Overall Dietary Quality Relates to Gut Microbiota Diversity and Abundance

A gut-focused perinatal dietary intervention is associated with lower alpha diversity of the infant gut microbiota: results from a randomised controlled trial

OBJECTIVES

In experimental models, the prenatal diet influences gut microbiota composition in mothers and offspring; however, it is unclear whether this occurs in humans. We investigated the effects of a gut-focused perinatal dietary intervention on maternal and infant gut microbiota composition four weeks after birth.

METHODS

This randomised controlled trial randomised pregnant women to receive dietary advice as part of standard care, or additionally receive a dietary intervention focused on the Australian Dietary Guidelines and increasing prebiotic and probiotic/fermented food intakes (ACTRN12616000936426). Study assessments occurred from gestation week 26 (baseline) to four weeks postpartum (follow-up). Faecal samples, collected at baseline for mothers, and follow-up for mothers and infants, underwent 16SrRNA sequencing. The primary outcome was a between-group mean difference in infant faecal Shannon index. Secondary outcomes included between-group differences in other microbiota measures, including maternal change from baseline CLR-transformed Prevotella abundance.

RESULTS

Forty-four women and 45 infants completed the study. The mean Shannon index of infants in the intervention group was -0.35 (95% CI: -0.64, -0.06, SD: 0.52) units lower than control group infants, corresponding to a medium effect size (Cohen's D: -0.74, 95% CI: -1.34, -0.13). The findings were similar using other metrics of α-diversity. There were no between-group differences in β-diversity, nor any differentially abundant taxa in infants. The intervention increased abundances of the genus Prevotella in mothers compared to controls.

DISCUSSION

This gut-focused perinatal dietary intervention was associated with differences in the maternal and infant gut microbiota composition. Larger studies are required to replicate and extend these findings.

The Role and Molecular Pathways of SIRT6 in Senescence and Age-related Diseases

SIRT6 is a NAD+-dependent histone deacetylase with crucial roles in controlling DNA damage repair, telomere homeostasis, oxidative stress, autophagy, and other cellular processes, and it has long been recognized as a longevity-associated protein. This review details its anti-aging-related mechanisms. First, SIRT6 facilitates DNA repair pathways and maintains genome stability by deacetylating histone H3 at K56, K9, and K18 residues, in addition to participating in DNA damage repair through mono-ADP-ribosylation and other mechanisms. Second, SIRT6 preserves telomere integrity and mitigates cellular senescence by reducing oxidative stress-induced damage through the regulation of reactive oxygen species (ROS), inhibition of inflammation, and other pathways. Furthermore, SIRT6 promotes autophagy, slowing cellular senescence via the modulation of various signaling pathways, including AMPK, IGF-Akt-mTOR, H133Y, IL-1β, and mitochondrial autophagy-related proteins. Finally, SIRT6 regulates multiple signaling pathways, such asNF-κB, FOXO, and AMPK, to counteract the aging process. This review particularly delves into the interplay between SIRT6 and various diseases, including tumors, cardiovascular diseases (e.g., atherosclerosis, heart failure), metabolic diseases (e.g., type 2 diabetes, dyslipidemia, gluconeogenesis, osteoporosis), and neurodegenerative diseases (e.g., Alzheimer's disease). Moreover, recent advancements in SIRT6-regulated compounds (e.g., C3G, BZBS, Fisetin, FNDC5, Lycorine hydrochloride, and Ergothioneine) are discussed as potential therapeutic agents for these mediated diseases.

Gut microbiome diversity and nutrition intake in post-stroke patients

AIM

This study aimed to investigate the association between energy intake and gut microbiome diversity in patients following stroke.

METHODS

A cross-sectional study was conducted with 156 patients following stroke aged ≥65 years admitted to a rehabilitation hospital (mean age, 78 ± 7 years; 69 women). Energy intake was calculated from average food consumption during the first week after admission. Gut microbiome diversity was assessed using three indices derived from 16S rRNA sequencing of stool samples: the Shannon index, operational taxonomic unit (OTU) richness and Faith's phylogenetic diversity (PD). Sex-stratified multiple linear regression analysis evaluated the association between energy intake and gut microbiome diversity, adjusting for confounders such as age, body weight, inflammation markers, nutritional status, and medication.

RESULTS

The study included 156 patients following stroke (mean age, 78 ± 7 years; 69 women). The median energy intake was 1600 (interquartile range [IQR], 1400-1800] kcal/day for all participants. The median for gut microbiome diversity indices were Shannon index, 6.3 (IQR, 5.9-6.5); OTU richness, 217.3 (IQR, 181.9-258.1); and Faith's PD, 22.4 (IQR, 19.3-27.2). In women, energy intake was significantly positively associated with the Shannon index (β = 0.233, P = 0.026), OTU richness (β = 0.228, P = 0.036), and Faith's PD (β = 0.212, P = 0.038). In men, energy intake was significantly positively associated with the Shannon index (β = 0.230, P = 0.027), OTU richness (β = 0.211, P = 0.040), and Faith's PD (β = 0.198, P = 0.043).

CONCLUSIONS

Adequate energy intake may play an important role in preserving gut microbiome diversity in patients. Further longitudinal studies are needed to confirm these associations, clarify causality, and explore underlying mechanisms. Geriatr Gerontol Int 2025; 25: 535-542.

Association of Prepregnancy Body Mass Index with Gut Microbiota Diversity and Abundance in Pregnant Women

BACKGROUND

Understanding the link between prepregnancy nutritional status and gut microbiota during pregnancy may lead to novel maternal and child health interventions.

OBJECTIVE

To explore the association of prepregnancy body mass index (BMI) status with gut microbiota diversity and abundance during pregnancy.

METHODS

A cross-sectional study was conducted on 90 pregnant women from primary health centers in Jakarta, Indonesia. Trained staff interviewed women on sociodemographic characteristics and nutrient intake, gathered data on prepregnancy BMI from antenatal records, and obtained fecal samples. Samples were analyzed for microbiota diversity indices [Shannon, Faith phylogenetic diversity (Faith PD), and Chao1] and abundance using 16S ribosome ribonucleic acid sequencing. Multivariate logistic regression was performed adjusting for carbohydrate and protein intake, ethnicity, and education to determine the relationship between prepregnancy BMI and the alpha diversity indices and the presence of the phylum Firmicutes and genera Prevotella and Blautia.

RESULTS

Pregnant women who were overweight or obese (BMI ≥23.0 kg/m2) before pregnancy had significantly lower odds of having gut microbiota diversity above the median of the Shannon index [adjusted odds ratio (aOR): 0.37, 95% confidence interval (CI): 0.14, 0.97, P = 0.042], Faith PD (aOR: 0.23, 95% CI: 0.07, 0.75, P = 0.015), and Chao1 (aOR: 0.25, 95% CI: 0.09, 0.67, P = 0.006) compared with those who were neither overweight nor obese. Prepregnant women who were overweight or obese also had significantly lower odds of having levels above the median of the phylum Firmicutes (aOR: 0.38, 95% CI: 0.15, 0.98, P = 0.045) and genus Blautia (aOR: 0.32, 95% CI: 0.12, 0.85, P = 0.022) compared with women who were neither overweight nor obese.

CONCLUSIONS

Prepregnancy overweight or obese status was associated with lower gut microbiota diversity and lower abundance of Firmicutes and Blautia among pregnant women in an urban community. These findings suggest that prepregnancy interventions to control BMI may improve gut flora and potentially benefit pregnant women.

Macronutrient balance determines the human gut microbiome eubiosis: insights from in vitro gastrointestinal digestion and fermentation of eight pulse species

The interactions between macronutrients, the human gut microbiome, and their metabolites (short-chain fatty acids) were comprehensively investigated via an in vitro digestion and fermentation model subjected to eight pulse species. 16S rRNA sequencing and taxonomic analysis of pulse digesta fermented for up to 24 h revealed an increase in the relative abundance of gut health-detrimental genera represented by Escherichia-Shigella in kidney bean, soybean, cowpea, chickpea, and black bean samples. In contrast, the relative abundance of health-positive genera, including Bacteroides, Eubacterium, and Akkermansia, was elevated in red bean, mung bean, and Heunguseul. At the same time, the proportion of the pathogenic Escherichia-Shigella decreased. Concurrently, these three species exhibited an increase in microbial diversity as evidenced by the calculation of α-diversity (Shannon index) and β-diversity (Bray-Curtis distance). Despite the lower nutrient contents in the three pulses, represented by carbohydrates, amino acids, and fatty acids, network analysis revealed that the nutrient contents in the pulse digesta possess complex positive or negative correlations with a variety of bacteria, as well as their metabolites. These correlations were more pronounced in red bean, mung bean, and Heunguseul than in the other pulses. It was postulated that the overall potential to nourish gut environments in these species was due to the balance of their nutritional components. The linear regression analysis demonstrated that there was a negative association between carbohydrate and amino acid contents and the increase in Shannon indices. Furthermore, the ratio of carbohydrates to fatty acids and amino acids to fatty acids displayed negative correlations with the diversity increase. The ratio of carbohydrates to amino acids showed a weak positive correlation. It is noteworthy that a diet comprising foods with a balanced nutritional profile supports the growth of beneficial gut microbes, thereby promoting microbial eubiosis. Consistent work on different ingredients is essential for precise insight into the interplay between food and the human microbiome in complex dietary patterns.

Resilience to Global Health Challenges Through Nutritional Gut Microbiome Modulation

As the world faces an escalating challenge of non-communicable diseases (NCDs), with phenotypes ranging from allergic chronic immuno-inflammatory diseases to neuropsychiatric disorders, it becomes evident that their seeds are sown during the early stages of life. Furthermore, within only a few decades, human obesity has reached epidemic proportions and now represents the most serious public health challenge of our time. Recent demonstrations that a growing number of these conditions are linked to aberrant gut microbiota composition and function have evoked active scientific interest in host-microbe crosstalk, characterizing and modulating the gut microbiota in at-risk circumstances. These efforts appear particularly justified during the most critical period of developmental plasticity when the child's immune, metabolic, and microbiological constitutions lend themselves to long-term adjustment. Pregnancy and early infancy epitomize an ideal developmental juncture for preventive measures aiming to reduce the risk of NCDs; by promoting the health of pregnant and lactating women today, the health of the next generation(s) may be successfully improved. The perfect tools for this initiative derive from the earliest and most massive source of environmental exposures, namely the microbiome and nutrition, due to their fundamental interactions in the function of the host immune and metabolic maturation.

16S rRNA sequencing-based evaluation of the protective effects of key gut microbiota on inhaled allergen-induced allergic rhinitis

Introduction

Allergic rhinitis (AR) is a common respiratory disorder influenced by various factors in its pathogenesis. Recent studies have begun to emphasize the significant role of gut microbiota in immune modulation and its potential association with the development of AR. This research aims to characterize the gut microbiota of patients with AR who are sensitized via inhalation, utilizing 16S rRNA sequencing to shed light on the pathogenesis of AR and identify potential therapeutic targets.

Methods

To achieve the study's objectives, we compared the microbiota profiles between patients with AR and healthy controls. Microbial diversity was assessed using alpha and beta diversity indices, and differential microbiota populations were identified through Linear discriminant analysis Effect Size (LEfSe) analysis. A Least Absolute Shrinkage and Selection Operator (LASSO) regression model was employed to pinpoint key species. Additionally, PICRUSt2 was utilized to predict the functional pathways associated with these identified species.

Results

The analysis identified a total of 1,122 common species, along with 1,803 species associated with AR and 1,739 species associated with healthy controls. LEfSe analysis revealed 20 significant discrepancies at the genus level. The LASSO regression model identified 8 key genera, including Prevotellaceae UCG-004 and Rhodococcus, which exhibited AUC values exceeding 0.7, indicating strong diagnostic potential. Furthermore, functional pathway analysis suggested that these pivotal species are involved in pathways such as L-lysine biosynthesis and photorespiration, potentially contributing to the pathogenesis of AR.

Discussion

This study identifies critical gut microbiota that could serve as potential biomarkers for allergic rhinitis, providing new insights into its pathogenesis and offering avenues for future therapeutic strategies. Further investigation into these microbiota may lead to enhanced understanding and management of AR.

Diet-Gut Microbiota Relations: Critical Appraisal of Evidence From Studies Using Metagenomics

Diet may influence the gut microbiota and subsequently affect the host's health. Recent developments in methods analyzing the composition and function of the gut microbiota allow a deeper understanding of diet-gut microbiota relationships. A state-of-the-art methodology, shotgun metagenomics sequencing, offers a higher taxonomic resolution of the gut microbiota at the bacterial species and strain levels, and more accurate information regarding the functional potential of gut microbiota. Here, the available evidence on the relationship between diet and gut microbiota was critically reviewed, focusing on results emerging from recent metagenomics sequencing studies applied in randomized controlled trials and observational studies. The PubMed and Embase databases were used to search publications between January 2011 and September 2023. Thus far, the number of studies is limited, and the study designs and methods utilized have been variable. Nevertheless, the cumulative evidence from interventions relates to dietary fiber as a modifier of bacterial species, such as Anaerostipes hadrus and Faecalibacterium prausnitzii. Furthermore, observational studies have detected associations between different dietary patterns and food groups with certain microbial species. Utilization of metagenomics sequencing is becoming more common and will undoubtedly provide further insights into diet-gut microbiota relationships at the species level as well as their functional pathways in the near future. For reproducible results and to draw reliable conclusions across various studies on diet-gut microbiota relationships, there is a need for harmonization of the study designs and standardized ways of reporting.

Influence of feeding black soldier fly (Hermetia illucens), cricket (Gryllodes sigillatus), and superworm (Zophobas morio) on the gut microbiota of rainbow trout (Oncorhynchus mykiss)

AIM

This study investigates how replacing fishmeal and fish oil with insect meals in feed impacts the gut microbiota in rainbow trout (Oncorhynchus mykiss), a crucial species in aquaculture.

METHODS AND RESULTS

Dietary inclusion of black soldier fly (Hermetia illucens), cricket (Gryllodes sigillatus), and superworm (Zophobas morio) were evaluated for their impact on intestinal microbial diversity and community composition following a 12-week feeding trial. Fish were fed one of four isonitrogenous and isoenergetic diets: a control diet without insect meal, and diets with 15% defatted black soldier fly meal, full-fat adult cricket meal, or full-fat superworm meal. The microbiota of intestinal digesta and fish feed was characterized using 16S rRNA gene sequencing on the Illumina MiSeq platform. Results revealed significantly lower alpha diversity indices in the cricket treatment compared to the control. Beta diversity analysis showed Bacillota as the dominant phylum across all treatments, with the initial stock population richer in Mycoplasmatota. A novel genus within Mycoplasmataceae was prevalent at Day 0 and in all treatments. Black soldier fly meal increased an unidentified Peptostreptococcaceae genus (bsv123) compared to control and superworm diets, while cricket meal elevated Streptococcus levels.

CONCLUSIONS

Insect-based diets, particularly with black soldier fly meal, significantly alter beta diversity within the gut microbiota of rainbow trout, with cricket meal reducing alpha diversity and superworm having minimal impact.

Designing a behaviour change intervention using COM-B and the Behaviour Change Wheel: Co-designing the Healthy Gut Diet for preventing gestational diabetes

BACKGROUND

Evidence suggests that modulating the gut microbiota during pregnancy may help prevent gestational diabetes mellitus (GDM). The Healthy Gut Diet study is a complex behaviour change intervention co-designed with women who have a lived experience of GDM. The aim of the study was to describe the development of the behaviour change dietary intervention, the Healthy Gut Diet.

METHODS

This study followed the process for designing behaviour change interventions using the Behaviour Change Wheel. Six researchers and 12 women with lived experience participated in online workshops to co-design the Healthy Gut Diet intervention. This included "diagnosing" the barriers and enablers to two target behaviours: eating more plant foods and eating less ultra processed/saturated fat containing foods. Content analysis of the workshop transcripts and activities was undertaken, underpinned by the Capability, Opportunity, Motivation and Behaviour (COM-B) model and the Theoretical Domains Framework (TDF).

RESULTS

Barriers and enablers to the target behaviours were described across all six COM-B components and 10 TDF domains. The intervention functions for the Healthy Gut Diet were education, enablement, environmental restructuring, persuasion and incentivisation. Forty behaviour change techniques were integrated into five modes of delivery for the Healthy Gut Diet intervention. The feasibility, acceptability and effectiveness of the Healthy Gut Diet is being tested within a randomised controlled trial.

CONCLUSIONS

Using the Behaviour Change Wheel process in partnership with consumers resulted in a clearly described complex intervention targeting barriers and enablers of dietary behaviour change to improve the gut microbiota diversity in pregnant women.

Dietary Dihydromyricetin Zinc Chelate Supplementation Improves the Intestinal Health of Magang Geese

To fulfill the nutritional requirements of poultry, effective Zn supplementation is required due to Zn deficiency in basic feed. In this study, we investigated the effects of DMY-Zn (dihydromyricetin zinc chelate) on the growth performance, morphology, and biochemical indices; the expression of intestinal barrier-related genes; the intestinal microflora; and the cecum metabolome of Magang geese. A total of 300 14-day-old Magang geese (equal number of males and females) with an average body weight of 0.82 ± 0.08 kg were randomly divided into five groups and fed a basal diet; these groups were given DMY-Zn (low, medium, or high level of DMY-Zn with 30, 55, or 80 mg/kg Zn added to the basal diet) or ZnSO4 (80 mg/kg Zn added) for 4 weeks. Our results revealed that DMY-Zn significantly impacts growth and biochemical indices and plays a significant role in regulating the intestinal barrier and microflora. DMY-Zn is involved in the upregulation of intestinal barrier gene (ZO1 and MUC2) expression, as well as upregulated Zn-related gene expression (ZIP5). On the other hand, a low concentration of DMY-Zn increased the ɑ diversity index and the abundance of Lactobacillus and Faecalibacterium. Additionally, a cecal metabolomics study showed that the main metabolic pathways affected by DMY-Zn were the pentose phosphate pathway, the biosynthesis of different alkaloids, and the metabolism of sphingolipids. In conclusion, DMY-Zn can reduce feed intake, increase the expression of intestinal barrier-related genes, help maintain the intestinal microflora balance, and increase the abundance of beneficial bacteria in the intestine to improve intestinal immunity.

Host-diet-microbiota interplay in intestinal nutrition and health

The intestine is populated by a complex and dynamic assortment of microbes, collectively called gut microbiota, that interact with the host and contribute to its metabolism and physiology. Diet is considered a key regulator of intestinal microbiota, as ingested nutrients interact with and shape the resident microbiota composition. Furthermore, recent studies underscore the interplay of dietary and microbiota-derived nutrients, which directly impinge on intestinal stem cells regulating their turnover to ensure a healthy gut barrier. Although advanced sequencing methodologies have allowed the characterization of the human gut microbiome, mechanistic studies assessing diet-microbiota-host interactions depend on the use of genetically tractable models, such as Drosophila melanogaster. In this review, we first discuss the similarities between the human and fly intestines and then we focus on the effects of diet and microbiota on nutrient-sensing signaling cascades controlling intestinal stem cell self-renewal and differentiation, as well as disease. Finally, we underline the use of the Drosophila model in assessing the role of microbiota in gut-related pathologies and in understanding the mechanisms that mediate different whole-body manifestations of gut dysfunction.

Innovative treatments for obesity and NAFLD: A bibliometric study on antioxidants, herbs, phytochemicals, and natural compounds

The increasing scientific interest in antioxidants and naturally derived compounds as potential remedies for obesity and non-alcoholic fatty liver disease (NAFLD) has led to extensive research. The objective of this bibliometric analysis is to present an updated perspective on the topic of antioxidants, herbs, phytochemicals, and natural compounds, in the control of obesity and NAFLD, to identify new areas for future research. Publications from the years 2012-2022 were retrieved using the Scopus database. The research trends were analyzed using the Biblioshiny and VOSviewer tools. The field has seen a significant increase in research activity, as indicated by an annual growth rate of 10 % in the number of published manuscripts. China, Korea, and the USA emerged as the most prominent contributors in this specific field, supported by their notable volumes of publications and citations. The density analysis revealed that the most frequently occurring authors' keywords related to herbal species are, in rank order, Camelia sinensis, Momordica charantia, Curcuma longa, Ilex paraguariensis, Panax ginseng, Moringa oleifera, Garcinia cambogia, Garcinia mangostana, Zingiber officinale, and Cinnamomum verum. In the group of antioxidants, phytochemicals, and natural compounds, the top 10 were resveratrol, curcumin, quercetin, vitamin E, alpha-lipoic acid, vitamin C, chlorogenic acid, lycopene, fucoxanthin, and berberine. The co-occurrence analysis unveiled significant themes and potential trends, including a notable interest in the impact of herbal species, antioxidants, phytochemicals, and natural compounds on obesity and NAFLD through the modulation of the gut microbiome. Another recurring theme that arises, is the ongoing investigation of molecular targets that demonstrate anti-adipogenesis properties. The analysis presented in this study provides valuable insights for researchers investigating the efficacy of antioxidants, herbs, phytochemicals, and natural compounds in addressing obesity and NAFLD. Through the use of bibliometric methods, the study offers a comprehensive overview. Furthermore, the findings of this analysis can serve as a foundation for future research in this specific domain.

Tannic acid protects against colitis by regulating the IL17 - NFκB and microbiota - methylation pathways

Tannic acid, a bioactive polyphenol found in various phytogenic foods and medicinal plants, has potential prevention effects on colitis, though more evidence and mechanistic studies are required to substantiate this. In this study, we investigated the effects of different doses from 0 to 3 mg/mL of tannic acid on mice, ultimately selecting a dose of 3 mg/mL for the anti-colitis trial based on growth and intestinal morphology assessments. Using the DSS-induced colitis model, we found that tannic acid may alleviate colitis by inhibiting the IL-17 - NF-κB p65 signaling pathway and modulating epigenetic pathways, particularly methylation modifications. Additionally, tannic acid altered the gut microbiota, increasing the abundances of Prevotella, Eubacterium_siraeum_group, and Enterorhabdus in the colon. Supplementation with Eubacterium siraeum via gavage also inhibited colitis, accompanied by increased folate and methylation regulators in the colon. These findings suggest that tannic acid may inhibit colitis through the suppression of the IL-17 - NF-κB pathway and the enhancement of microbiota-mediated methylation pathways.

Relationship between dietary diversity and sleep quality: a Chinese community-based study

OBJECTIVES

The objective of this study was to examine the association between dietary diversity and sleep quality among Chinese middle-aged and older adults.

METHODS

The Lifestyle and Healthy Aging of Chinese Square Dancer Study is a prospective, community-based cohort study that enrolled participants aged 45 years and above from 2020 to 2021. Using the semiquantitative food frequency questionnaire to investigate the diets of study participants, and using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Dietary diversity was assessed using two scoring methods covering ten food groups and 66 food items, respectively: the dietary diversity score (DDS) and the food variety score (FVS). The higher scores of DDS and FVS indicated greater dietary diversity and higher dietary quality. Logistic regression analysis explored the associations between these scores and sleep quality.

RESULTS

A total of 2409 individuals with completed information on PSQI and FFQ were included in this study, of whom 767 (31.8%) had poor sleep quality. Participants with higher DDS were associated with an 18% lower odds of poor sleep quality compared to those with low DDS (OR = 0.82, 95% CI, 0.68-0.98). Participants in the highest quartile of the FVS had a 32% lower odds of poor sleep quality than those in the lowest quartile (OR = 0.68, 95% CI, 0.52-0.89).

CONCLUSIONS

There was a positive correlation between higher FVS and DDS with better sleep quality. Therefore, ensuring a diverse diet may be beneficial for maintaining good sleep quality among middle-aged and older adults.

Maternal dietary intervention during lactation impacts the maternal faecal and human milk microbiota

AIMS

To determine the effect of a two-week reduced fat and sugar and increased fibre maternal dietary intervention on the maternal faecal and human milk (HM) microbiomes.

METHODS AND RESULTS

Faecal swabs and HM samples were collected from mothers (n = 11) immediately pre-intervention, immediately post-intervention, and 4 and 8 weeks post-intervention, and were analysed using full-length 16S rRNA gene sequencing. Maternal macronutrient intake was assessed at baseline and during the intervention. Maternal fat and sugar intake during the intervention were significantly lower than pre-intervention (P = <0.001, 0.005, respectively). Significant changes in the bacterial composition of maternal faeces were detected after the dietary intervention, with decreases in the relative abundance of Bacteroides caccae (P = <0.001) and increases in the relative abundance of Faecalibacillus intestinalis (P = 0.006). In HM, the diet resulted in a significant increase in Cutibacterium acnes (P = 0.001) and a decrease in Haemophilus parainfluenzae (P = <0.001). The effect of the diet continued after the intervention, with faecal swabs and HM samples taken 4 and 8 weeks after the diet showing significant differences compared to baseline.

CONCLUSION

This pilot study demonstrates that short-term changes in maternal diet during lactation can alter the bacterial composition of the maternal faeces and HM.

The Development and Evaluation of a Literature-Based Dietary Index for Gut Microbiota

The aim of the study was to develop and evaluate a novel dietary index for gut microbiota (DI-GM) that captures dietary composition related to gut microbiota profiles. We conducted a literature review of longitudinal studies on the association of diet with gut microbiota in adult populations and extracted those dietary components with evidence of beneficial or unfavorable effects. Dietary recall data from the National Health and Nutrition Examination Survey (NHANES, 2005-2010, n = 3812) were used to compute the DI-GM, and associations with biomarkers of gut microbiota diversity (urinary enterodiol and enterolactone) were examined using linear regression. From a review of 106 articles, 14 foods or nutrients were identified as components of the DI-GM, including fermented dairy, chickpeas, soybean, whole grains, fiber, cranberries, avocados, broccoli, coffee, and green tea as beneficial components, and red meat, processed meat, refined grains, and high-fat diet (≥40% of energy from fat) as unfavorable components. Each component was scored 0 or 1 based on sex-specific median intakes, and scores were summed to develop the overall DI-GM score. In the NHANES, DI-GM scores ranged from 0-13 with a mean of 4.8 (SE = 0.04). Positive associations between DI-GM and urinary enterodiol and enterolactone were observed. The association of the novel DI-GM with markers of gut microbiota diversity demonstrates the potential utility of this index for gut health-related studies.

Human milk microbiome: associations with maternal diet and infant growth

Introduction

Ingestion of human milk (HM) is identified as a significant factor associated with early infant gut microbial colonization, which has been associated with infant health and development. Maternal diet has been associated with the HM microbiome (HMM). However, a few studies have explored the associations among maternal diet, HMM, and infant growth during the first 6 months of lactation.

Methods

For this cross-sectional study, Mam-Mayan mother-infant dyads (n = 64) were recruited from 8 rural communities in the Western Highlands of Guatemala at two stages of lactation: early (6-46 days postpartum, n = 29) or late (109-184 days postpartum, n = 35). Recruited mothers had vaginally delivered singleton births, had no subclinical mastitis or antibiotic treatments, and breastfed their infants. Data collected at both stages of lactation included two 24-h recalls, milk samples, and infant growth status indicators: head-circumference-for-age-z-score (HCAZ), length-for-age-z-score (LAZ), and weight-for-age-z-score (WAZ). Infants were divided into subgroups: normal weight (WAZ ≥ -1SD) and mildly underweight (WAZ < -1SD), non-stunted (LAZ ≥ -1.5SD) and mildly stunted (LAZ < -1.5SD), and normal head-circumference (HCAZ ≥ -1SD) and smaller head-circumference (HCAZ < -1SD). HMM was identified using 16S rRNA gene sequencing; amplicon analysis was performed with the high-resolution ANCHOR pipeline, and DESeq2 identified the differentially abundant (DA) HMM at the species-level between infant growth groups (FDR < 0.05) in both early and late lactation.

Results

Using both cluster and univariate analyses, we identified (a) positive correlations between infant growth clusters and maternal dietary clusters, (b) both positive and negative associations among maternal macronutrient and micronutrient intakes with the HMM at the species level and (c) distinct correlations between HMM DA taxa with maternal nutrient intakes and infant z-scores that differed between breast-fed infants experiencing growth faltering and normal growth in early and late lactation.

Conclusion

Collectively, these findings provide important evidence of the potential influence of maternal diet on the early-life growth of breastfed infants via modulation of the HMM.

Maternal-Foetal/Infant Interactions-Gut Microbiota and Immune Health

In recent years, the number of scientific publications on the role of intestinal microbiota in shaping human health, as well as the occurrence of intestinal dysbiosis in various disease entities, has increased dynamically. However, there is a gap in comprehensively understanding the factors influencing a child's gut microbiota. This review discusses the establishment of gut microbiota and the immunological mechanisms regulating children's microbiota, emphasising the importance of prioritising the development of appropriate gut microbiota in a child from the planning stages of pregnancy. The databases PubMed, Web of Sciences, Cochrane, Scopus and Google Scholar were searched to identify relevant articles. A child's gut microbiota composition is influenced by numerous factors, such as diet during pregnancy, antibiotic therapy, the mother's vaginal microbiota, delivery method, and, later, feeding method and environmental factors. During pregnancy, the foetus naturally acquires bacterial strains from the mother through the placenta, thereby shaping the newborn's immune system. Inappropriate maternal vaginal microbiota may increase the risk of preterm birth. Formula-fed infants typically exhibit a more diverse microbiota than their breastfed counterparts. These factors, among others, shape the maturation of the child's immune system, impacting the production of IgA antibodies that are central to cellular humoral immune defence. Further research should focus on identifying specific microbiota-immune system interactions influencing a child's immune health and developing personalised treatment strategies for immune-related disorders.

High diversity, close genetic relatedness, and favorable living conditions benefit species co-occurrence of gut microbiota in Brandt's vole

Introduction

Revealing factors and mechanisms in determining species co-existence are crucial to community ecology, but studies using gut microbiota data are still lacking.

Methods

Using gut microbiota data of 556 Brandt's voles from 37 treatments in eight experiments, we examined the relationship of species co-occurrence of gut microbiota in Brandt's voles (Lasiopodomys brandtii) with genetic distance (or genetic relatedness), community diversity, and several environmental variables.

Results

We found that the species co-occurrence index (a larger index indicates a higher co-occurrence probability) of gut microbiota in Brandt's voles was negatively associated with the genetic distance between paired ASVs and the number of cohabitating voles in the experimental space (a larger number represents more crowding social stress), but positively with Shannon diversity index, grass diets (representing natural foods), and non-physical contact within an experimental space (representing less stress).

Discussion

Our study demonstrated that high diversity, close genetic relatedness, and favorable living conditions would benefit species co-occurrence of gut microbiota in hosts. Our results provide novel insights into factors and mechanisms that shape the community structure and function of gut microbiota and highlight the significance of preserving the biodiversity of gut microbiota.

Suboptimal dietary quality is associated with mental symptoms among adults aged 40 years and over in China: A population-based cross-sectional study

BACKGROUND

The previous studies an association between dietary patterns and psychiatric symptoms. However, few studies have examined the association of quality of dietary patterns and anxiety, depressive symptoms in the Chinese population.

METHODS

Between 2017 and 2019, a population-based, cross-sectional survey was carried out in China. Uniformed questionnaires collected the demographic characteristics and food data. The dietary quality of the adults was evaluated using the revised Diet Balance Index 2016 (DBI-16). We measured anxiety and depression symptoms using the the Generalized Anxiety Disorder (GAD)-7 and Patient Health Questionnaire (PHQ)-9.

RESULTS

A total of 73,737 participants were recruited during the survey period. 17.6 % and 13.7 % of residents suffer from anxiety and depression symptoms, respectively. The DBI-16 indicates that participants with anxiety or depression symptoms had higher scores of low bound score (LBS, refers to inadequate food intake) and dietary quality distance (DQD, refers to unbalanced food intake) than those without anxiety or depression. The logistic regression models showed that high levels of LBS and DQD problems were more strongly associated with anxiety (LBS:OR = 1.20, DQD:OR = 1.30) and depressive symptoms (LBS:OR = 1.21, DQD:OR = 1.44). On the contrary, higher bound score (HBS, refers to excessive food intake) was significantly negatively correlated with symptoms of anxiety and depression. Moreover, each increase in the food group was associated with 4 % lower odds of anxiety and 6 % lower odds of depression symptoms.

LIMITATIONS

Cross-sectional design and self-reporting of psychological symptoms and dietary information limit the generalizability of the results.

CONCLUSION

The dietary quality of adults aged 40 years and over in China is suboptimal, with excessive and inadequate food intake simultaneously. Dietary imbalance, and low dietary diversity may be related to anxiety and depressive symptoms.

Impacts of nutrition counseling on depression and obesity: A scoping review

This scoping review aims to evaluate the impact of nutrition counseling on mental health and wellbeing among people affected by obesity. Depression and obesity are major sources of morbidity and mortality worldwide. The prevalence of obesity is higher in patients with severe or suboptimally managed depression. Change in dietary quality prompted by nutrition counseling may pose a unique opportunity for intervention. Of the 1745 studies identified, 26 studies (total n = 6727) met inclusion criteria. Due to the heterogeneity of methods and outcome reporting, it was not possible to perform meta-analysis. Across all included studies, 34 different scales were used to quantify mental health/wellbeing. Eleven studies (42.3%) reported statistically significant findings between intervention and control groups. Only two of these studies assessed nutrition counseling independently rather than as part of a multidisciplinary intervention. Overall, many studies have examined the role of nutrition counseling on mental health/wellbeing in individuals affected by obesity. However, due to inconsistency in study methodologies and outcome measurement tools, it is challenging to draw robust or clinically meaningful conclusions about the effects of nutrition counseling on mental health in this population.

Diet Quality and the Fecal Microbiota in Adults in the American Gut Project

BACKGROUND

The Dietary Guidelines for Americans advises on dietary intake to meet nutritional needs, promote health, and prevent diseases. Diet affects the intestinal microbiota and is increasingly linked to health. It is vital to investigate the relationships between diet quality and the microbiota to better understand the impact of nutrition on human health.

OBJECTIVES

This study aimed to investigate the differences in fecal microbiota composition in adults from the American Gut Project based on their adherence to the Dietary Guidelines for Americans.

METHODS

This study was a cross-sectional analysis of the 16S sequencing and food frequency data of a subset of adults (n = 432; age = 18-60 y; 65% female, 89% white) participating in the crowdsourced American Gut Project. The Healthy Eating Index-2015 assessed the compliance with Dietary Guideline recommendations. The cohort was divided into tertiles based on Healthy Eating Index-2015 scores, and differences in taxonomic abundances and diversity were compared between high and low scorers.

RESULTS

The mean Total Score for low-scoring adults (58.1 ± 5.4) was comparable with the reported score of the average American adult (56.7). High scorers for the Total Score and components related to vegetables, grains, and dairy had greater alpha diversity than low scorers. High scorers in the fatty acid component had a lower alpha diversity than low scorers (95% CI: 0.35, 1.85). A positive log-fold difference in abundance of plant carbohydrate-metabolizing taxa in the families Lachnospiraceae and Ruminococcaceae was observed in high-scoring tertiles for Total Score, vegetable, fruit, and grain components (Benjamini-Hochberg; q < 0.05).

CONCLUSIONS

Adults with greater compliance to the Dietary Guidelines demonstrated higher diversity in their fecal microbiota and greater abundance of bacteria capable of metabolizing complex carbohydrates, providing evidence on how Dietary Guidelines support the gut microbiota.

Diarrhea Caused by High-Fat and High-Protein Diet Was Associated With Intestinal Lactase-Producing Bacteria

BACKGROUND/AIMS

This study aimed to investigate the effect of diarrhea induced by a high-fat and high-protein diet on lactase-producing bacteria in the intestinal contents of mice from the perspective of diarrhea-related genes.

MATERIALS AND METHODS

Ten specific pathogen-free Kunming male mice were chosen and randomly divided into the normal group and model group. The mice in the normal group were fed with high-fat and high-protein diet plus gavage of vegetable oil, while those in the model group were fed with general diet plus gavage of distilled water. After successful modeling, the distribution and diversity of lactase-producing bacteria in the intestinal contents were characterized by metagenomic sequencing technology.

RESULTS

After high-fat and high-protein diet intervention, Chao1, observed species index, and operational taxonomic units number decreased in the model group (P > .05), while the Shannon, Simpson, Pielou's evenness, and Goods coverage indices increased (P > .05). The principal coordinate analysis showed that the composition of lactase-producing bacteria differed between the normal group and model group (P < .05). The lactase-producing bacterial source in the intestinal contents of mice was Actinobacteria, Firmicutes, and Proteobacteria, of which Actinobacteria was the most abundant phylum. At the genus level, both groups had their unique genera, respectively. Compared to the normal group, the abundance of Bifidobacterium, Rhizobium, and Sphingobium increased, while Lachnoclostridium, Lactobacillus, Saccharopolyspora, and Sinorhizobium decreased in the model group.

CONCLUSION

High-fat and high-protein diet altered the structure of lactase-producing bacteria in the intestinal contents, elevating the abundance of dominant lactase-producing bacteria, while decreasing the richness of lactase-producing bacteria, which may further induce the occurrence of diarrhea.

Comparative analysis of gut fungal composition and structure of the yaks under different feeding models

The yaks that inhabit the Tibetan plateau are a rare breed that is closely related to local economic development and human civilization. This ancient breed may have evolved a unique gut microbiota due to the hypoxic high-altitude environment. The gut microbiota is susceptible to external factors, but research regarding the effects of different feeding models on the gut fungal community in yaks remains scarce. In this study, we compared and analyzed the composition and variability of the gut fungal community among wild yaks (WYG), house-feeding domestic yaks (HFG), and grazing domestic yaks (GYG). The results revealed that Basidiomycota and Ascomycota were the most preponderant phyla in the gut fungal community, regardless of feeding models. Although the types of dominant fungal phyla did not change, their abundances did. Intergroup analysis of fungal diversity showed that the Shannon and Simpson indices of WYG and GYG were significantly higher than those of HFG. Fungal taxonomic analysis showed that there were 20 genera (Sclerostagonospora and Didymella) that were significantly different between WYG and GYG, and 16 genera (Thelebolus and Cystobasidium) that were significantly different between the WYG and HFG. Furthermore, the proportions of 14 genera (Claussenomyces and Papiliotrema) significantly decreased, whereas the proportions of eight genera (Stropharia and Lichtheimia) significantly increased in HFG as compared to GYG. Taken together, this study indicated that the gut fungal composition and structure differ significantly between yaks raised in different breeding groups.

Influence of grape consumption on the human microbiome

Over the years, a substantial body of information has accumulated suggesting dietary consumption of grapes may have a positive influence on human health. Here, we investigate the potential of grapes to modulate the human microbiome. Microbiome composition as well as urinary and plasma metabolites were sequentially assessed in 29 healthy free-living male (age 24-55 years) and female subjects (age 29-53 years) following two-weeks of a restricted diet (Day 15), two-weeks of a restricted diet with grape consumption (equivalent to three servings per day) (Day 30), and four-weeks of restricted diet without grape consumption (Day 60). Based on alpha-diversity indices, grape consumption did not alter the overall composition of the microbial community, other than with the female subset based on the Chao index. Similarly, based on beta-diversity analyses, the diversity of species was not significantly altered at the three time points of the study. However, following 2 weeks of grape consumption, taxonomic abundance was altered (e.g., decreased Holdemania spp. and increased Streptococcus thermophiles), as were various enzyme levels and KEGG pathways. Further, taxonomic, enzyme and pathway shifts were observed 30 days following the termination of grape consumption, some of which returned to baseline and some of which suggest a delayed effect of grape consumption. Metabolomic analyses supported the functional significance of these alterations wherein, for example, 2'-deoxyribonic acid, glutaconic acid, and 3-hydroxyphenylacetic acid were elevated following grape consumption and returned to baseline following the washout period. Inter-individual variation was observed and exemplified by analysis of a subgroup of the study population showing unique patterns of taxonomic distribution over the study period. The biological ramifications of these dynamics remain to be defined. However, while it seems clear that grape consumption does not perturb the eubiotic state of the microbiome with normal, healthy human subjects, it is likely that shifts in the intricate interactive networks that result from grape consumption have physiological significance of relevance to grape action.

HIV Tat Expression and Cocaine Exposure Lead to Sex- and Age-Specific Changes of the Microbiota Composition in the Gut

The balance of microbial communities in the gut is extremely important for normal physiological function. Disruption of the balance is often associated with various disorders and diseases. Both HIV infection and cocaine use are known to change the gut microbiota and the epithelial barrier integrity, which contribute to inflammation and immune activation. Our recent study shows that Tat expression and cocaine exposure result in changes of genome-wide DNA methylation and gene expression and lead to worsen the learning and memory impairments. In the current study, we extended the study to determine effects of Tat and cocaine on the gut microbiota composition. We found that both Tat expression and cocaine exposure increased Alteromonadaceae in 6-month-old female/male mice. In addition, we found that Tat, cocaine, or both increased Alteromonadaceae, Bacteroidaceae, Cyanobiaceae, Erysipelotrichaceae, and Muribaculaceae but decreased Clostridiales_vadinBB60_group, Desulfovibrionaceae, Helicobacteraceae, Lachnospiraceae, and Ruminococcaceae in 12-month-old female mice. Lastly, we analyzed changes of metabolic pathways and found that Tat decreased energy metabolism and nucleotide metabolism, and increased lipid metabolism and metabolism of other amino acids while cocaine increased lipid metabolism in 12-month-old female mice. These results demonstrated that Tat expression and cocaine exposure resulted in significant changes of the gut microbiota in an age- and sex-dependent manner and provide additional evidence to support the bidirectional gut-brain axis hypothesis.

Gut microbiota-mediated metabolism of green tea catechins and the biological consequences: An updated review

Multiple beneficial effects have been attributed to green tea catechins (GTCs). However, the bioavailability of GTCs is generally low, with only a small portion directly absorbed in the small intestine. The majority of ingested GTCs reaches the large intestinal lumen, and are extensively degraded via biotransformation by gut microbiota, forming many low-molecular-weight metabolites such as phenyl-γ-valerolactones, phenolic acids, butyrate, and acetate. This process not only improves the overall bioavailability of GTC-derived metabolites but also enriches the biological activities of GTCs. Therefore, the intra- and inter-individual differences in human gut microbiota as well as the resulting biological contribution of microbial metabolites are crucial for the ultimate health benefits. In this review, the microbial degradation of major GTCs was characterized and an overview of the in vitro models used for GTC metabolism was summarized. The intra- and inter-individual differences of human gut microbiota composition and the resulting divergence in the metabolic patterns of GTCs were highlighted. Moreover, the potential beneficial effects of GTCs and their gut microbial metabolites were also discussed. Overall, the microbial metabolites of GTCs with higher bioavailability and bioactive potency are key factors for the observed beneficial effects of GTCs and green tea consumption.

Possible role of nutrition in the prevention of inflammatory bowel disease-related colorectal cancer: A focus on human studies

Patients with inflammatory bowel disease (IBD) are at substantially high risk for colorectal cancer (CRC). IBD-associated CRC accounts for roughly 10% to 15% of the annual mortality in patients with IBD. IBD-related CRC also affects younger patients compared with sporadic CRC, with a 5-y survival rate of 50%. Regardless of medical therapies, the persistent inflammatory state characterizing IBD raises the risk for precancerous changes and CRC, with additional input from several elements, including genetic and environmental risk factors, IBD-associated comorbidities, intestinal barrier dysfunction, and gut microbiota modifications. It is well known that nutritional habits and dietary bioactive compounds can influence IBD-associated inflammation, microbiome abundance and composition, oxidative stress balance, and gut permeability. Additionally, in recent years, results from broad epidemiologic and experimental studies have associated certain foods or nutritional patterns with the risk for colorectal neoplasia. The present study aimed to review the possible role of nutrition in preventing IBD-related CRC, focusing specifically on human studies. It emerges that nutritional interventions based on healthy, nutrient-dense dietary patterns characterized by a high intake of fiber, vegetables, fruit, ω-3 polyunsaturated fatty acids, and a low amount of animal proteins, processed foods, and alcohol, combined with probiotic supplementation have the potential of reducing IBD-activity and preventing the risk of IBD-related CRC through different mechanisms, suggesting that targeted nutritional interventions may represent a novel promising approach for the prevention and management of IBD-associated CRC.

Relationship between Diet Quality and Maternal Stool Microbiota in the MUMS Australian Pregnancy Cohort

Dietary intake during pregnancy may influence the antenatal microbiome, which is proposed to impact maternal and infant health during the pregnancy and beyond. The aim of this sub-study was to examine associations between dietary intake and microbiota diversity during pregnancy using whole metagenomic sequencing and examine associations in low-risk versus high-risk pregnancies, as well as complicated versus uncomplicated pregnancies. Pregnancy data were analysed from women participating in the MUMS cohort study in Sydney, Australia (women followed from trimester 1 of pregnancy to 1-year postpartum), who had dietary intake data at either trimester 1 or 3, assessed using the Australian Eating Survey, and a matched stool sample (n = 86). Correlations of microbial alpha diversity with dietary intake data were determined using the repeated-measures correlation, rmcorr, in R. In the combined cohort, no associations were found between diet quality or diet composition and microbial alpha diversity or beta diversity. However, trends in our analysis suggested that dietary intake of specific macro- and micronutrients may influence microbial diversity differently, depending on particular pregnancy conditions. Our findings suggest that dietary intake during pregnancy may have a variable influence on the maternal microbiota, unique to the individual maternal pregnancy phenotype. More research is needed to disentangle these associations.

Effect of gut microbial composition and diversity on major inhaled allergen sensitization and onset of allergic rhinitis

BACKGROUND

Decreased gut microbiota diversity is associated with gut dysbiosis and causes various diseases, including allergic diseases. We investigated the relationship between gut microbial diversity and sensitization to major inhaled allergens. Furthermore, the relationship of allergic symptom onset with bacterial composition in sensitized individuals was investigated.

METHODS

This study included 1092 local residents who had participated in the Iwaki Health Promotion Project in 2016. Blood samples were analyzed to ascertain specific IgE levels against major inhaled allergens (JCP, HD1, Grass-mix, Weed-mix). Nasal symptoms were estimated by questionnaires. Fecal samples were analyzed for bacterial 16S rRNA using next generation sequencing. The diversity index (α-diversity, β-diversity) and the composition of gut microbes in phylum/order levels were compared between patients sensitized or unsensitized to allergen, and symptomatic and asymptomatic groups.

RESULTS

Some α-diversity metrics were significantly decreased in patients who were sensitized to any/all four allergens compared with the unsensitized group. β-diversity differed significantly between those unsensitized and sensitized to all allergens (aged 20-49 years), and between those unsensitized and sensitized to any/all four allergens (aged ≥50 years). The relative abundance of Bacteroidales was significantly lower in the unsensitized than in the sensitized group. The composition and diversity of gut microbiota were similar between the symptomatic and asymptomatic groups.

CONCLUSIONS

Our results suggest that lack of diversity in gut microbiota has an effect on sensitization to allergens. Bacteroidales in order level may affect sensitization; however, the onset of allergy symptoms was not significantly associated with bacterial composition and diversity.

Whole grain benefit: synergistic effect of oat phenolic compounds and β-glucan on hyperlipidemia via gut microbiota in high-fat-diet mice

Increasing evidence has confirmed that whole grain oats are effective in regulating hyperlipidemia. However, which specific ingredient is crucial remains unclear. This study focused on which whole grain components, oat phenolic compounds (OPC) or oat β-glucan (OBG), can regulate lipid metabolism and gut microbiota. The experiment unveiled that OPC and/or OBG not only reduced the body weight and fasting blood glucose (FBG) but also regulated serum and hepatic lipid levels in high-fat-diet (HFD) fed mice. There was no significant difference in the regulatory effects of OPC and OBG (p > 0.05). The combination of OPC and OBG (OPC + OBG) significantly decreased the body weight (p < 0.01) and reduced the blood glucose (p < 0.01) and lipid profile levels (p < 0.01). The real-time quantitative PCR (RT-qPCR) study revealed that OPC + OBG significantly altered mRNA expression related to lipid metabolism. Histopathological analysis showed that OPC + OBG improved liver lipid deposition as well as liver oxidative stress (p < 0.05). In addition, OPC + OBG combination regulated the gut microbiota community phenotype and increased probiotics. OPC + OBG significantly increased the abundance of Bacteroidetes and reduced the abundance of Firmicutes (p < 0.05) compared with the OPC and OBG fed mice. In conclusion, OPC + OBG has a synergistic effect in alleviating hyperlipidemia via lipid metabolism and gut microbiota composition. This finding also provided a potential justification for the advantages of whole grains in preventing hyperlipidemia.

Relationships between dietary diversity and gut microbial diversity in the elderly

Diet is considered as a major driver of gut microbiota composition. However, little is known about the relationship between overall dietary balance and gut microbiota, especially in the elderly. Here, using the Quantitative Index for Dietary Diversity (QUANTIDD), we analysed the relationships between dietary diversity and gut microbiota diversity in 445 Japanese subjects aged 65-90 years. We also examined the effect of age by comparing the young-old group aged 65 to 74 years (<75 years group; n=246) and the old-old group aged 75 years and older (≥75 years group; n=199). QUANTIDD showed significant positive relationships with Pielou's evenness and Shannon indices, two α-diversity indices related to the uniformity of species distribution. This suggests that a more diverse diet is associated with a more uniform abundance of various bacterial groups, rather than a greater variety of gut bacteria. QUANTIDD also showed significant positive associations with the abundance of Anaerostipes, Eubacterium eligens group, and Eubacterium ventriosum group, which produce short-chain fatty acids (SCFAs) and are beneficial to health. Negative association was found with the abundance of Ruminococcus gnavus group, which produces inflammatory polysaccharides. Positive associations between QUANTIDD and α-diversity indices or the abundance of specific bacterial groups were identified among all subjects and in the <75 years group, but not in the ≥75 years group. Our results suggest that dietary diversity contributes to the diversity of the gut microbiota and increases the abundance of SCFAs-producing bacteria, but only up to a certain age. These findings help to understand the complex relationship between diet and gut microbiota, and provide hints for specific dietary interventions to promote beneficial gut microbiota in the elderly.

The Role of the Microbiome in the Metabolic Health of People with Schizophrenia and Related Psychoses: Cross-Sectional and Pre-Post Lifestyle Intervention Analyses

The microbiome has been implicated in the development of metabolic conditions which occur at high rates in people with schizophrenia and related psychoses. This exploratory proof-of-concept study aimed to: (i) characterize the gut microbiota in antipsychotic naïve or quasi-naïve people with first-episode psychosis, and people with established schizophrenia receiving clozapine therapy; (ii) test for microbiome changes following a lifestyle intervention which included diet and exercise education and physical activity. Participants were recruited from the Eastern Suburbs Mental Health Service, Sydney, Australia. Anthropometric, lifestyle and gut microbiota data were collected at baseline and following a 12-week lifestyle intervention. Stool samples underwent 16S rRNA sequencing to analyse microbiota diversity and composition. Seventeen people with established schizophrenia and five people with first-episode psychosis were recruited and matched with 22 age-sex, BMI and ethnicity matched controls from a concurrent study for baseline comparisons. There was no difference in α-diversity between groups at baseline, but microbial composition differed by 21 taxa between the established schizophrenia group and controls. In people with established illness pre-post comparison of α-diversity showed significant increases after the 12-week lifestyle intervention. This pilot study adds to the current literature that detail compositional differences in the gut microbiota of people with schizophrenia compared to those without mental illness and suggests that lifestyle interventions may increase gut microbial diversity in patients with established illness. These results show that microbiome studies are feasible in patients with established schizophrenia and larger studies are warranted to validate microbial signatures and understand the relevance of lifestyle change in the development of metabolic conditions in this population.

The Gut Microbiome among Postmenopausal Latvian Women in Relation to Dietary Habits

In recent years, many studies have been initiated to characterise the human gut microbiome in relation to different factors like age, lifestyle, and dietary habits. This study aimed to evaluate the impact of yoghurt intake on the gut microbiome among postmenopausal women and how overall dietary habits modulate the gut microbiome. In total, 52 participants were included in the study and two groups—a control (n = 26) and experimental group (n = 26)—were established. The study was eight weeks long. Both study groups were allowed to consume a self-selected diet, but the experimental group had to additionally consume 175 g of plain organic milk yoghurt on a daily basis for eight weeks. In addition, a series of questionnaires were completed, including a questionnaire on the subject’s sociodemographic background, health status, and lifestyle factors, as well as a food frequency questionnaire. Stool samples were collected for the analysis of the gut microbiome (both prior to and after the eight weeks of the study). Sequencing of V4-V5 regions of the 16S rRNA gene was used to determine the bacterial composition of stool samples. The dominant phylum from the gut microbiome was Firmicutes (~70% to 73%), followed by Bacteroidota (~20% to 23%). Although no significant changes in the gut microbiome were related to daily consumption of yoghurt, we report that consumption of food products like grains, grain-based products, milk and milk products, and beverages (tea, coffee) is associated with differences in the composition of the gut microbiome. Establishing nutritional strategies to shape the gut microbiome could contribute to improved health status in postmenopausal women, but further research is needed.

Dietary variety relates to gut microbiota diversity and abundance in humans

PURPOSE

We aim to investigate the relationship between gut microbiota and dietary variety in a Chinese population using Dietary Variety Score (DVS), an index of dietary variety, as little has studied the relationship of dietary variety and gut microbiota in a general population.

METHODS

In this cross-sectional study, recruited participants were conducted with face-to-face interview to collect information on 24-h food intake and dietary consumption using a valid food frequency questionnaire. Subjects (n = 128) were divided as high and low DVS groups by the median of DVS after rigorously matching for confounding factors. The gut microbiota was assessed by 16S rRNA sequencing and the correlations between key phylotypes and DVS, Index of Nutritional Quality (INQ) and clinical indices were examined using generalized linear model in negative binomial regression.

RESULTS

Higher score of DVS, INQVB6, INQVE and INQZn exhibited higher α-diversity. DVS was correlated with INQ and six genera. Among the DVS-correlated genera, Turicibacter, Alistipes and Barnesiella were positively correlated with INQVE, INQZn and INQCu, individually or in combination, while Cetobacterium was negatively correlated with INQCu, INQZn and INQVE. The abundance of Coprococcus and Barnesiella increased with the elevated cumulative scores of INQVE, INQVB6 and INQZn. The combination of Alistipes, Roseburia and Barnesiella could moderately predict dietary variety status.

CONCLUSION

Higher DVS was correlated with higher microbial diversity and more abundance of some potentially beneficial bacteria but with less some potentially pathogenic bacteria. A high variety dietary, therefore, should be recommended in our daily life.

Distinct Diet-Microbiota-Metabolism Interactions in Overweight and Obese Pregnant Women: a Metagenomics Approach

Diet and gut microbiota are known to modulate metabolic health. Our aim was to apply a metagenomics approach to investigate whether the diet-gut microbiota-metabolism and inflammation relationships differ in pregnant overweight and obese women. This cross-sectional study was conducted in overweight (n = 234) and obese (n = 152) women during early pregnancy. Dietary quality was measured by a validated index of diet quality (IDQ). Gut microbiota taxonomic composition and species diversity were assessed by metagenomic profiling (Illumina HiSeq platform). Markers for glucose metabolism (glucose, insulin) and low-grade inflammation (high sensitivity C-reactive protein [hsCRP], glycoprotein acetylation [GlycA]) were analyzed from blood samples. Higher IDQ scores were positively associated with a higher gut microbiota species diversity (r = 0.273, P = 0.007) in obese women, but not in overweight women. Community composition (beta diversity) was associated with the GlycA level in the overweight women (P = 0.04) but not in the obese. Further analysis at the species level revealed a positive association between the abundance of species Alistipes finegoldii and the GlycA level in overweight women (logfold change = 4.74, P = 0.04). This study has been registered at ClinicalTrials.gov under registration no. NCT01922791 (https://clinicaltrials.gov/ct2/show/NCT01922791).

IMPORTANCE We observed partially distinct diet-gut microbiota-metabolism and inflammation responses in overweight and obese pregnant women. In overweight women, gut microbiota community composition and the relative abundance of A. finegoldii were associated with an inflammatory status. In obese women, a higher dietary quality was related to a higher gut microbiota diversity and a healthy inflammatory status.

Additional Resistant Starch from One Potato Side Dish per Day Alters the Gut Microbiota but Not Fecal Short-Chain Fatty Acid Concentrations

The composition of the gut microbiota and their metabolites are associated with cardiometabolic health and disease risk. Intake of dietary fibers, including resistant starch (RS), has been shown to favorably affect the health of the gut microbiome. The aim of this research was to measure changes in the gut microbiota and fecal short-chain fatty acids as part of a randomized, crossover supplemental feeding study. Fifty participants (68% female, aged 40 ± 13 years, BMI 24.5 ± 3.6 kg/m²) completed this study. Potato dishes (POT) contained more RS than refined grain dishes (REF) (POT: 1.31% wet basis (95% CI: 0.94, 1.71); REF: 0.73% wet basis (95% CI: 0.34, 1.14); p = 0.03). Overall, potato dish consumption decreased alpha diversity, but beta diversity was not impacted. Potato dish consumption was found to increase the abundance of Hungatella xylanolytica, as well as that of the butyrate producing Roseburia faecis, though fecal butyrate levels were unchanged. Intake of one potato-based side dish per day resulted in modest changes in gut microbiota composition and diversity, compared to isocaloric intake of refined grains in healthy adults. Studies examining foods naturally higher in RS are needed to understand microbiota changes in response to dietary intake of RS and associated health effects.

Gut Microbiome and Metabolome Variations in Self-Identified Muscle Builders Who Report Using Protein Supplements

Muscle builders frequently consume protein supplements, but little is known about their effect on the gut microbiota. This study compared the gut microbiome and metabolome of self-identified muscle builders who did or did not report consuming a protein supplement. Twenty-two participants (14 males and 8 females) consumed a protein supplement (PS), and seventeen participants (12 males and 5 females) did not (No PS). Participants provided a fecal sample and completed a 24-h food recall (ASA24). The PS group consumed significantly more protein (118 ± 12 g No PS vs. 169 ± 18 g PS, p = 0.02). Fecal metabolome and microbiome were analyzed by using untargeted metabolomics and 16S rRNA gene sequencing, respectively. Metabolomic analysis identified distinct metabolic profiles driven by allantoin (VIP score = 2.85, PS 2.3-fold higher), a catabolic product of uric acid. High-protein diets contain large quantities of purines, which gut microbes degrade to uric acid and then allantoin. The bacteria order Lactobacillales was higher in the PS group (22.6 ± 49 No PS vs. 136.5 ± 38.1, PS (p = 0.007)), and this bacteria family facilitates purine absorption and uric acid decomposition. Bacterial genes associated with nucleotide metabolism pathways (p < 0.001) were more highly expressed in the No PS group. Both fecal metagenomic and metabolomic analyses revealed that the PS group’s higher protein intake impacted nitrogen metabolism, specifically altering nucleotide degradation.

Grifola frondosa may play an anti-obesity role by affecting intestinal microbiota to increase the production of short-chain fatty acids

BACKGROUND

Grifola frondosa (G. frondosa) is a fungus with good economic exploitation prospects of food and medicine homologation. This study aims to investigate the effects of G. frondosa powder suspension (GFPS) on the intestinal contents microbiota and the indexes related to oxidative stress and energy metabolism in mice, to provide new ideas for developing G. frondosa weight loss products.

METHODS

Twenty Kunming mice were randomly divided into control (CC), low-dose GFPS (CL), medium-dose GFPS (CM), and high-dose GFPS (CH) groups. The mice in CL, CM, and CH groups were intragastrically administered with 1.425 g/(kg·d), 2.85 g/(kg·d), and 5.735 g/(kg·d) GFPS, respectively. The mice in CC group were given the same dose of sterile water. After 8 weeks, liver and muscle related oxidative stress and energy metabolism indicators were detected, and the intestinal content microbiota of the mice was detected by 16S rRNA high-throughput sequencing.

RESULTS

After eight weeks of GFPS intervention, all mice lost weight. Compared with the CC group, lactate dehydrogenase (LDH) and malondialdehyde (MDA) contents in CL, CM, and CH groups were increased, while Succinate dehydrogenase (SDH) and Superoxide Dismutase (SOD) contents in the liver were decreased. The change trends of LDH and SDH in muscle were consistent with those in the liver. Among the above indexes, the change in CH is the most significant. The Chao1, ACE, Shannon, and Simpson index in CL, CM, and CH groups were increased. In the taxonomic composition, after the intervention with GFPS, the short-chain fatty acid (SCFA)-producing bacteria such as unclassified Muribaculaceae, Alloprevotella, and unclassified Lachnospiraceae increased. In linear discriminant analysis effect size (LEfSe) analysis, the characteristic bacteria in CC, CL, CM, and CH groups showed significant differences. In addition, some characteristic bacteria significantly correlated with related energy metabolism indicators.

CONCLUSION

The preventive effect of G. frondosa on obesity is related to changing the structure of intestinal content microbiota and promoting the growth of SCFAs. While excessive intake of G. frondosa may not be conducive to the antioxidant capacity and energy metabolism.

The Gut Microbiome Is Associated with Circulating Dietary Biomarkers of Fruit and Vegetable Intake in a Multiethnic Cohort

BACKGROUND

Results from observational studies suggest high diet quality favorably influences the human gut microbiome. Fruit and vegetable consumption is often a key contributor to high diet quality.

OBJECTIVE

To evaluate measures of gut bacterial diversity and abundance in relation to serum biomarkers of fruit and vegetable intake.

DESIGN

Secondary analysis of cross-sectional data.

PARTICIPANTS AND SETTING

Men and women from Los Angeles, CA, and Hawai'i who participated in the Multiethnic Cohort-Adiposity Phenotype Study from 2013 to 2016 (N = 1,709).

MAIN OUTCOME MEASURES

Gut microbiome diversity and composition in relation to dietary biomarkers.

STATISTICAL ANALYSIS

Carotenoid (beta carotene, alpha carotene, cryptoxanthins, lutein, lycopene, and zeaxanthin), tocopherol (α, β + γ, and δ), and retinol concentrations were assessed in serum. The α and β diversity and composition of the gut microbiome were classified based on 16S rRNA gene sequencing of bacterial DNA from self-collected fecal samples. Global differences in microbial community profiles in relation dietary biomarkers were evaluated using multivariable permutational analysis of variance. Associations of α diversity (Shannon index), β diversity (weighted and unweighted UniFrac) with center log-ratio-transformed phyla and genera abundances were evaluated using linear regression, adjusted for covariates.

RESULTS

Increasing total carotenoid, beta carotene, alpha carotene, cryptoxanthin, and lycopene concentrations were associated with higher gut bacterial diversity (Shannon Index) (P < 0.001). Total tocopherol, α-tocopherol, and δ-tocopherol concentrations contributed significantly to more than 1% of the microbiome variation in gut bacterial community: total tocopherol: 1.74%; α-tocopherol: 1.70%; and δ-tocopherol: 1.16% (P < 0.001). Higher total carotenoid was associated with greater abundance of some genera relevant for microbial macronutrient metabolism (P < 0.001).

CONCLUSIONS

Objective biomarkers of fruit and vegetable intake, particularly carotenoids, were favorably associated with gut bacterial composition and diversity in this multiethnic population. These observations provide supportive evidence that fruit and vegetable intake is related to gut bacterial composition; more work is needed to elucidate how this influences host health.

Effect of Standardized Grape Powder Consumption on the Gut Microbiome of Healthy Subjects: A Pilot Study

Grapes provide a rich source of polyphenols and fibers. This study aimed to evaluate the effect of the daily consumption of 46 g of whole grape powder, providing the equivalent of two servings of California table grapes, on the gut microbiome and cholesterol/bile acid metabolism in healthy adults. This study included a 4-week standardization to a low-polyphenol diet, followed by 4 weeks of 46 g of grape powder consumption while continuing the low-polyphenol diet. Compared to the baseline, 4 weeks of grape powder consumption significantly increased the alpha diversity index of the gut microbiome. There was a trend of increasing Verrucomicrobia (p = 0.052) at the phylum level, and a significant increase in Akkermansia was noted. In addition, there was an increase in Flavonifractor and Lachnospiraceae_UCG-010, but a decrease in Bifidobacterium and Dialister at the genus level. Grape powder consumption significantly decreased the total cholesterol by 6.1% and HDL cholesterol by 7.6%. There was also a trend of decreasing LDL cholesterol by 5.9%, and decreasing total bile acid by 40.9%. Blood triglyceride levels and body composition were not changed by grape powder consumption. In conclusion, grape powder consumption significantly modified the gut microbiome and cholesterol/bile acid metabolism.

Lactobacillus johnsonii N6.2 and Blueberry Phytophenols Affect Lipidome and Gut Microbiota Composition of Rats Under High-Fat Diet

Obesity is considered a primary contributing factor in the development of many diseases, including cancer, diabetes, and cardiovascular illnesses. Phytochemical-rich foods, associated to healthy gastrointestinal microbiota, have been shown to reduce obesity and associated comorbidities. In the present article, we describe the effects of the probiotic Lactobacillus johnsonii N6.2 and blueberry extracts (BB) on the gut microbiota and lipid profile of rats under a high-fat (HF) or low-calorie (LC) diet. L. johnsonii was found to increase the levels of long chain fatty acids (LCFA) in the serum of all animals under HF diet, while reduced LCFA concentrations were observed in the adipose tissue of animals under HF diet supplemented with BB extracts. All animals under HF diet also showed lower protein levels of SREBP1 and SCAP when treated with L. johnsonii. The gut microbiota diversity, β-diversity was significantly changed by L. johnsonii in the presence of BB. A significant reduction in α-diversity was observed in the ileum of animals under HF diet supplemented with L. johnsonii and BB, while increased α-diversity was observed in the ilium of animals under LC diet supplemented with L. johnsonii or BB. In summary, L. johnsonii and BB supplementation induced significant changes in gut microbiota diversity and lipid metabolism. The phospholipids pool was the lipidome component directly affected by the interventions. The ileum and colon microbiota showed clear differences depending on the diet and the treatments examined.

An Intervention With Michigan-Grown Wheat in Healthy Adult Humans to Determine Effect on Gut Microbiota: Protocol for a Crossover Trial

BACKGROUND

Daily fiber intake can increase the diversity of the human gut microbiota as well as the abundance of beneficial microbes and their metabolites. Whole-grain wheat is high in fiber.

OBJECTIVE

This manuscript presents a study protocol designed to understand the effects of different types of wheat on gastrointestinal tract microbes.

METHODS

Human adults will consume crackers made from three types of wheat flour (refined soft white wheat, whole-grain soft white wheat, and whole-grain soft red wheat). In this study, participants will alternate between crackers made from refined soft white wheat flour to those made from whole-grain soft white wheat and whole-grain soft red wheat flour. Survey and stool sample collection will occur after 7-day treatment periods. We will assess how wheat consumption affects gastrointestinal bacteria by sequencing the V4 region of 16S rRNA gene amplicons and the inflammatory state of participants' intestines using enzyme-linked immunosorbent assays. The butyrate production capacity of the gut microbiota will be determined by targeted quantitative real-time polymerase chain reaction.

RESULTS

We will report the treatment effects on alpha and beta diversity of the microbiota and taxa-specific differences. Microbiota results will be analyzed using the vegan package in R. Butyrate production capacity and biomarkers of intestinal inflammation will be analyzed using parametric statistical methods such as analysis of variance or linear regression. We expect whole wheat intake to increase butyrate production capacity, bacterial alpha diversity, and abundance of bacterial taxa responsive to phenolic compounds. Soft red wheat is also expected to decrease the concentration of inflammatory biomarkers in the stool of participants.

CONCLUSIONS

This protocol describes the methods to be used in a study on the impact of wheat types on the human gastrointestinal microbiota and biomarkers of intestinal inflammation. The analysis of intestinal responses to the consumption of two types of whole wheat will expand our understanding of how specific foods affect health-associated outcomes.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/29046.

Adherence to Mediterranean diet impacts gastrointestinal microbial diversity throughout pregnancy

Background

Consumption of a diet with high adherence to a Mediterranean diet pattern (MDP) has been associated with a favorable gastrointestinal tract (GIT) microbiome. A healthy GIT microbiome in pregnancy, as defined by increased alpha diversity, is associated with lower chance of adverse perinatal outcomes. This study aimed to evaluate the impact of adherence to an MDP on GIT microbial diversity longitudinally throughout pregnancy.

Methods

Adherence to MDP was scored by the Alternate Mediterranean (aMED) Diet Quality Score, after being applied to a validated Food Frequency Questionnaire. Association of aMED Scores with GIT alpha diversity profiles were compared linearly and across time using a linear mixed model, including covariates of age, body mass index (BMI), ethnicity, and parity.

Results

Forty-one participants of Filipino, Japanese, Native Hawaiian, and Non-Hispanic White descent provided dietary information and microbiome samples during each trimester of pregnancy. Alpha diversity profiles changed over gestation, with decreased microbial diversity in the third trimester. aMED scores positively correlated with Chao1 Index and Observed Species Number (r = 0.244, p = 0.017, and r = 0.233, p = 0.023, respectively). The strongest association was detected in the third trimester (Chao 1: r = 0.43, p = 0.020, Observed Species Number: r = 0.41, p = 0.026). Participants with higher aMED scores had higher relative abundance of Acidaminoacaeae at the family level (p = 0.0169), as well as higher abundance of several species known to increase production of short chain fatty acids within the GIT.

Conclusions

Adherence to MDP pattern is associated with increased maternal GIT microbial diversity, and promotes the abundance of bacteria that produce short chain fatty acids. Increased consumption of fruits, vegetables and legumes with low red meat consumption were key components driving this association. The effect of nutrition however, was less of an effect than pregnancy itself. Further studies are needed to determine if adherence to a Mediterranean diet translates not only into microbial health, but also into reduced risk of adverse pregnancy outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04033-8.

Long-term association between diet quality and characteristics of the gut microbiome in the multiethnic cohort study

As past usual diet quality may affect gut microbiome (GM) composition, we examined the association of the Healthy Eating Index (HEI)-2015 assessed 21 and 9 years before stool collection with measures of fecal microbial composition in a subset of the Multiethnic Cohort. A total of 5936 participants completed a validated quantitative FFQ (QFFQ) at cohort entry (Q1, 1993-1996), 5280 at follow-up (Q3, 2003-2008) and 1685 also at a second follow-up (Adiposity Phenotype Study (APS), 2013-2016). All participants provided a stool sample in 2013-2016. Fecal microbial composition was obtained from 16S rRNA gene sequencing (V1-V3 regions). HEI-2015 scores were computed based on each QFFQ. Using linear regression adjusted for relevant covariates, we calculated associations of HEI-2015 scores with gut microbial diversity and 152 individual genera. The mean HEI-2015 scores increased from Q1 (67 (sd 10)) to Q3 (71 (sd 11)) and APS (72 (sd 10)). Alpha diversity assessed by the Shannon Index was significantly higher with increasing tertiles of HEI-2015. Of the 152 bacterial genera tested, seven (Anaerostipes, Coprococcus_2, Eubacterium eligens, Lachnospira, Lachnospiraceae_ND3007, Ruminococcaceae_UCG-013 and Ruminococcus_1) were positively and five (Collinsella, Parabacteroides, Ruminiclostridium_5, Ruminococcus gnavus and Tyzzerella) were inversely associated with HEI-2015 assessed in Q1, Q3 and APS. The estimates of change per unit of the HEI-2015 score associated with the abundance of these twelve genera were consistent across the three questionnaires. The quality of past diet, assessed as far as ∼20 years before stool collection, is equally predictive of GM composition as concurrently assessed diet, indicative of the long-term consistency of this relation.

Infants' First Solid Foods: Impact on Gut Microbiota Development in Two Intercontinental Cohorts

The introduction of solid foods is an important dietary event during infancy that causes profound shifts in the gut microbial composition towards a more adult-like state. Infant gut bacterial dynamics, especially in relation to nutritional intake remain understudied. Over 2 weeks surrounding the time of solid food introduction, the day-to-day dynamics in the gut microbiomes of 24 healthy, full-term infants from the Baby, Food & Mi and LucKi-Gut cohort studies were investigated in relation to their dietary intake. Microbial richness (observed species) and diversity (Shannon index) increased over time and were positively associated with dietary diversity. Microbial community structure (Bray-Curtis dissimilarity) was determined predominantly by individual and age (days). The extent of change in community structure in the introductory period was negatively associated with daily dietary diversity. High daily dietary diversity stabilized the gut microbiome. Bifidobacterial taxa were positively associated, while taxa of the genus Veillonella, that may be the same species, were negatively associated with dietary diversity in both cohorts. This study furthers our understanding of the impact of solid food introduction on gut microbiome development in early life. Dietary diversity seems to have the greatest impact on the gut microbiome as solids are introduced.