed phylogenetically similar gut bacterial compositional changes following liraglutide and GUB09-145 treatment, characterized by discrete shifts in low-abundant species and related bacterial metabolic pathways. The microbiome alterations may potentially associate to the converging biological actions of GLP-1 and GLP-2 receptor signaling on caloric intake, glucose metabolism and lipid handling.

Correlation Analysis of Intestinal Redox State with the Gut Microbiota Reveals the Positive Intervention of Tea Polyphenols on Hyperlipidemia in High Fat Diet Fed Mice

Tea polyphenols (TP) possess the ability to regulate dyslipidemia and gut microbiota dysbiosis. However, the underlying mechanism is still elusive. The present study explored the intervention of TP on high fat diet induced metabolic disorders, gut microbiota dysbiosis in mice, and the underlying intestinal mechanism. As a result, TP significantly ameliorated hyperlipidemia, improved the expression levels of hepatic lipid metabolism genes, and modulated gut microbiota. The underlying mechanism was supposed to rely on the maintaining of intestinal redox state by TP. Intestinal redox related indicators were significantly correlated with the distribution of gut microbiota. An unidentified genus of Lachnospiraceae, Bacteroides, Alistipes, and Faecalibaculum were identified as the biomarkers for intestinal redox state. Importantly, different dosages of TP modulated intestinal redox state and gut microbiota in varied patterns, and an overdose intake attenuated the beneficial effects on gut health. Our findings offered novel insights into the mechanism of TP on intestinal homeostasis.