Associations between UK tap water and gut microbiota composition suggest the gut microbiome as a potential mediator of health differences linked to water quality

Cytidine Alleviates Dyslipidemia and Modulates the Gut Microbiota Composition in ob/ob Mice

Cytidine and uridine are endogenous metabolites in the pyrimidine metabolism pathway, and cytidine is a substrate that can be metabolized into uridine via cytidine deaminase. Uridine has been widely reported to be effective in regulating lipid metabolism. However, whether cytidine could ameliorate lipid metabolism disorder has not yet been investigated. In this research, ob/ob mice were used, and the effect of cytidine (0.4 mg/mL in drinking water for five weeks) on lipid metabolism disorder was evaluated in terms of an oral glucose tolerance test, serum lipid levels, liver histopathological analysis and gut microbiome analysis. Uridine was used as a positive control. Our findings reveal that cytidine could alleviate certain aspects of dyslipidemia and improve hepatic steatosis via modulating the gut microbiota composition in ob/ob mice, especially increasing the abundance of short-chain fatty acids-producing microbiota. These results suggest that cytidine supplementation could be a potential therapeutic approach for dyslipidemia.

Mechanisms of the intestinal and urinary microbiome in kidney stone disease

Kidney stone disease affects ~10% of the global population and the incidence continues to rise owing to the associated global increase in the incidence of medical conditions associated with kidney stone disease including, for example, those comprising the metabolic syndrome. Considering that the intestinal microbiome has a substantial influence on host metabolism, that evidence has suggested that the intestinal microbiome might have a role in maintaining oxalate homeostasis and kidney stone disease is unsurprising. In addition, the discovery that urine is not sterile but, like other sites of the human body, harbours commensal bacterial species that collectively form a urinary microbiome, is an additional factor that might influence the induction of crystal formation and stone growth directly in the kidney. Collectively, the microbiomes of the host could influence kidney stone disease at multiple levels, including intestinal oxalate absorption and direct crystal formation in the kidneys.

Tap water as a natural vehicle for microorganisms shaping the human gut microbiome

Fresh potable water is an indispensable drink which humans consume daily in substantial amounts. Nonetheless, very little is known about the composition of the microbial community inhabiting drinking water or its impact on our gut microbiota. In the current study, an exhaustive shotgun metagenomics analysis of the tap water microbiome highlighted the occurrence of a highly genetic biodiversity of the microbial communities residing in fresh water and the existence of a conserved core tap water microbiota largely represented by novel microbial species, representing microbial dark matter. Furthermore, genome reconstruction of this microbial dark matter from water samples unveiled homologous sequences present in the faecal microbiome of humans from various geographical locations. Accordingly, investigation of the faecal microbiota content of a subject that daily consumed tap water for 3 years provides proof for horizontal transmission and colonization of water bacteria in the human gut.

Microbial Kin: Relations of Environment and Time

Microbiome science considers human beings supraorganisms: single ecological units made up of symbiotic assemblages of human cells and microorganisms. Microbes co-evolve with humans, and microbial populations in human bodies are determined by environments/exposures including family, food and place, health care, race and gender inequities, and toxic pollution. Microbiomes are transgenerational links, disarrangements between different bodies and the outside world. This article asserts that microbes are kin-kin that are made of and making environments, across generations. Post/nonhuman theories have debated the agency, sociality, and ontologies of microbes and things like microbes, all the while appropriating and eliding Indigenous scholarship that directly address the nonhuman world. Microbial kin evokes Indigenous formulations that necessitate reciprocal, ethical accountability to more-than-human relations. This article uses fieldwork in a transnational microbiome malnutrition project in Bangladesh to explore what develops for both the biological and social sciences if we call human-microbe relations kinships, and call microbes our kin.

Association of Consuming Tap Water or Purified Water during Infancy with Irritable Bowel Syndrome in Children

Objective: The objective of this study was to analyze the effect of consuming formula powder prepared with tap water or purified water during the first 4 to 6 months of life on the subsequent development of irritable bowel syndrome (IBS). Study design and setting: A total of 917,707 children who were born in Korea between 2007 and 2008 were analyzed. All children were followed up until they lost eligibility for health care services or until 2017. Data on the water used to prepare formula powder were from questionnaires answered by the parents when the child was 4 to 6 months old. IBS was defined as two or more diagnoses of IBS after the age of 4 years. Inverse probability of treatment weighting (IPTW) using the propensity score was used to balance the two groups. The risk of IBS was evaluated using a Cox proportional hazards model. Results: After weighting, there were 73,355 children in the tap water group and 73,351 in the purified water group. The purified water group had a higher risk of IBS (HR: 1.05; 95% CI: 1.01, 1.09). This relationship was also present after the subgroup analyses of males and females and the sensitivity analysis that used different definitions of IBS. Conclusions: Drinking formula powder prepared with purified water rather than tap water during the first 4 to 6 months of age was found to be associated with IBS.

Water Security and Nutrition: Current Knowledge and Research Opportunities

Water is an essential nutrient that has primarily been considered in terms of its physiological necessity. But reliable access to water in sufficient quantities and quality is also critical for many nutrition-related behaviors and activities, including growing and cooking diverse foods. Given growing challenges to water availability and safety, including climate change, pollution, and infrastructure degradation, a broader conceptualization of water and its diverse uses is needed to sustainably achieve global nutrition targets. Therefore, we review empirical and qualitative evidence describing the linkages between water security (the reliable availability, accessibility, and quality of water for all household uses) and nutrition. Primary linkages include water security for drinking, food production and preparation, infant and young child feeding, and limiting exposure to pathogens and environmental toxins. We then identify knowledge gaps within each linkage and propose a research agenda for studying water security and nutrition going forward, including the concurrent quantification of both food and water availability, accessibility, use, and stability. By making explicit the connections between water security and nutritional well-being, we aim to promote greater collaboration between the nutrition and water, sanitation, and hygiene sectors. Interdisciplinary policies and programs that holistically address the water-nutrition nexus, versus those that focus on water and nutrition independently, are likely to significantly advance our ability to ensure equitable access to healthy foods and safe water for all.

Drinking Water Source and Intake Are Associated with Distinct Gut Microbiota Signatures in US and UK Populations

BACKGROUND

The microbiome of the digestive tract exerts fundamental roles in host physiology. Extrinsic factors including lifestyle and diet are widely recognized as key drivers of gut and oral microbiome compositions. Although drinking water is among the food items consumed in the largest amount, little is known about its potential impact on the microbiome.

OBJECTIVES

We explored the associations of plain drinking water source and intake with gut and oral microbiota compositions in a population-based cohort.

METHODS

Microbiota, health, lifestyle, and food intake data were extracted from the American Gut Project public database. Associations of drinking water source (bottled, tap, filtered, or well water) and intake with global microbiota composition were evaluated using linear and logistic models adjusted for anthropometric, diet, and lifestyle factors in 3413 and 3794 individuals, respectively (fecal samples; 56% female, median [IQR] age: 48 [36-59] y; median [IQR] BMI: 23.3 [20.9-26.3] kg/m2), and in 283 and 309 individuals, respectively (oral samples).

RESULTS

Drinking water source ranked among the key contributing factors explaining the gut microbiota variation, accounting for 13% [Faith's phylogenetic diversity (Faith's PD)] and 47% (Bray-Curtis dissimilarity) of the age effect size. Drinking water source was associated with differences in gut microbiota signatures, as revealed by β diversity analyses (P < 0.05; Bray-Curtis dissimilarity, weighted UniFrac distance). Subjects drinking mostly well water had higher fecal α diversity (P < 0.05; Faith's PD, observed amplicon sequence variants), higher Dorea, and lower Bacteroides, Odoribacter, and Streptococcus than the other groups. Low water drinkers also exhibited gut microbiota differences compared with high water drinkers (P < 0.05; Bray-Curtis dissimilarity, unweighted UniFrac distance) and a higher abundance of Campylobacter. No associations were found between oral microbiota composition and drinking water consumption.

CONCLUSIONS

Our results indicate that drinking water may be an important factor in shaping the human gut microbiome and that integrating drinking water source and intake as covariates in future microbiome analyses is warranted.

Pollution, Inflammation, and Vaccines: A Complex Crosstalk

The importance of pollution in determining human health is becoming increasingly clear, also given the dramatic consequences it has had on recent geopolitical events. Yet, the consequences of contamination are not always straightforward. In this paper, we will discuss the effects of different pollutants on different aspects of human health, in particular on the immune system and inflammation. Different environmental pollutants can have different effects on the immune system, which can then promote complex pathologies, such as autoimmune disorders and cancer. The interaction with the microbiota also further helps to determine the consequences of contamination on wellbeing. The pollution can affect vaccination efficacy, given the widespread effects of vaccination on immunity. At the same time, some vaccinations also can exert protective effects against some forms of pollution.

Associations between Drinking Water Source and Gut Microbiota Composition in the American Gut Project Database

INTRODUCTION

The gut microbiome exerts a fundamental role in host physiology. Extrinsic factors such as lifestyle and diet are widely recognized as the main drivers of gut microbiota composition [<xref ref-type="bibr" rid="ref1">1</xref>, <xref ref-type="bibr" rid="ref2">2</xref>]. While drinking water is among the food items consumed in the largest amount, little is known about its potential impact on gut microbiota structures [<xref ref-type="bibr" rid="ref3">3</xref>-<xref ref-type="bibr" rid="ref5">5</xref>].

OBJECTIVE

We explored the associations between plain drinking water source and gut microbiota compositions in a large microbiota-based cohort.

METHODS

Participants in the American Gut Project database provided fecal samples and completed health, lifestyle, and food records which included plain drinking water source (bottled, tap, filtered, or well water). Associations between drinking water source and gut microbiota were evaluated using models adjusted for anthropometric, diet, and lifestyle factors in 3,413 individuals [<xref ref-type="bibr" rid="ref6">6</xref>]. Index of intra-individual fecal microbial diversity, inter-individual differences in composition, and taxa abundance were estimated by 16S rRNA sequencing.

RESULTS

The type of drinking water was associated with fecal microbiota composition. Drinking water source ranked among the key contributing factor explaining the gut microbiota variation both in alpha and beta diversity analyses, with effect sizes comparable to that of alcohol or diet type [<xref ref-type="bibr" rid="ref6">6</xref>] (Fig. <xref ref-type="fig" rid="f01">1</xref>). Subjects drinking different sources of water had differences in gut microbiota signatures, as revealed by beta diversity analyses (p < 0.05; Bray-Curtis dissimilarity, Weighted UniFrac distance) [<xref ref-type="bibr" rid="ref6">6</xref>]. Subjects drinking mostly well water also had higher fecal alpha diversity than the other groups (p < 0.05; Faith's PD, Observed OTUs) [<xref ref-type="bibr" rid="ref6">6</xref>]. Taxonomic differences were found in well water drinkers, with clinically important taxa, such as Bacteroides, Odoribacter, and Streptococcus being depleted and Dorea being increased as compared to the other groups [6].

CONCLUSIONS

Our results reveal that drinking water may be an important factor in shaping the gut microbiome. Future research investigating the gut microbiota in relation to environmental factors may benefit from integrating drinking water source as a covariate in the analyses.