Evaluating the effects of corn flour product consumption on cardio-metabolic outcomes and the gut microbiota in adults with elevated cholesterol: A randomized Crossover.

BACKGROUND: Consumption of whole grains is associated with a reduction in chronic diseases and offers benefits for cardiovascular health and metabolic regulation. The relationship between whole grain corn and corn bran with the gut microbiota (GM) remains an area of growing interest, particularly regarding their influence on cardio-metabolic health. OBJECTIVE: To investigate the effects of different corn flours on cardio-metabolic outcomes and GM changes in adults with elevated low-density lipoprotein cholesterol (LDL-c) concentrations. METHODS: In this crossover study, 36 adults with LDL-c above 110 mg/dL consumed 48 g/day of three corn flour types for four weeks: whole-grain corn meal (WCM), refined corn meal (RCM), and a blend of RCM and corn bran (RCM+B). We assessed the impact on cardio-metabolic markers (LDL-c, high-density lipoprotein cholesterol [HDL-c], total cholesterol [TC], and triglycerides [TG]) and GM composition and estimated function. Statistical analyses included mixed-effects modeling and responder (> 5% decrease in LDL-c) analysis to evaluate changes in GM related to lipid profile improvements. RESULTS: Of the three corn flour types, only RCM+B significantly decreased LDL-c over time (-10.4±3.6 mg/dL, P = 0.005) and marginally decreased TC (-9.2±3.9, P = 0.072) over time. There were no significant effects on HDL-c or TG concentrations. No significant changes were observed in GM alpha diversity, while beta diversity metrics indicated individual variability. Two genera, unclassified Lachnospiraceae and Agathobaculum (Padj ≤ 0.096), differed significantly by treatment, but only Agathobaculum remained significantly elevated in the WCM, compared to RCM and RCM+B, after adjustment for multiple comparisons. CONCLUSIONS: The type of corn flour, particularly RCM+B, notably influenced LDL-c concentrations in adults with elevated LDL-c. This study suggests that incorporating milled fractions (e.g. bran) of whole grain corn with refined corn flour may be a viable alternative to supplementing manufactured grain products with isolated or synthetic fibers for improved metabolic health. CLINICALTRIALS: gov ID: NCT03967990.

Identifying Gut Microbiome Features that Predict Responsiveness Toward a Prebiotic Capable of Increasing Calcium Absorption: A Pilot Study.

Previously, we demonstrated that prebiotics may provide a complementary strategy for increasing calcium (Ca) absorption in adolescents which may improve long-term bone health. However, not all children responded to prebiotic intervention. We determine if certain baseline characteristics of gut microbiome composition predict prebiotic responsiveness. In this secondary analysis, we compared differences in relative microbiota taxa abundance between responders (greater than or equal to 3% increase in Ca absorption) and non-responders (less than 3% increase). Dual stable isotope methodologies were used to assess fractional Ca absorption at the end of crossover treatments with placebo, 10, and 20 g/day of soluble corn fiber (SCF). Microbial DNA was obtained from stool samples collected before and after each intervention. Sequencing of the 16S rRNA gene was used to taxonomically characterize the gut microbiome. Machine learning techniques were used to build a predictive model for identifying responders based on baseline relative taxa abundances. Model output was used to infer which features contributed most to prediction accuracy. We identified 19 microbial features out of the 221 observed that predicted responsiveness with 96.0% average accuracy. The results suggest a simplified prescreening can be performed to determine if a subject's bone health may benefit from a prebiotic. Additionally, the findings provide insight and prompt further investigation into the metabolic and genetic underpinnings affecting calcium absorption during pubertal bone development.

Actigraphic sleep patterns are associated with bone turnover and bone mineral density among university students.

Poorer sleep is associated with poorer bone health among older adults but the role of sleep in bone health during younger adulthood is understudied. In this observational study, the averages and variability in total sleep time (TST), sleep efficiency (SE), and sleep midpoint of university students were examined in relation to levels of bone turnover markers (BTMs) and bone mineral density (BMD) at the lumbar spine and femur. A sample of healthy, university students (N = 59, aged 18-25 years, 51.8% female, body mass index <30 kg/m2 ), wore a wrist actigraph for 7 days, completed a dual-energy X-ray absorptiometry scan, and underwent blood sampling to assess serum BTM concentrations of osteocalcin (OC) and N-terminal telopeptide of type 1 collagen. A sub-sample (n = 14) completed a one-year follow-up. Multiple regression models examined the associations between each sleep metric and bone health outcome at baseline and 1-year follow-up. At baseline, greater variability in sleep midpoint was cross-sectionally associated with greater OC (ß = 0.21, p = 0.042). In the exploratory, follow-up sub-sample, lower average TST (ß = -0.66, p = 0.013) and SE (ß = -0.68, p = 0.01) at baseline were associated with greater increases in OC at follow-up. Greater delays in mean sleep midpoint over follow-up were significantly associated with decreases in lumbar spine BMD (ß = -0.49, p = 0.03). In a sample of young adults, variable sleep schedules were associated with greater bone turnover suggesting the potential importance of regular sleep for optimising bone health into early adulthood.

A New American University Model for Training the Future MCH Workforce Through a Translational Research Team.

OBJECTIVES: To describe the process of developing and implementing experiential learning through translational research teams that engage diverse undergraduate and graduate students. METHODS: After a college redesign, translational research teams were developed to foster multidisciplinary research and better integrate students with faculty research, community, and clinical activities. Three primary approaches were used to engage undergraduate and graduate students in the maternal and child health translational research team (MCH TrT). These included an undergraduate experiential learning course; participation in translational research team meetings and events; and mentorship activities including graduate student theses and supplementary projects. RESULTS: Since 2019, a total of 56 students have engaged with the MCH translational research team. The majority (64%) of students engaging in translational research were undergraduates. Racial and ethnic diversity was evident with 16% Latinx, 14% Black/African American, 12% Asian, 10% two or more races, and 4% Native American or Native Hawaiian. A large proportion (42%) of students indicated that they were first-generation college students, while 24% indicated they had a disability. Five themes emerged from student feedback about their involvement in the experiential learning course: the value of translational research, development of research skills, collaboration, practice development, and value for community partners. CONCLUSIONS FOR PRACTICE: Through an MCH translational research team, we have established a pathway to enhance diversity among the MCH workforce which will increase recruitment and retention of underrepresented groups, and ultimately improve MCH research and practice.

Protocol of the Snuggle Bug/Acurrucadito Study: a longitudinal study investigating the influences of sleep-wake patterns and gut microbiome development in infancy on rapid weight gain, an early risk factor for obesity.

BACKGROUND: Overweight, obesity, and associated comorbidities are a pressing global issue among children of all ages, particularly among low-income populations. Rapid weight gain (RWG) in the first 6 months of infancy contributes to childhood obesity. Suboptimal sleep-wake patterns and gut microbiota (GM) have also been associated with childhood obesity, but little is known about their influences on early infant RWG. Sleep may alter the GM and infant metabolism, and ultimately impact obesity; however, data on the interaction between sleep-wake patterns and GM development on infant growth are scarce. In this study, we aim to investigate associations of infant sleep-wake patterns and GM development with RWG at 6 months and weight gain at 12 months. We also aim to evaluate whether temporal interactions exist between infant sleep-wake patterns and GM, and if these relations influence RWG. METHODS: The Snuggle Bug/ Acurrucadito study is an observational, longitudinal study investigating whether 24-h, actigraphy-assessed, sleep-wake patterns and GM development are associated with RWG among infants in their first year. Based on the Ecological Model of Growth, we propose a novel conceptual framework to incorporate sleep-wake patterns and the GM as metabolic contributors for RWG in the context of maternal-infant interactions, and familial and socio-physical environments. In total, 192 mother-infant pairs will be recruited, and sleep-wake patterns and GM development assessed at 3 and 8 weeks, and 3, 6, 9, and 12 months postpartum. Covariates including maternal and child characteristics, family and environmental factors, feeding practices and dietary intake of infants and mothers, and stool-derived metabolome and exfoliome data will be assessed. The study will apply machine learning techniques combined with logistic time-varying effect models to capture infant growth and aid in elucidating the dynamic associations between study variables and RWG. DISCUSSION: Repeated, valid, and objective assessment at clinically and developmentally meaningful intervals will provide robust measures of longitudinal sleep, GM, and growth. Project findings will provide evidence for future interventions to prevent RWG in infancy and subsequent obesity. The work also may spur the development of evidence-based guidelines to address modifiable factors that influence sleep-wake and GM development and prevent childhood obesity.

Diet, physical activity and screen time but not body mass index are associated with the gut microbiome of a diverse cohort of college students living in university housing: a cross-sectional study.

BACKGROUND: Modifiable lifestyle factors (e.g. dietary intake and physical activity) are important contributors to weight gain during college. The purpose of this study was to evaluate whether associations exist between body mass index, physical activity, screen time, dietary consumption (fat, protein, carbohydrates, and fiber), and gut microbial diversity during the first year of college. Racially/ethnically diverse college students (n = 82; 61.0% non-white) at a large Southwestern university completed self-reported physical activity and 24-h recall dietary assessments, height and weight measurements, and provided one fecal sample for gut microbiome analysis. Fecal microbial community composition was assessed with Illumina MiSeq next-generation sequencing of PCR amplified 16S rRNA genes. Post-hoc analyses compared microbial diversity by groups of high and low physical activity and fiber intake using QIIME and LEfSe bioinformatics software. RESULTS: No statistically significant differences were observed between body mass index and gut microbiome abundance and diversity. Median daily consumption of dietary fiber was 11.2 (7.6, 14.9) g/d, while the median self-reported moderate-to-vigorous physical activity (MVPA) was 55.7 (27.9, 79.3) min/d and screen time 195.0 (195.0, 315.0) min/d. Microbial analysis by LEfSe identified Paraprevotellaceae, Lachnospiraceae, and Lachnospira as important phylotypes in college students reporting greater MVPA, while Enterobacteriaceae and Enterobacteriales were more enriched among students reporting less MVPA (p < 0.05). Barnesiellaceae, Alphaproteobacteria, and Ruminococcus were more abundant taxa among those consuming less than the median fiber intake (p < 0.05). Post-hoc analyses comparing weighted UniFrac distance metrics based on combined categories of high and low MVPA and fiber revealed that clustering distances between members of the high MVPA-low fiber group were significantly smaller when compared to distances between members of all other MVPA-fiber groups (p < 0.0001). CONCLUSIONS: Habitual fiber consumption and MVPA behaviors help explain the differential abundance of specific microbial taxa and overall gut microbial diversity differences in first-year college students.

Prebiotics, Bone and Mineral Metabolism.

Increasing interest in functional foods has driven discovery in the area of bioactive compounds. Prebiotics are non-digestible carbohydrate compounds that, when consumed, elicit health benefits and aid in the prevention and treatment of chronic diseases. While prebiotics have been shown to improve a number of chronic, inflammatory conditions, growing evidence exists for prebiotic effects on calcium metabolism and bone health. These novel dietary fibers have been shown to increase calcium absorption in the lower intestines of both preclinical and human models. Rodent models have also been imperative for understanding prebiotic effects on bone mineral density and measures of skeletal strength. Although fewer data are available for humans, bone-related prebiotic effects exist across the lifecycle, suggesting benefits for attainment of peak bone mass during adolescence and minimized bone resorption among postmenopausal women. These effects are thought to occur through prebiotic-microbe interactions in the large intestine. Current prebiotic mechanisms for improved mineral absorption and skeletal health include alterations in gut microbiota composition, production of short-chain fatty acids, altered intestinal pH, biomarker modification, and immune system regulation. While the majority of available data support improved mineral bioavailability, emerging evidence suggests alternate microbial roles and the presence of an intricate gut-bone signaling axis. Overall, the current scientific literature supports prebiotic consumption as a cost-effective and sustainable approach for improved skeletal health and/or fracture prevention. The goal of this review is to discuss both foundational and recent research in the area of prebiotics, mineral metabolism, and bone health.

Prebiotics and Bone.

Recent advancements in food science have resulted in the extraction and synthesis of novel dietary fibers or prebiotics. Subsequently, great interest has emerged in developing strategies to improve metabolic conditions like osteoporosis by modulating the intestinal microbiome with fiber. Prebiotics have been shown to increase calcium absorption in the lower gut of both animals and humans as well as improve measures of bone mineral density and strength in rodent models. Fewer data are available in humans, but data from growing children and postmenopausal women suggest that prebiotics have both short- and long-term effects that beneficially affect bone turnover and mineral accretion in the skeleton. Currently, the exact mechanism by which these products elicit their effects on bone is poorly understood, but emerging data suggest that the gut microbiota may be involved in one or more direct and indirect pathways. The most well-accepted mechanism is through microbial fermentation of prebiotics which results in the production of short-chain fatty acids and a concomitant decrease in pH which increases the bioavailability of calcium in the colon. While other mechanisms may be eliciting a prebiotic effect on bone, the current data suggest that novel dietary fibers may be an affordable and effective method of maximizing mineral accretion in growing children and preventing bone loss in later years when osteoporosis is a greater risk. This chapter will discuss the dynamic role of prebiotics in bone health by discussing the current state of the art, addressing gaps in knowledge and their role in public health.

Soluble Corn Fiber Increases Calcium Absorption Associated with Shifts in the Gut Microbiome: A Randomized Dose-Response Trial in Free-Living Pubertal Females.

BACKGROUND: Soluble corn fiber (SCF; 12 g fiber/d) is shown to increase calcium absorption efficiency, associated with shifts in the gut microbiota in adolescent males and females who participated in a controlled feeding study. OBJECTIVE: We evaluated the dose response of 0, 10, and 20 g fiber/d delivered by PROMITOR SCF 85 (85% fiber) on calcium absorption, biochemical bone properties, and the fecal microbiome in free-living adolescents. METHODS: Healthy adolescent females (n = 28; aged 11-14 y) randomly assigned into a 3-phase, double-blind, crossover study consumed SCF for 4 wk at each dose (0, 10, and 20 g fiber/d from SCF) alongside their habitual diet and were followed by 3-d clinical visits and 3-wk washout periods. Stable isotope ((44)Ca and (43)Ca) enrichment in pooled urine was measured by inductively coupled plasma mass spectrometry. Fecal microbial community composition was assessed by high-throughput sequencing (Illumina) of polymerase chain reaction-amplified 16S rRNA genes. Mixed model ANOVA and Friedman analysis were used to determine effects of SCF on calcium absorption and to compare mean microbial proportions, respectively. RESULTS: Calcium absorption increased significantly with 10 (13.3% ± 5.3%; P = 0.042) and 20 g fiber/d (12.9% ± 3.6%; P = 0.026) from SCF relative to control. Significant differences in fecal microbial community diversity were found after consuming SCF (operational taxonomic unit measures of 601.4 ± 83.5, 634.5 ± 83.8, and 649.6 ± 75.5 for 0, 10, and 20 g fiber/d, respectively; P < 0.05). Proportions of the genus Parabacteroides significantly increased with SCF dose (1.1% ± 0.8%, 2.1% ± 1.6%, and 3.0% ± 2.0% for 0, 10, and 20 g fiber/d from SCF, respectively; P < 0.05). Increases in calcium absorption positively correlated with increases in Clostridium (r = 0.44, P = 0.023) and unclassified Clostridiaceae (r = 0.40, P = 0.040). CONCLUSIONS: SCF, a nondigestible carbohydrate, increased calcium absorption in free-living adolescent females. Two groups of bacteria may be involved, one directly fermenting SCF and the second fermenting SCF metabolites further, thereby promoting increased calcium absorption. This trial was registered at clinicaltrials.gov as NCT01660503.

Longitudinal social networks impacts on weight and weight-related behaviors assessed using mobile-based ecological momentary assessments: Study Protocols for the SPARC study.

BACKGROUND: The transition from the home to college is a phase in which emerging adults shift toward more unhealthy eating and physical activity patterns, higher body mass indices, thus increasing risk of overweight/obesity. Currently, little is understood about how changing friendship networks shape weight gain behaviors. This paper describes the recruitment, data collection, and data analytic protocols for the SPARC (Social impact of Physical Activity and nutRition in College) study, a longitudinal examination of the mechanisms by which friends and friendship networks influence nutrition and physical activity behaviors and weight gain in the transition to college life. METHODS: The SPARC study aims to follow 1450 university freshmen from a large university over an academic year, collecting data on multiple aspects of friends and friendship networks. Integrating multiple types of data related to student lives, ecological momentary assessments (EMAs) are administered via a cell phone application, devilSPARC. EMAs collected in four 1-week periods (a total of 4 EMA waves) are integrated with linked data from web-based surveys and anthropometric measurements conducted at four times points (for a total of eight data collection periods including EMAs, separated by ~1 month). University databases will provide student card data, allowing integration of both time-dated data on food purchasing, use of physical activity venues, and geographical information system (GIS) locations of these activities relative to other students in their social networks. DISCUSSION: Findings are intended to guide the development of more effective interventions to enhance behaviors among college students that protect against weight gain during college.

Soluble maize fibre affects short-term calcium absorption in adolescent boys and girls: a randomised controlled trial using dual stable isotopic tracers.

Soluble maize fibre (SCF) has been found to significantly improve bone mineral density and strength in growing rats compared with several other novel prebiotic fibres. The objective of the present study was to investigate the effect of SCF on Ca absorption and retention in pubertal children by studying the potential absorption mechanisms of the intestinal microbiota. A total of twenty-four adolescent boys and girls (12-15 years) participated in two 3-week metabolic balance studies testing 0 g/d SCF (control (CON) treatment) and 12 g/d SCF (SCF treatment) in a random order by inclusion in a low-Ca diet (600 mg/d). Fractional Ca absorption was measured at the end of the two intervention periods using a dual-stable isotope method. Diet composites and faecal and urine samples were collected daily and analysed for Ca content. Ca retention was calculated as dietary Ca intake minus Ca excretion in faeces and urine over the last 2 weeks. Microbial community composition in the faecal samples collected at the beginning and end of each session was determined by 454 pyrosequencing of the PCR-amplified 16S ribosomal RNA gene. Fractional Ca absorption was 12 % higher (41 mg/d) after the SCF treatment compared with that after the CON treatment (0·664 (sd 0·129) and 0·595 (sd 0·142), respectively; P= 0·02), but Ca retention was unaffected. The average proportion of bacteria of the phylum Bacteroidetes was significantly greater in the participants after the SCF treatment than after the CON treatment. These results suggest that moderate daily intake of SCF, a well-tolerated prebiotic fibre, increases short-term Ca absorption in adolescents consuming less than the recommended amounts of Ca.

Omega-3 eicosapentaenoic polar-lipid rich extract from microalgae Nannochloropsis decreases plasma triglycerides and cholesterol in a real-world normolipidemic supplement consumer population.

Introduction: AlmegaPL® is an oil rich in polar-lipid (> 15% w/w) derived from the microalga Nannochloropsis, that contains exclusively eicosapentaenoic acid (EPA > 25% w/w), without the DHA that is present in all other natural sources of omega-3. Previous findings from a randomized controlled clinical trial demonstrated the ability of AlmegaPL® supplementation to reduce cholesterol levels. Methods: In this post-market cohort study, we built upon previous findings and targeted the actual end-users of the supplement. Participants were recruited from a new subscriber database of AlmegaPL® capsules (1000-1100 mg/day) to capture the complexity of real-world clinical and consumer settings. Changes in circulating triglycerides (TG), remnant cholesterol (RC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol (TC), high-sensitivity C-reactive protein (hs-CRP), glucose and glycated hemoglobin (HbA1c) were monitored at baseline, Month 3, and Month 6 of supplementation using the at-home Baseline Heart Health Testing Kit by Imaware® (Houston, TX, USA). Results: Participants, who had, on average, normal TG level at baseline (1.62 ± 0.60 mmol/L), experienced a significant and progressive decrease in TG at Month 3 (8.0%; -0.13 ± 0.59 mmol/L; p < 0.001) and Month 6 (14.2%; -0.23 ± 0.64 mmol/L; p < 0.001) (primary outcome). Furthermore, after 6 months of supplementation, TC and non-HDL-cholesterol decreased by 5.0% (-0.26 ± 0.98 mmol/L; p < 0.001) and 5.5% (-0.21 ± 0.86 mmol/L; p < 0.001) respectively, primarily driven by a 14.9% reduction in RC (-0.11 ± 0.29 mmol/L; p < 0.001). Discussion: Consistent with our previous clinical trial, the decrease in RC was not coupled to an increase in LDL, which seems to be a benefit associated with EPA-only based formulations. In addition, this study demonstrated the AlmegaPL® capacity to maintain already healthy TG levels by further inducing a 14.9% decrease. Collectively, these findings highlight AlmegaPL® uniqueness as a natural over-the-counter option for EPA-only polar lipid that appears particularly effective in maintaining blood lipid levels in a generally healthy, normolipidemic population. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05267301.

Sleep Disturbances and Hygiene of Adolescent Female Survivors of Domestic Minor Sex Trafficking.

INTRODUCTION: This cross-sectional quantitative study investigated the sleep hygiene and disturbances of adolescent female survivors of domestic minor sex trafficking (DMST) compared to an online sample of community-dwelling adolescent females. METHOD: Community-dwelling adolescent females (aged 13-17 years, n = 61) and survivors of DMST housed in residental care (aged 12-17 years, n = 19) completed the Children's Report of Sleep Patterns (adolescent version). Descriptive statistics on sleep health in both samples were computed and compared using chi-square and t-tests. RESULTS: Among the survivors of DMST, the majority reported insufficient sleep duration, okay-to-poor sleep quality, waking thirsty, and frequent nightmares. Compared with community-dwelling adolescents, survivors of DMST had more symptoms of insomnia, sleepiness, nightmares, and waking thirsty (p < .05). DISCUSSION: Sleep disturbances among adolescent female survivors of DMST may be more prevalent than in community-dwelling adolescent females. Further empirical research on appropriate assessment and trauma-informed treatment of sleep in this population is needed.

Associations of Infant Feeding, Sleep, and Weight Gain with the Toddler Gut Microbiome.

This study examines how feeding, sleep, and growth during infancy impact the gut microbiome (GM) in toddlers. The research was conducted on toddlers (n = 36), born to Latina women of low-income with obesity. Their mothers completed retrospective feeding and sleeping questionnaires at 1, 6, and 12 months; at 36 months, fecal samples were collected. Sequencing of the 16S rRNA gene (V4 region) revealed that breastfeeding for at least 1 month and the introduction of solids before 6 months differentiated the GM in toddlerhood (Bray-Curtis, pseudo-F = 1.805, p = 0.018, and pseudo-F = 1.651, p = 0.044, respectively). Sleep had an effect across time; at 1 and 6 months of age, a lower proportion of nighttime sleep (relative to 24 h total sleep) was associated with a richer GM at three years of age (Shannon H = 4.395, p = 0.036 and OTU H = 5.559, p = 0.018, respectively). Toddlers experiencing rapid weight gain from birth to 6 months had lower phylogenetic diversity (Faith PD H = 3.633, p = 0.057). These findings suggest that early life nutrition, sleeping patterns, and growth rate in infancy may influence the GM composition. Further verification of these results with objective sleep data and a larger sample is needed.

Gut microbiome remodeling and metabolomic profile improves in response to protein pacing with intermittent fasting versus continuous caloric restriction.

The gut microbiome (GM) modulates body weight/composition and gastrointestinal functioning; therefore, approaches targeting resident gut microbes have attracted considerable interest. Intermittent fasting (IF) and protein pacing (P) regimens are effective in facilitating weight loss (WL) and enhancing body composition. However, the interrelationships between IF- and P-induced WL and the GM are unknown. The current randomized controlled study describes distinct fecal microbial and plasma metabolomic signatures between combined IF-P (n = 21) versus a heart-healthy, calorie-restricted (CR, n = 20) diet matched for overall energy intake in free-living human participants (women = 27; men = 14) with overweight/obesity for 8 weeks. Gut symptomatology improves and abundance of Christensenellaceae microbes and circulating cytokines and amino acid metabolites favoring fat oxidation increase with IF-P (p < 0.05), whereas metabolites associated with a longevity-related metabolic pathway increase with CR (p < 0.05). Differences indicate GM and metabolomic factors play a role in WL maintenance and body composition. This novel work provides insight into the GM and metabolomic profile of participants following an IF-P or CR diet and highlights important differences in microbial assembly associated with WL and body composition responsiveness. These data may inform future GM-focused precision nutrition recommendations using larger sample sizes of longer duration. Trial registration, March 6, 2020 (ClinicalTrials.gov as NCT04327141), based on a previous randomized intervention trial.

Galacto-oligosaccharides increase calcium absorption and gut bifidobacteria in young girls: a double-blind cross-over trial.

Adolescence is a time for rapid growth that represents an opportunity to influence peak bone mass. Prebiotic agents, such as galacto-oligosaccharides (GOS), increase Ca absorption in animal models and postmenopausal women. The objectives of the present study were to investigate the dose-response relationship of GOS supplementation on Ca absorption during growth and to assess changes in colonic microbiota to better understand the mechanism by which GOS is acting. A total of thirty-one healthy adolescent girls aged 10-13 years consumed smoothie drinks twice daily with 0, 2·5 or 5 g GOS for three 3-week periods in a random order. Fractional Ca absorption was determined from urinary Ca excretion over 48 h at the end of each 3-week period using a dual stable isotope method. Faecal microbiota and bifidobacteria were assessed by PCR-denaturing gradient gel electrophoresis and quantitative PCR. Fractional Ca absorption after the 48 h treatment with control, 5 and 10 g GOS/d was 0·393 (SD 0·092), 0·444 (SD 0·086) and 0·419 (SD 0·099), respectively. Significant improvements in Ca absorption were seen with both low and high doses of GOS compared with the control (P,0·02), but itwas not a dose-response relationship. The increase in absorption was greatest in the urine collected after 24 h, which is consistent with lower gut absorption. Faecal bifidobacteria increased (control 10·89 (SD 13·86), 5 g GOS 22·80 (SD 15·74) and 10 g GOS 11·54 (SD 14·20)) with the GOS treatment (P,0·03). The results suggest that daily consumption of 5 g GOS increases Ca absorption, which may be mediated by the gut microbiota, specifically bifidobacteria.

Gut microbiome diversity, variability, and latent community types compared with shifts in body weight during the freshman year of college in dormitory-housed adolescents.

Significant human gut microbiome changes during adolescence suggest that microbial community evolution occurs throughout important developmental periods including the transition to college, a typical life phase of weight gain. In this observational longitudinal study of 139 college freshmen living in on-campus dormitories, we tracked changes in the gut microbiome via 16S amplicon sequencing and body weight across a single academic year. Participants were grouped by weight change categories of gain (WG), loss (WL), and maintenance (WM). Upon assessment of the community structure, unweighted and weighted UniFrac metrics revealed significant shifts with substantial variation explained by individual effects within weight change categories. Genera that positively contributed to these associations with weight change included Bacteroides, Blautia, and Bifidobacterium in WG participants and Prevotella and Faecalibacterium in WL and WM participants. Moreover, the Prevotella/Bacteroides ratio was significantly different by weight change category, with WL participants displaying an increased ratio. Importantly, these genera did not display co-dominance nor ease of transition between Prevotella- and Bacteroides-dominated states. We further assessed the overall taxonomic variation, noting the increased stability of the WL compared to the WG microbiome. Finally, we found 30 latent community structures within the microbiome with significant associations with waist circumference, sleep, and dietary factors, with alcohol consumption chief among them. Our findings highlight the high level of individual variation and the importance of initial gut microbiome community structure in college students during a period of major lifestyle changes. Further work is needed to confirm these findings and explore mechanistic relationships between gut microbes and weight change in free-living individuals.

The freshman year of college is a transitional period that may provide insights into the relationship between the gut microbiome and body weight regulation due to the lifestyle changes that increase vulnerability to weight change. During this critical period many of the lifestyle factors that influence body weight formalize and have important bearing on health outcomes throughout an individual's life. In this college-aged population, shifts in community structure and variability of gut microbes were different by weight change trajectory. Genera that underpinned these shifts such as Bacteroides, Blautia, Bifidobacterium, Prevotella, and Faecalibacterium displayed varying degrees of inter-individual variability and, in some instances, resistance to alternative states. Accounting for these considerations in the context of body weight control in adolescents may prove useful for improving target outcomes in an intervention setting.

Integrated multiomic wastewater-based epidemiology can elucidate population-level dietary behaviour and inform public health nutrition assessments.

Population-level nutritional assessments often rely on self-reported data, which increases the risk of recall bias. Here, we demonstrate that wastewater-based epidemiology can be used for near real-time population dietary assessments. Neighbourhood-level, untreated wastewater samples were collected monthly from within an urban population in the south-western United States from August 2017 to July 2019. Using liquid chromatography-tandem mass spectrometry, we identify recurring seasonal dynamics in phytoestrogen consumption, including dietary changes linked to the winter holiday season. Using 16S ribosomal RNA gene amplicon sequencing, we demonstrated the feasibility of detecting sewage-derived human gut bacterial taxa involved in phytoestrogen metabolism, including Bifidobacterium, Blautia and Romboutsia. Combined metabolomic and genomic wastewater analysis can inform nutritional assessments at population scale, indicating wastewater-based epidemiology as a promising tool for actionable and cost-effective data collection to support public health nutrition.