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Effects of Wholegrain Compared to Refined Grain Intake on Cardiometabolic Risk Markers, Gut Microbiota, and Gastrointestinal Symptoms in Children: A Randomized Crossover Trial.
Madsen, MTB, Landberg, R, Nielsen, DS, Zhang, Y, Anneberg, OMR, Lauritzen, L, Damsgaard, CT
The American journal of clinical nutrition. 2024;119(1):18-28
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High consumption of wholegrain foods has been linked to a lower risk of cardiovascular disease (CVD) and type 2 diabetes. Some trials have shown benefits to body weight, blood lipids and glucose homeostasis but most of these studies are with adults. Cardiometabolic disease begins in childhood therefore data is needed for this age group to back up dietary recommendations in order to prevent later development of cardiometabolic disease. The aim of this randomized crossover trial was to look at the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL), cholesterol and plasma insulin, other cardiometabolic markers, body composition, the composition of the gut microbiome and gastrointestinal symptoms in children with high body mass index (BMI). 55 healthy Danish children (aged 8 – 13) took part. They ate wholegrain oats and rye (WG) or refined grain products (RG) ad libtum for 8 weeks in random order. Measurements were taken at 0, 8 and 16 weeks. Compared with RG, WG reduced LDL cholesterol as well as total:high-density lipoprotein cholesterol and triacylglycerol. WG also modulated the abundance of specific types of gut bacteria, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. This study supports the recommendation to swap refined grain for wholegrain oats and rye in children. Further studies are needed.
Abstract
BACKGROUND Wholegrain intake is associated with lower risk of cardiometabolic diseases in adults, potentially via changes in the gut microbiota. Although cardiometabolic prevention should start early, we lack evidence on the effects in children. OBJECTIVES This study investigated the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL) cholesterol and plasma insulin (coprimary outcomes), other cardiometabolic markers, body composition, gut microbiota composition and metabolites, and gastrointestinal symptoms in children with high body mass index (BMI). METHODS In a randomized crossover trial, 55 healthy Danish 8- to 13-y-olds received wholegrain oats and rye ("WG") or refined grain ("RG") products ad libitum for 8 wk in random order. At 0, 8, and 16 wk, we measured anthropometry, body composition by dual-energy absorptiometry, and blood pressure. Fasting blood and fecal samples were collected for analysis of blood lipids, glucose homeostasis markers, gut microbiota, and short-chain fatty acids. Gut symptoms and stool characteristics were determined by questionnaires. Diet was assessed by 4-d dietary records and compliance by plasma alkylresorcinols (ARs). RESULTS Fifty-two children (95%) with a BMI z-score of 1.5 ± 0.6 (mean ± standard deviation) completed the study. They consumed 108 ± 38 and 3 ± 2 g/d wholegrain in the WG and RG period, which was verified by a profound difference in ARs (P < 0.001). Compared with RG, WG reduced LDL cholesterol by 0.14 (95% confidence interval: -0.24, -0.04) mmol/L (P = 0.009) and reduced total:high-density lipoprotein cholesterol (P < 0.001) and triacylglycerol (P = 0.048) without altering body composition or other cardiometabolic markers. WG also modulated the abundance of specific bacterial taxa, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. CONCLUSION High intake of wholegrain oats and rye reduced LDL cholesterol and triacylglycerol, modulated bacterial taxa, and increased beneficial metabolites in children. This supports recommendations of exchanging refined grain with wholegrain oats and rye among children. This trial was registered at clinicaltrials.gov as NCT04430465.
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Almond Consumption for 8 Weeks Altered Host and Microbial Metabolism in Comparison to a Control Snack in Young Adults.
Dhillon, J, Newman, JW, Fiehn, O, Ortiz, RM
Journal of the American Nutrition Association. 2023;42(3):242-254
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The consumption of almonds can improve cardiometabolic (CM) health. This study explored the effects of consuming a snack of almonds vs. crackers for 8 weeks on changes in cardiometabolic, microbiome and metabolomics markers in young adults. 73 (41 women and 32 men) young adults took part in this 8-week randomized controlled, parallel-arm intervention study. Blood samples were taken at the beginning, at 4 weeks and then at 8 weeks. The results looked at alternations in many serum metabolites involved in metabolic pathways. They therefore provide a deeper understanding of host carbohydrate, lipid and tocopherol metabolism. The findings also show the interconnections between circulating metabolites and microbial metabolism. This provides further evidence for the impacts of dietary changes on host metabolism and associated changes in gut microbe metabolism.
Abstract
Almond consumption can improve cardiometabolic (CM) health. However, the mechanisms underlying those benefits are not well characterized. This study explored the effects of consuming a snack of almonds vs. crackers for 8 weeks on changes in metabolomic profiles in young adults (clinicaltrials.gov ID: NCT03084003). Participants (n = 73, age: 18-19 years, BMI: 18-41 kg/m2) were randomly assigned to consume either almonds (2 oz/d, n = 38) or an isocaloric control snack of graham crackers (325 kcal/d, n = 35) daily for 8 weeks. Blood samples were collected at baseline prior to and at 4 and 8 weeks after the intervention. Metabolite abundances in the serum were quantified by hydrophilic interaction chromatography quadrupole (Q) time-of-flight (TOF) mass spectrometry (MS/MS), gas chromatography (GC) TOF MS, CSH-ESI (electrospray) QTOF MS/MS, and targeted analyses for free PUFAs, total fatty acids, oxylipins and endocannabinoids. Linear mixed model analyses with baseline-adjustment were conducted, and those results were used for enrichment and network analyses. Microbial community pathway predictions from 16S rRNA sequencing of fecal samples was done using PICRUST2. Almond consumption enriched unsaturated triglycerides, unsaturated phosphatidylcholines, saturated and unsaturated lysophosphatidylcholines, tricarboxylic acids, and tocopherol clusters (p < 0.05). Targeted analyses reveal lower levels of omega-3 total fatty acids (TFAs) overall in the almond group compared to the cracker group (p < 0.05). Microbial amino acid biosynthesis, and amino sugar and nucleotide sugar metabolism pathways were also differentially enriched at the end of the intervention (p < 0.05). The study demonstrates the differential effects of almonds on host tocopherol, lipid, and TCA cycle metabolism with potential changes in microbial metabolism, which may interact with host metabolism to facilitate the CM benefits.
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Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders.
Wilder-Smith, CH, Materna, A, Olesen, SS
Nutrients. 2023;15(10)
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Functional gastrointestinal disorders (FGID) are the most common cause of recurring, chronic digestive upsets. Irritable bowel syndrome (IBS) and functional dyspepsia (FD), or persistent indigestion, are the most prevalent types of those disorders. Typical symptoms include pain or discomfort in the abdomen, changes in stool patterns or bloating and may also manifest in symptoms not directly relating to the digestive tract. It remains uncertain what the exact mechanisms of those disorders are. However, scientists identified various factors involved, including immune system activation, sensitisation of the nervous system, dysregulated permeability of the gut walls, and changes in the microbiota, their composition and metabolic activity. Polyphenols are natural compounds found abundantly in plants and are most known for their antioxidant qualities. One frequently studied and rich-source of phenols is Blueberries (Vaccinium spp). Blueberries have antioxidant, anti-inflammatory, and neuroprotective properties, and are known to reverse the permeability of the gut membrane. Hence their use in the management of FGID appeared promising. This double-blind, randomized, cross-over study assessed the benefit of blueberries in 43 people with IBS or FD, between 18–60 years of age. The candidates were given 30g freeze-dried blueberries, the equivalent of 180g of fresh blueberries, or a sugar-based placebo of similar calorific value for 6-weeks each. When receiving the blueberries, greater symptom relief was observed when compared to the placebo group. Blueberry intake also positively reflected in experienced improvement in quality of life. No notable differences were observed between groups in stool patterns and fructose digestion. Blueberries and their beneficial compounds such as polyphenols and fiber appear to have a wide range of benefits that can help manage some of the FGID-associated symptoms. Further studies are needed to understand why, despite some notable benefits, some of the other GI markers remained unaffected. As blueberries are generally well tolerated, they can be a simple and helpful food intervention to complement other FGID management strategies.
Abstract
Blueberries beneficially modulate physiologic mechanisms relevant to the pathogenesis of functional gastrointestinal disorders (FGID). Forty-three patients with FGID received freeze-dried blueberries (equivalent to 180 g fresh blueberries) or sugar and energy-matched placebo in a double-blind, randomized, cross-over study. After 6 weeks of treatment, the differences in Gastrointestinal Clinical Rating Scale (GSRS) scores and abdominal symptom relief were compared as primary outcome measures. The quality of life and life functioning ratings (OQ45.2 questionnaire), Bristol stool scales, and fructose breath test results constituted secondary outcome measures. Blueberry treatment resulted in more patients with relevant abdominal symptom relief compared to placebo (53% vs. 30%, p = 0.03). Total and pain GSRS scores improved insignificantly (mean treatment differences [95% CI]: -3.4 [-7.4 to 0.6] (p = 0.09) and -1.0 [-2.2 to 0.1] (p = 0.08), respectively). OQ45.2 scores improved during blueberry treatment compared to placebo (treatment difference -3.2 [95% CI: -5.6 to -0], p = 0.01). Treatment effect differences for the further measures did not reach statistical significance. Blueberries relieved abdominal symptoms and improved general markers of well-being, quality of life, and life functioning more than placebo in patients with FGID. Consequently, the polyphenol and fiber components of blueberries exert broad beneficial effects separate from the sugars present in both treatments.
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Effect of a Hop Extract Standardized in 8-Prenylnaringenin on Bone Health and Gut Microbiome in Postmenopausal Women with Osteopenia: A One-Year Randomized, Double-Blind, Placebo-Controlled Trial.
Lecomte, M, Tomassi, D, Rizzoli, R, Tenon, M, Berton, T, Harney, S, Fança-Berthon, P
Nutrients. 2023;15(12)
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Osteoporosis is a bone condition characterized by weakened and brittle bones, leading to an increased risk of fractures. Oestrogens play a vital role in maintaining bone health, whereby oestrogen deficiency elevates the risk of osteoporosis and fractures, particularly in menopausal women due to the decline in oestrogen levels. Phytoestrogens, plant-derived compounds capable of interacting with human oestrogen receptors, have presented an intriguing non-pharmaceutical avenue for preventing bone loss. Other phytoestrogens have received some attention in the field, however, limited human research exists on prenylflavonoids, a phytoestrogens found in hops (Humulus lupulus). This randomized, double-blinded, placebo-controlled trial aimed to investigate the effects of a year-long supplementation of standardised hop extract (8-PN) Lifenol® on bone mineral density in postmenopausal women. Additionally, the study explored potential mechanisms, particularly focusing on changes in gut bacteria. Notably, gut bacteria play a role in bone metabolism and the pathogenesis of osteoporosis. They are also, along with the liver, responsible for converting hops phenols into active phytoestrogenic compounds. The trial was completed by 95 postmenopausal, women with Osteopenia aged 50 to 85. They all received calcium and vitamin D3 tablets in addition either a hop extract (100mcg) or a placebo for 48 weeks. Changes were monitored using DXA scans for bone mineral density (BMD) and bone metabolism, blood samples for markers for bone health, a quality of life questionnaire, gut microbiome testing, and tests for short-chain fatty acid (SCFA) levels. In conclusion, the intake of hop extract confirmed a previously observed trend of a slight increase in total bone mineral density (BMD), in addition to the benefits linked to calcium and vitamin D supplementation. Although there were no significant changes in the composition of gut bacteria and SCFA levels, the hop extract candidates had a higher abundance of specific genera associated with total body BMD, suggesting a potential positive impact. Larger studies are required to validate these findings.
Abstract
Estrogen deficiency increases the risk of osteoporosis and fracture. The aim of this study was to investigate whether a hop extract standardized in 8-prenylnaringenin (8-PN), a potent phytoestrogen, could improve bone status of osteopenic women and to explore the gut microbiome roles in this effect. In this double-blind, placebo-controlled, randomized trial, 100 postmenopausal, osteopenic women were supplemented with calcium and vitamin D3 (CaD) tablets and either a hop extract (HE) standardized in 8-PN (n = 50) or a placebo (n = 50) for 48 weeks. Bone mineral density (BMD) and bone metabolism were assessed by DXA measurements and plasma bone biomarkers, respectively. Participant's quality of life (SF-36), gut microbiome composition, and short-chain fatty acid (SCFA) levels were also investigated. In addition to the CaD supplements, 48 weeks of HE supplementation increased total body BMD (1.8 ± 0.4% vs. baseline, p < 0.0001; 1.0 ± 0.6% vs. placebo, p = 0.08), with a higher proportion of women experiencing an increase ≥1% compared to placebo (odds ratio: 2.41 ± 1.07, p < 0.05). An increase in the SF-36 physical functioning score was observed with HE versus placebo (p = 0.05). Gut microbiome α-diversity and SCFA levels did not differ between groups. However, a higher abundance of genera Turicibacter and Shigella was observed in the HE group; both genera have been previously identified as associated with total body BMD. These results suggest that an 8-PN standardized hop extract could beneficially impact bone health of postmenopausal women with osteopenia.
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Functional response to a microbial synbiotic in the gastrointestinal system of children: a randomized clinical trial.
Tierney, BT, Versalovic, J, Fasano, A, Petrosino, JF, Chumpitazi, BP, Mayer, EA, Boetes, J, Smits, G, Parkar, SG, Voreades, N, et al
Pediatric research. 2023;93(7):2005-2013
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The composition of the human gut microbiome has been identified as playing a role in regulating bowel movements in children. This includes functional constipation, which is characterised by infrequent bowel movements and associated phenotypes such as stool consistency, pain when defecating and bloating. The aim of this study was to determine the impact of a nine-strain (eight species) synbiotic (a prebiotic and defined microbial consortium) formulation (with the prebiotic comprising mixed-chain length oligosaccharides) on ameliorating constipation. This study was a multicentre, randomised, double-blind, and placebo-controlled with two parallel arms. Ninety-one healthy male/female subjects were recruited and randomly assigned to one of the two arms; treatment or placebo group. Results showed that: - compared to placebo, synbiotic use increased weekly bowel movements (WBMs) in constipated children. - there was an increased abundance of the administered probiotic species (bifidobacteria) in the treatment arm. - baseline microbial richness demonstrated potential as a predictive biomarker for response to intervention. Authors conclude that a synbiotic formulation may increase weekly WBMs in children who have low-frequency WBMs.
Abstract
BACKGROUND Oral microbial therapy has been studied as an intervention for a range of gastrointestinal disorders. Though research suggests that microbial exposure may affect the gastrointestinal system, motility, and host immunity in a pediatric population, data have been inconsistent, with most prior studies being in neither a randomized nor placebo-controlled setting. The aim of this randomized, placebo-controlled study was to evaluate the efficacy of a synbiotic on increasing weekly bowel movements (WBMs) in constipated children. METHODS Sixty-four children (3-17 years of age) were randomized to receive a synbiotic (n = 33) comprising mixed-chain length oligosaccharides and nine microbial strains, or placebo (n = 31) for 84 days. Stool microbiota was analyzed on samples collected at baseline and completion. The primary outcome was a change from baseline of WBMs in the treatment group compared to placebo. RESULTS Treatment increased (p < 0.05) the number of WBMs in children with low baseline WBMs, despite broadly distinctive baseline microbiome signatures. Sequencing revealed that low baseline microbial richness in the treatment group significantly anticipated improvements in constipation (p = 0.00074). CONCLUSIONS These findings suggest the potential for (i) multi-species-synbiotic interventions to improve digestive health in a pediatric population and (ii) bioinformatics-based methods to predict response to microbial interventions in children. IMPACT Synbiotic microbial treatment improved the number of spontaneous weekly bowel movements in children compared to placebo. Intervention induced an increased abundance of bifidobacteria in children, compared to placebo. All administered probiotic species were enriched in the gut microbiome of the intervention group compared to placebo. Baseline microbial richness demonstrated potential as a predictive biomarker for response to intervention.
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Effects of Gut Microbiome Modulation on Reducing Adverse Health Outcomes among Elderly and Diabetes Patients during the COVID-19 Pandemic: A Randomised, Double-Blind, Placebo-Controlled Trial (IMPACT Study).
Wong, MCS, Zhang, L, Ching, JYL, Mak, JWY, Huang, J, Wang, S, Mok, CKP, Wong, A, Chiu, OL, Fung, YT, et al
Nutrients. 2023;15(8)
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Worldwide, the coronavirus disease 2019 (COVID-19) pandemic has posed a substantial challenge in terms of its induced morbidity and mortality to the general population. Patients with diabetes and elderly individuals are particularly vulnerable during the pandemic. The aim of this study was to assess the efficacy of a novel microbiome immunity formula (SIM01) in reducing adverse health outcomes in the elderly and patients with type two diabetes mellitus during the COVID-19 pandemic. This study was a double-blind, randomised, parallel-arm, placebo-controlled trial. Participants were randomly assigned to receive a microbiome immunity formula (SIM01) or placebo in a 1:1 ratio for three months. Results showed that SIM01, could reduce adverse health outcomes, improve quality of life, and restore gut dysbiosis among elderly subjects and patients with type two diabetes during the COVID-19 pandemic. In fact, SIM01 not only replenished Bifidobacteria but also favoured the coexistence of other beneficial species. Authors conclude that their findings provide significant societal implications for strategies that could protect these vulnerable individuals during the COVID-19 pandemic.
Abstract
Gut microbiota is believed to be a major determinant of health outcomes. We hypothesised that a novel oral microbiome formula (SIM01) can reduce the risk of adverse health outcomes in at-risk subjects during the coronavirus disease 2019 (COVID-19) pandemic. In this single-centre, double-blind, randomised, placebo-controlled trial, we recruited subjects aged ≥65 years or with type two diabetes mellitus. Eligible subjects were randomised in a 1:1 ratio to receive three months of SIM01 or placebo (vitamin C) within one week of the first COVID-19 vaccine dose. Both the researchers and participants were blinded to the groups allocated. The rate of adverse health outcomes was significantly lower in the SIM01 group than the placebo at one month (6 [2.9%] vs. 25 [12.6], p < 0.001) and three months (0 vs. 5 [3.1%], p = 0.025). At three months, more subjects who received SIM01 than the placebo reported better sleep quality (53 [41.4%] vs. 22 [19.3%], p < 0.001), improved skin condition (18 [14.1%] vs. 8 [7.0%], p = 0.043), and better mood (27 [21.2%] vs. 13 [11.4%], p = 0.043). Subjects who received SIM01 showed a significant increase in beneficial Bifidobacteria and butyrate-producing bacteria in faecal samples and strengthened the microbial ecology network. SIM01 reduced adverse health outcomes and restored gut dysbiosis in elderly and diabetes patients during the COVID-19 pandemic.
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Effect of an Exclusive Human Milk Diet on the Gut Microbiome in Preterm Infants: A Randomized Clinical Trial.
Embleton, ND, Sproat, T, Uthaya, S, Young, GR, Garg, S, Vasu, V, Masi, AC, Beck, L, Modi, N, Stewart, CJ, et al
JAMA network open. 2023;6(3):e231165
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Receipt of mother’s own breast milk (MOM) is associated with lower rates of neonatal morbidities in preterm infants and improved long-term metabolic and neurocognitive outcomes. However, many experience a shortfall in MOM supply necessitating the use of either bovine formula or pasteurised human milk. The hypothesis of this study was that gut bacterial diversity and proportions of specific bacterial taxa would differ between trial groups as part of the mechanism by which exclusive human milk diets benefits preterm infants. This study was a randomised clinical trial for which preterm infants in the first 72 hours of life (born less than 30 weeks of gestation) were recruited. Infants (n=126) were randomly assigned to standard (control) or exclusive human milk diet (intervention). Results showed that the intervention group had no overall effect on gut microbiome richness or Shannon diversity. Furthermore, Bifidobacterium relative abundance was not associated with an exclusive human milk diet. Authors conclude that their findings show that pasteurized human milk (or products derived from human milk) do not exert a major impact on gut bacteria when used in addition to MOM.
Abstract
IMPORTANCE The effect of using an exclusive human milk diet compared with one that uses bovine products in preterm infants is uncertain, but some studies demonstrate lower rates of key neonatal morbidities. A potential mediating pathway is the gut microbiome. OBJECTIVE To determine the effect of an exclusive human milk diet on gut bacterial richness, diversity, and proportions of specific taxa in preterm infants from enrollment to 34 weeks' postmenstrual age. DESIGN, SETTING, AND PARTICIPANTS In this randomized clinical trial conducted at 4 neonatal intensive care units in the United Kingdom from 2017 to 2020, microbiome analyses were blind to group. Infants less than 30 weeks' gestation who had only received own mother's milk were recruited before 72 hours of age. Statistical analysis was performed from July 2019 to September 2021. INTERVENTIONS Exclusive human milk diet using pasteurized human milk for any shortfall in mother's own milk supply and human milk-derived fortifiers (intervention) compared with bovine formula and bovine-derived fortifier (control) until 34 weeks' postmenstrual age. Fortifier commenced less than 48 hours of tolerating 150 mL/kg per day. MAIN OUTCOMES AND MEASURES Gut microbiome profile including alpha and beta diversity, and presence of specific bacterial taxa. RESULTS Of 126 preterm infants enrolled in the study, 63 were randomized to control (median [IQR] gestation: 27.0 weeks [26.0-28.1 weeks]; median [IQR] birthweight: 910 g [704-1054 g]; 32 [51%] male) and 63 were randomized to intervention (median [IQR] gestation: 27.1 weeks [25.7-28.1 weeks]; median [IQR] birthweight: 930 g [733-1095 g]; 38 [60%] male); 472 stool samples from 116 infants were analyzed. There were no differences in bacterial richness or Shannon diversity over time, or at 34 weeks between trial groups. The exclusive human milk diet group had reduced relative abundance of Lactobacillus after adjustment for confounders (coefficient estimate, 0.056; P = .03), but not after false discovery rate adjustment. There were no differences in time to full feeds, necrotizing enterocolitis, or other key neonatal morbidities. CONCLUSIONS AND RELEVANCE In this randomized clinical trial in preterm infants using human milk-derived formula and/or fortifier to enable an exclusive human milk diet, there were no effects on overall measures of gut bacterial diversity but there were effects on specific bacterial taxa previously associated with human milk receipt. These findings suggest that the clinical impact of human milk-derived products is not modulated via microbiomic mechanisms. TRIAL REGISTRATION ISRCTN trial registry identifier: ISRCTN16799022.
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The effect of vitamin D supplementation on the gut microbiome in older Australians - Results from analyses of the D-Health Trial.
Pham, H, Waterhouse, M, Rahman, S, Baxter, C, Duarte Romero, B, McLeod, DSA, Ebeling, PR, English, DR, Hartel, G, O'Connell, RL, et al
Gut microbes. 2023;15(1):2221429
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Microbiota are communities of microorganisms that co-exist with the host ecosystem in a specific environment. The term microbiome refers to the microbial genome. The aim of this study was to investigate the effect of supplementing older adults with 60,000 IU of vitamin D per month on the gut microbiome for a period of five years, using a subsample (n = 835) of participants recruited from the large population-based D-Health Trial. This study is based on a subsample from the D-Health Trial, which was a randomised, double-blind trial with two parallel arms. Participants were randomly allocated (1:1 ratio) to monthly doses of either 60,000 IU of cholecalciferol (vitamin D3) or matching placebo. Results showed that monthly doses of 60,000 IU vitamin D over 5 years did not alter the composition of the gut microbiome in a population that is largely vitamin D replete. Authors conclude that further investigation is required to examine whether non-bolus doses of vitamin D would influence the gut microbiome or whether vitamin D supplementation would be beneficial in populations with a higher prevalence of vitamin D deficiency.
Abstract
Observational studies suggest a link between vitamin D and the composition of the gut microbiome, but there is little evidence from randomized controlled trials of vitamin D supplementation. We analyzed data from the D-Health Trial, a randomized, double-blind, placebo-controlled trial. We recruited 21,315 Australians aged 60-84 y and randomized them to 60,000 IU of vitamin D3 or placebo monthly for 5 y. Stool samples were collected from a sample of 835 participants (417 in the placebo and 418 in the vitamin D group) approximately 5 y after randomization. We characterized the gut microbiome using 16S rRNA gene sequencing. We used linear regression to compare alpha diversity indices (i.e. Shannon index (primary outcome), richness, inverse Simpson index), and the ratio of Firmicutes to Bacteroidetes between the two groups. We analyzed between-sample (beta) diversity (i.e. Bray Curtis distance and UniFrac index) using principal coordinate analysis and used PERMANOVA to test for significant clustering according to randomization group. We also assessed the difference in the abundance of the 20 most abundant genera between the two groups using negative binomial regression model with adjustment for multiple testing. Approximately half the participants included in this analysis were women (mean age 69.4 y). Vitamin D supplementation did not alter the Shannon diversity index (mean 3.51 versus 3.52 in the placebo and vitamin D groups, respectively, p = 0.50). Similarly, there was little difference between the groups for other alpha diversity indices, the abundance of different genera, and the Firmicutes-to-Bacteroidetes ratio. We did not observe clustering of bacterial communities according to randomization group. In conlusion, monthly doses of 60,000 IU of vitamin D supplementation for 5 y did not alter the composition of the gut microbiome in older Australians.
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A Mediterranean Diet Pattern Improves Intestinal Inflammation Concomitant with Reshaping of the Bacteriome in Ulcerative Colitis: A Randomised Controlled Trial.
Haskey, N, Estaki, M, Ye, J, Shim, RK, Singh, S, Dieleman, LA, Jacobson, K, Gibson, DL
Journal of Crohn's & colitis. 2023;17(10):1569-1578
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Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) with debilitating symptoms. Patients live with considerable symptom burden, increased risk of disability, and lower quality of life despite medical treatment. The aim of this study was to investigate the efficacy of the Mediterranean Diet Pattern (MDP) compared with a Canadian Habitual Diet Pattern (CHD) on UC disease activity, inflammation, and the gut microbiome. This study was a randomised controlled trial where participants were randomly assigned to follow the MDP or CHD for 12 weeks. Results showed that: - the MDP reduces clinical symptoms and reduces inflammation. - the MDP promotes faecal secretory immunoglobulin A [the principal weapon protecting us from pathogens and toxins that might otherwise penetrate mucosal surfaces. - the MDP is positively associated with microbes that produce potentially beneficial metabolites. - the MDP is negatively associated with microbes predicted to carry pathobiont traits. - the MDP increases faecal short-chain fatty acids production. Authors conclude that the MDP is well tolerated and is a reasonable, healthy eating pattern that practitioners can recommend to patients with UC in remission to prevent relapses, in addition to their standard medical therapy.
Abstract
BACKGROUND AND AIMS Dietary patterns are important in managing ulcerative colitis [UC], given their influence on gut microbiome-host symbiosis and inflammation. We investigated whether the Mediterranean Diet Pattern [MDP] vs the Canadian Habitual Diet Pattern [CHD] would affect disease activity, inflammation, and the gut microbiome in patients with quiescent UC. METHODS We performed a prospective, randomised, controlled trial in adults [65% female; median age 47 years] with quiescent UC in an outpatient setting from 2017 to 2021. Participants were randomised to an MDP [n = 15] or CHD [n = 13] for 12 weeks. Disease activity [Simple Clinical Colitis Activity Index] and faecal calprotectin [FC] were measured at baseline and week 12. Stool samples were analysed by 16S rRNA gene amplicon sequencing. RESULTS The diet was well tolerated by the MDP group. At week 12, 75% [9/12] of participants in the CHD had an FC >100 μg/g, vs 20% [3/15] of participants in the MDP group. The MDP group had higher levels of total faecal short chain fatty acids [SCFAs] [p = 0.01], acetic acid [p = 0.03], and butyric acid [p = 0.03] compared with the CHD. Furthermore, the MDP induced alterations in microbial species associated with a protective role in colitis [Alistipes finegoldii and Flavonifractor plautii], as well as the production of SCFAs [Ruminococcus bromii]. CONCLUSIONS An MDP induces gut microbiome alterations associated with the maintenance of clinical remission and reduced FC in patients with quiescent UC. The data support that the MDP is a sustainable diet pattern that could be recommended as a maintenance diet and adjunctive therapy for UC patients in clinical remission. ClinicalTrials.gov no: NCT0305371.
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The Effect of Oral Iron Supplementation on Gut Microbial Composition: a Secondary Analysis of a Double-Blind, Randomized Controlled Trial among Cambodian Women of Reproductive Age.
Finlayson-Trick, E, Nearing, J, Fischer, JA, Ma, Y, Wang, S, Krouen, H, Goldfarb, DM, Karakochuk, CD
Microbiology spectrum. 2023;11(3):e0527322
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Iron supplementation is recommended for all women of reproductive age in Cambodia, where anaemia has a high prevalence. The gut microbiome contains iron-dependent bacteria with the potential to cause intestinal disease (enteropathogens). The aim of this study was to examine changes in the gut microbiome following 12 weeks of daily supplementation of either ferrous sulfate or ferrous bisglycinate in non-pregnant Cambodian women of reproductive age. This study was nested within a larger randomised controlled trial of oral iron supplementation that included 480 non-pregnant Cambodian women. The participants were randomised at a 1:1:1 allocation ratio to either ferrous sulfate, ferrous bisglycinate, or placebo. Results showed that daily iron supplementation did not significantly affect gut bacterial diversity. However, iron supplementation, in the form of ferrous bisglycinate, increases the relative abundance of Enterobacteriaceae. Authors conclude that their findings can facilitate future research that may inform evidence-based global practice and policy.
Abstract
The World Health Organization recommends untargeted iron supplementation for women of reproductive age (WRA) in countries where anemia prevalence is greater than 40%, such as Cambodia. Iron supplements, however, often have poor bioavailability, so the majority remains unabsorbed in the colon. The gut houses many iron-dependent bacterial enteropathogens; thus, providing iron to individuals may be more harmful than helpful. We examined the effects of two oral iron supplements with differing bioavailability on the gut microbiomes in Cambodian WRA. This study is a secondary analysis of a double-blind, randomized controlled trial of oral iron supplementation in Cambodian WRA. For 12 weeks, participants received ferrous sulfate, ferrous bisglycinate, or placebo. Participants provided stool samples at baseline and 12 weeks. A subset of stool samples (n = 172), representing the three groups, were randomly selected for gut microbial analysis by 16S rRNA gene sequencing and targeted real-time PCR (qPCR). At baseline, 1% of women had iron-deficiency anemia. The most abundant gut phyla were Bacteroidota (45.7%) and Firmicutes (42.1%). Iron supplementation did not alter gut microbial diversity. Ferrous bisglycinate increased the relative abundance of Enterobacteriaceae, and there was a trend towards an increase in the relative abundance of Escherichia-Shigella. qPCR detected an increase in the enteropathogenic Escherichia coli (EPEC) virulence gene, bfpA, in the group that received ferrous sulfate. Thus, iron supplementation did not affect overall gut bacterial diversity in predominantly iron-replete Cambodian WRA, however, evidence does suggest an increase in relative abundance within the broad family Enterobacteriaceae associated with ferrous bisglycinate use. IMPORTANCE To the best of our knowledge, this is the first published study to characterize the effects of oral iron supplementation on the gut microbiomes of Cambodian WRA. Our study found that iron supplementation with ferrous bisglycinate increases the relative abundance of Enterobacteriaceae, which is a family of bacteria that includes many Gram-negative enteric pathogens like Salmonella, Shigella, and Escherichia coli. Using qPCR for additional analysis, we were able to detect genes associated with enteropathogenic E. coli, a type of diarrheagenic E. coli known to be present around the world, including water systems in Cambodia. The current WHO guidelines recommend blanket (untargeted) iron supplementation for Cambodian WRA despite a lack of studies in this population examining iron's effect on the gut microbiome. This study can facilitate future research that may inform evidence-based global practice and policy.