The Role of Carbohydrate Intake on the Gut Microbiome: A Weight of Evidence Systematic Review

Hypoglycemic, Antioxidant Activities, and Probiotic Characteristics of Lacticaseibacillus rhamnosus LBUX2302 Isolated from Stool Samples of Neonates

Lacticaseibacillus species have shown potential in managing hyperglycemia, hypercholesterolemia, and oxidative stress, depending on the strain and species. This study aimed to isolate a novel Lacticaseibacillus rhamnosus strain from healthy newborns and assess its hypoglycemic and antioxidative activity, along with other probiotic properties. A non-hemolytic L. rhamnosus LBUX2302 was isolated, and it exhibited survival rates of 2.7%, 22%, and 27.5% at pH 2, 3, and 5 for 120 min. It metabolized various carbon sources and showed resistance to gentamicin, dicloxacillin, and penicillin; coaggregated with Salmonella typhi ATCC14028, Staphylococcus aureus STCC6538, and Escherichia coli O157:H7. L. rhamnosus LBUX2302 showed hydrophobicity, autoaggregation, and adhesion to HaCat, HeLa, MCF-7, SK-LU-1, and SW620 cell lines. It also exhibited extracellular activity of bile salt hydrolase. Enzymatic inhibition assays revealed 66% and 24% inhibitions of α-amylase and α-glucosidase, respectively. Its cell-free supernatant inhibited DPPH (89%), hydroxyl (81%), and superoxide anion radicals (61%). Also, antioxidant activity was observed in whole cells and cell fragments. Finally, the presence of ferulic acid activity was detected. The results highlight L. rhamnosus LBUX2302 as a promising probiotic with hypoglycemic and antioxidant effects, warranting further in vivo evaluation for its possible inclusion in functional food and health formulations.

Diet, microbiome, and probiotics establish a crucial link in vaccine efficacy

Vaccination plays a critical role in public health by reducing the incidence and prevalence of infectious diseases. The efficacy of a vaccine has numerous determinants, which include age, sex, genetics, environment, geographic location, nutritional status, maternal antibodies, and prior exposure to pathogens. However, little is known about the role of gut microbiome in vaccine efficacy and how it can be targeted through dietary interventions to improve immunological responses. Unveiling this link is imperative, particularly in the post-pandemic world, considering impaired COVID-19 vaccine response observed in dysbiotic individuals. Therefore, this article aims to comprehensively review how diet and probiotics can modulate gut microbiome composition, which is linked to vaccine efficacy. Dietary fiber and polyphenolic compounds derived from plant-based foods improve gut microbial diversity and vaccine efficacy by promoting the growth of short-chain fatty acids-producing microbes. On the other hand, animal-based foods have mixed effects - whey protein and fish oil promote gut eubiosis and vaccine efficacy. In contrast, lard and red meat have adverse effects. Studies further indicate that probiotic supplements exert varied effects, mostly strain and dosage-specific. Interlinking diet, microbiome, probiotics, and vaccines will reveal opportunities for newer research on diet-induced microbiome-manipulated precision vaccination strategies against infectious diseases.

Effects of Supplementation with Microalgae Extract from Tetradesmus obliquus Strain Mi175.B1.a on Gastrointestinal Symptoms and Mental Health in Healthy Adults: A Pilot Randomized, Double-Blind, Placebo-Controlled, Parallel-Arm Trial

Microalgae, a marine-derived natural ingredient, has emerged as a rich source of bioactive compounds with the potential to modulate gut-brain axis activities. The objective of this study was to investigate whether supplementation with a microalgae extract from Tetradesmus obliquus strain Mi175.B1.a (TOME) influences gut health and reduces stress and anxiety in healthy adults experiencing mild to moderate gastrointestinal (GI) distress. Methods: Fifty-six healthy adults (age: 31.9 ± 7.7 years; body weight: 71.8 ± 12.6 kg; BMI: 24.6 ± 2.8 kg/m2) were enrolled in a randomized, double-blind, placebo-controlled, parallel-arm clinical trial. Participants were randomly allocated to receive capsules containing either 250 mg/day of TOME or a placebo for four weeks. Primary outcomes included the assessment of GI symptoms using the Gastrointestinal Symptom Rating Scale (GSRS) and Bristol Stool Scale (BSS). Secondary outcomes focused on subjective evaluation of mood, stress, and anxiety, as well as blood pressure responses to sympathetic nervous system activation induced by the cold pressor test (CPT). In addition, stool, plasma, and saliva samples were collected to assess biomarkers associated with stress, sympathetic activation, intestinal permeability, and GI health. 16S rRNA sequencing was performed to analyze changes in gut microbial populations. Results: Daily supplementation for four weeks with TOME was safe and well tolerated in the study population. In addition, TOME significantly reduced GSRS global scores (p = 0.02), as well as constipation (p = 0.05) and indigestion (p = 0.03) subcomponent scores compared to Placebo. There was also a significant increase in Shannon's index before FDR correction (p = 0.05; FDR = 0.12) and stool butyrate level was significantly lower in the TOME group than in Placebo after 4 weeks of supplementation (p = 0.039). Both groups showed a significant reduction in perceived stress scores, but the TOME intervention group also had reduced Negative Affect scores (p < 0.001). In addition, plasma chromogranin A, a stress biomarker, was significantly reduced after TOME intervention (p = 0.03). There were no negative effects on blood lipids or other parameters related to sympathetic activation or cardiovascular health. Conclusions: Overall, these results suggest that 4-week supplementation with T. obliquus strain Mi175.B1.a improves GI symptoms, potentially through effects on the gut microbiota, and may promote positive effects on mental health. Additional research should follow up on mental health outcomes in populations with increased stress and anxiety and investigate mechanisms underlying improvements in GI health. This trial was registered at clinicaltrials.gov as NCT06425094.

Glycaemic sugar metabolism and the gut microbiota: past, present and future

Non-communicable diseases (NCDs), such as type 2 diabetes (T2D) and metabolic dysfunction-associated fatty liver disease, have reached epidemic proportions worldwide. The global increase in dietary sugar consumption, which is largely attributed to the production and widespread use of cheap alternatives such as high-fructose corn syrup, is a major driving factor of NCDs. Therefore, a comprehensive understanding of sugar metabolism and its impact on host health is imperative to rise to the challenge of reducing NCDs. Notably, fructose appears to exert more pronounced deleterious effects than glucose, as hepatic fructose metabolism induces de novo lipogenesis and insulin resistance through distinct mechanisms. Furthermore, recent studies have demonstrated an intricate relationship between sugar metabolism and the small intestinal microbiota (SIM). In contrast to the beneficial role of colonic microbiota in complex carbohydrate metabolism, sugar metabolism by the SIM appears to be less beneficial to the host as it can generate toxic metabolites. These fermentation products can serve as a substrate for fatty acid synthesis, imposing negative health effects on the host. Nevertheless, due to the challenging accessibility of the small intestine, our knowledge of the SIM and its involvement in sugar metabolism remains limited. This review presents an overview of the current knowledge in this field along with implications for future research, ultimately offering potential therapeutic avenues for addressing NCDs.

A Data-Driven Approach to Enhance the Prediction of Bacteria-Metabolite Interactions in the Human Gut Microbiome Using Enzyme Encodings and Metabolite Structural Embeddings

Background: The human gut microbiome is critical for host health by facilitating essential metabolic processes. Our study presents a data-driven analysis across 312 bacterial species and 154 unique metabolites to enhance the understanding of underlying metabolic processes in gut bacteria. The focus of the study was to create a strategy to generate a theoretical (negative) set for binary classification models to predict the consumption and production of metabolites in the human gut microbiome. Results: Our models achieved median balanced accuracies of 0.74 for consumption predictions and 0.95 for production predictions, highlighting the effectiveness of this approach in generating reliable negative sets. Additionally, we applied a kernel principal component analysis for dimensionality reduction. The consumption model with a polynomial kernel, and the production model with a radial basis function with 32 reduced features, showed median accuracies of 0.58 and 0.67, respectively. This demonstrates that biological information can still be captured, albeit with some loss, even after reducing the number of features. Furthermore, our models were validated on six previously unseen cases, achieving five correct predictions for consumption and four for production, demonstrating alignment with known biological outcomes. Conclusions: These findings highlight the potential of integrating data-driven approaches with machine learning techniques to enhance our understanding of gut microbiome metabolism. This work provides a foundation for creating bacteria-metabolite datasets to enhance machine learning-based predictive tools, with potential applications in developing therapeutic methods targeting gut microbes.

The Hygienic Significance of Microbiota and Probiotics for Human Wellbeing

The human body can be viewed as a combination of ecological niches inhabited by trillions of bacteria, viruses, fungi, and parasites, all united by the microbiota concept. Human health largely depends on the nature of these relationships and how they are built and maintained. However, personal hygiene practices have historically been focused on the wholesale elimination of pathogens and "hygiene-challenging microorganisms" without considering the collateral damage to beneficial and commensal species. The microbiota can vary significantly in terms of the qualitative and quantitative composition both between different people and within one person during life, and the influence of various environmental factors, including age, nutrition, bad habits, genetic factors, physical activity, medication, and hygienic practices, facilitates these changes. Disturbance of the microbiota is a predisposing factor for the development of diseases and also greatly influences the course and severity of potential complications. Therefore, studying the composition of the microbiota of the different body systems and its appropriate correction is an urgent problem in the modern world. The application of personal hygiene products or probiotics must not compromise health through disruption of the healthy microbiota. Where changes in the composition or metabolic functions of the microbiome may occur, they must be carefully evaluated to ensure that essential biological functions are unaffected. As such, the purpose of this review is to consider the microbiota of each of the "ecological niches" of the human body and highlight the importance of the microbiota in maintaining a healthy body as well as the possibility of its modulation through the use of probiotics for the prevention and treatment of certain human diseases.

Bee Pollen as a Source of Biopharmaceuticals for Neurodegeneration and Cancer Research: A Scoping Review and Translational Prospects

Bee Pollen (BP) has many advantageous properties relying on its multitargeting potential, a new tendency in managing many challenging illnesses. In cancer and neurodegeneration, the multiple effects of BP could be of unequaled importance and need further investigation. Although still limited, available data interestingly spotlights some floral sources with promising activities in line with this investigation. Adopting scoping review methodology, we have identified many crucial bioactivities that are widely recognized to individual BP compounds but remain completely untapped in this valuable bee cocktail. A wide range of these compounds have been recently found to be endowed with great potential in modulating pivotal processes in neurodegeneration and cancer pathophysiology. In addition, some ubiquitous BP compounds have only been recently isolated, while the number of studied BPs remains extremely limited compared to the endless pool of plant species worldwide. We have also elucidated that clinical profits from these promising perspectives are still impeded by challenging hurdles such as limited bioavailability of the studied phytocompounds, diversity and lack of phytochemical standardization of BP, and the difficulty of selective targeting in some pathophysiological mechanisms. We finally present interesting insights to guide future research and pave the way for urgently needed and simplified clinical investigations.

Association of dietary patterns derived by reduced-rank regression with colorectal cancer risk and mortality

PURPOSE

Unhealthy dietary patterns contribute to an increased risk of colorectal cancer (CRC). Limited prior research has used reduced rank regression (RRR) to assess dietary patterns relative to CRC risk. This study aimed to identify dietary patterns derived by RRR and assess their associations with CRC risk and mortality.

METHODS

We used data from the multicentre Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) trial. Dietary intake was assessed using a Dietary History Questionnaire. In the RRR intake of fibre, folate, and the percentage of energy from carbohydrates, saturated and unsaturated fatty acids were used as response variables. Cox models and competing risk survival regression, with age as the time scale, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC risk and mortality, respectively.

RESULTS

The median follow-up time for CRC risk (n = 1044) and mortality (n = 499) was 9.4 years (Interquartile Range: 8. 0, 10.1) and 16.9 years (11.9, 18.6), respectively. Two dietary patterns were identified: the first was characterised by high carbohydrate, folate and low fatty acid intake, and the second by high fibre and unsaturated fatty acid. Compared to participants in the first tertile of the high fibre and unsaturated fatty acid pattern, those in the third tertile had a lower risk of CRC (HR = 0.88; 95% CI: 0.76, 1.03), and colon cancer (HR = 0.85; 95% CI: 0.72, 1.01). Conversely, the high carbohydrate, high folate and low fatty acid pattern had no association with CRC outcomes. None of the dietary patterns showed associations with rectal cancer or CRC mortality.

CONCLUSION

A diet enriched with high fibre and unsaturated fatty acids may reduce the risk of CRC. These results highlight the potential protective effect of adequate fibre intake in conjunction with high consumption of unsaturated fatty acids against CRC.

Impact of the Lung Microbiota on Development and Progression of Lung Cancer

The past several years have provided a more profound understanding of the role of microbial species in the lung. The respiratory tract is a delicate ecosystem of bacteria, fungi, parasites, and viruses. Detecting microbial DNA, pathogen-associated molecular patterns (PAMPs), and metabolites in sputum is poised to revolutionize the early diagnosis of lung cancer. The longitudinal monitoring of the lung microbiome holds the potential to predict treatment response and side effects, enabling more personalized and effective treatment options. However, most studies into the lung microbiota have been observational and have not adequately considered the impact of dietary intake and air pollutants. This gap makes it challenging to establish a direct causal relationship between environmental exposure, changes in the composition of the microbiota, lung carcinogenesis, and tumor progression. A holistic understanding of the lung microbiota that considers both diet and air pollutants may pave the way to improved prevention and management strategies for lung cancer.

Nonpharmacological interventions on glycated haemoglobin in youth with type 1 diabetes: a Bayesian network meta-analysis

The available evidence on the impact of specific non-pharmacological interventions on glycaemic control is currently limited. Consequently, there is a need to determine which interventions could provide the most significant benefits for the metabolic health of young individuals with type 1 diabetes mellitus. The aim of this study was to identify optimal nonpharmacological interventions on glycaemic control, measured by glycated haemoglobin (HbA1c), in children and adolescents with type 1 diabetes. Systematic searches were conducted in PubMed, Web of Science, Scopus, and SPORTDiscus from inception to July 1, 2023. Randomised clinical trials (RCT) investigating nonpharmacological interventions (e.g., physical activity, nutrition, and behavioural therapies) were included. Primary outcome was change in HbA1c levels. Secondary outcome was change in daily insulin dose requirement. Seventy-four RCT with 6,815 participants (49.43% girls) involving 20 interventions were analysed using a network meta-analysis. Most interventions showed greater efficacy than standard care. However, multicomponent exercise, which includes aerobic and strength training (n = 214, standardised mean difference [SMD] =- 0.63, 95% credible interval [95% CrI] - 1.09 to - 0.16) and nutritional supplements (n = 146, SMD =- 0.49, - 0 .92 to - 0.07) demonstrated the greatest HbA1c reductions. These interventions also led to the larger decreases in daily insulin needs (n = 119, SMD =- 0.79, 95% CrI -  1.19 to - 0.34) and (n = 57, SMD =- 0.62, 95% CrI -  1.18 to - 0.12, respectively). The current study underscores non-pharmacological options such as multicomponent exercise and nutritional supplements, showcasing their potential to significantly improve HbA1c in youth with type 1 diabetes. Although additional research to confirm their efficacy is required, these approaches could be considered as potential adjuvant therapeutic options in the management of type 1 diabetes among children and adolescents.

Carbohydrate-Mediated Pregnancy Gut Microbiota and Neonatal Low Birth Weight

The effects of gut microbiota on the association between carbohydrate intake during pregnancy and neonatal low birth weight (LBW) were investigated. A prospective cohort study was conducted with 257 singleton-born mother-child pairs in Taiwan, and maternal dietary intake was estimated using a questionnaire, with each macronutrient being classified as low, medium, or high. Maternal fecal samples were collected between 24 and 28 weeks of gestation, and gut microbiota composition and diversity were profiled using 16S rRNA amplicon gene sequencing. Carbohydrates were the major source of total energy (56.61%), followed by fat (27.92%) and protein (15.46%). The rate of infant LBW was 7.8%, which was positively correlated with maternal carbohydrate intake. In the pregnancy gut microbiota, Bacteroides ovatus and Dorea spp. were indirectly and directly negatively associated with fetal growth, respectively; Rosenburia faecis was directly positively associated with neonatal birth weight. Maternal hypertension during pregnancy altered the microbiota features and was associated with poor fetal growth. Microbiota-accessible carbohydrates can modify the composition and function of the pregnancy gut microbiota, thus providing a potential marker to modulate deviations from dietary patterns, particularly in women at risk of hypertension during pregnancy, to prevent neonatal LBW.

Dietary Fiber in Inflammatory Bowel Disease: Are We Ready to Change the Paradigm?

Accumulating evidence from pre-clinical and clinical studies demonstrate the benefit of dietary fibers for inflammatory bowel disease (IBD). However, the majority of patients avoid or limit their consumption to manage their symptoms during the active and remission phases, although limited research supports these long-term dietary habits. Although recent evidence-based dietary guidelines highlight the importance of promoting an adequate intake of dietary fiber in IBD patients, intervention trials have not yet clearly clarified the quality and quantity of dietary fiber that should be consumed to be equally tolerated by and provide benefit for patients with IBD. This narrative review describes dietary fibers and their characteristics, analyzes the real-word studies on the impact of dietary fiber consumption in IBD in different clinical settings, and concludes with potential future directions in fiber research, focusing on the real-world needs of characterizing the consumption of fiber-rich foods and promoting their adequate intake.

Nutrition at the Intersection between Gut Microbiota Eubiosis and Effective Management of Type 2 Diabetes

Nutrition is one of the most influential environmental factors in both taxonomical shifts in gut microbiota as well as in the development of type 2 diabetes mellitus (T2DM). Emerging evidence has shown that the effects of nutrition on both these parameters is not mutually exclusive and that changes in gut microbiota and related metabolites such as short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) may influence systemic inflammation and signaling pathways that contribute to pathophysiological processes associated with T2DM. With this background, our review highlights the effects of macronutrients, carbohydrates, proteins, and lipids, as well as micronutrients, vitamins, and minerals, on T2DM, specifically through their alterations in gut microbiota and the metabolites they produce. Additionally, we describe the influences of common food groups, which incorporate varying combinations of these macronutrients and micronutrients, on both microbiota and metabolic parameters in the context of diabetes mellitus. Overall, nutrition is one of the first line modifiable therapies in the management of T2DM and a better understanding of the mechanisms by which gut microbiota influence its pathophysiology provides opportunities for optimizing dietary interventions.

Diet-microbiota associations in gastrointestinal research: a systematic review

Interactions between diet and gastrointestinal microbiota influence health status and outcomes. Evaluating these relationships requires accurate quantification of dietary variables relevant to microbial metabolism, however current dietary assessment methods focus on dietary components relevant to human digestion only. The aim of this study was to synthesize research on foods and nutrients that influence human gut microbiota and thereby identify knowledge gaps to inform dietary assessment advancements toward better understanding of diet-microbiota interactions. Thirty-eight systematic reviews and 106 primary studies reported on human diet-microbiota associations. Dietary factors altering colonic microbiota included dietary patterns, macronutrients, micronutrients, bioactive compounds, and food additives. Reported diet-microbiota associations were dominated by routinely analyzed nutrients, which are absorbed from the small intestine but analyzed for correlation to stool microbiota. Dietary derived microbiota-relevant nutrients are more challenging to quantify and underrepresented in included studies. This evidence synthesis highlights advancements needed, including opportunities for expansion of food composition databases to include microbiota-relevant data, particularly for human intervention studies. These advances in dietary assessment methodology will facilitate translation of microbiota-specific nutrition therapy to practice.

The Use of Fruit and Vegetable by-Products as Enhancers of Health Status of Piglets after Weaning: The Role of Bioactive Compounds from Apple and Carrot Industrial Wastes

At weaning, piglets are exposed to a large variety of stressors, from environmental/behavioral factors to nutritional stress. Weaning transition affects the gastrointestinal tract especially, resulting in specific disturbances at the level of intestinal morphology, barrier function and integrity, mucosal immunity and gut microbiota. All these alterations are associated with intestinal inflammation, oxidative stress and perturbation of intracellular signaling pathways. The nutritional management of the weaning period aims to achieve the reinforcement of intestinal integrity and functioning to positively modulate the intestinal immunity and that of the gut microbiota and to enhance the health status of piglets. That is why the current research is focused on the raw materials rich in phytochemicals which could positively modulate animal health. The composition analysis of fruit, vegetable and their by-products showed that identified phytochemicals could act as bioactive compounds, which can be used as modulators of weaning-induced disturbances in piglets. This review describes nutritional studies which investigated the effects of bioactive compounds derived from fruit (apple) and vegetables (carrot) or their by-products on the intestinal architecture and function, inflammatory processes and oxidative stress at the intestinal level. Data on the associated signaling pathways and on the microbiota modulation by bioactive compounds from these by-products are also presented.