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Collinsella aerofaciens as a predictive marker of response to probiotic treatment in non-constipated irritable bowel syndrome.
Gargari, G, Mantegazza, G, Cremon, C, Taverniti, V, Valenza, A, Barbaro, MR, Marasco, G, Duncan, R, Fiore, W, Ferrari, R, et al
Gut microbes. 2024;16(1):2298246
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Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction in which recurrent abdominal pain is associated with defecation or a change in bowel habits. Various therapeutic options for IBS target the underlying pathophysiological aspects of the condition. Unfortunately, no single approach can effectively address this disorder’s diverse manifestations simultaneously. The aim of this study was to identify markers for recognising non-constipated (NC) IBS patients that may show significant clinical improvements upon treatment with the probiotic strain Lacticaseibacillus paracasei DG (LDG). This study is based on a multicentre, randomised, double-blind, parallel-group, placebo-controlled clinical trial. A total of 63 patients were included in this study who were randomised to receive a probiotic treatment or placebo capsules for 12 weeks. Results showed that the probiotic bacterium LDG can be clinically effective in a subgroup of non-constipated IBS patients characterised by an altered faecal microbiota which resembles that observed in metabolic syndrome-associated pathologic or pre-pathologic conditions. Furthermore, a bacterium reported to contribute to pro-inflammatory immune states, was positively associated with markers of increased endothelial permeability and liver functionality Authors concluded that an analysis of the faecal microbiota focused on particular bacteria could permit the identification of NC-IBS patients who can obtain a significant clinical benefit from the probiotic treatment.
Abstract
Probiotics are exploited for adjuvant treatment in IBS, but reliable guidance for selecting the appropriate probiotic to adopt for different forms of IBS is lacking. We aimed to identify markers for recognizing non-constipated (NC) IBS patients that may show significant clinical improvements upon treatment with the probiotic strain Lacticaseibacillus paracasei DG (LDG). To this purpose, we performed a post-hoc analysis of samples collected during a multicenter, double-blind, parallel-group, placebo-controlled trial in which NC-IBS patients were randomized to receive at least 24 billion CFU LDG or placebo capsules b.i.d. for 12 weeks. The primary clinical endpoint was the composite response based on improved abdominal pain and fecal type. The fecal microbiome and serum markers of intestinal (PV1 and zonulin), liver, and kidney functions were investigated. We found that responders (R) in the probiotic arm (25%) differed from non-responders (NR) based on the abundance of 18 bacterial taxa, including the families Coriobacteriaceae, Dorea spp. and Collinsella aerofaciens, which were overrepresented in R patients. These taxa also distinguished R (but not NR) patients from healthy controls. Probiotic intervention significantly reduced the abundance of these bacteria in R, but not in NR. Analogous results emerged for C. aerofaciens from the analysis of data from a previous trial on IBS with the same probiotic. Finally, C. aerofaciens was positively correlated with the plasmalemmal vesicle associated protein-1 (PV-1) and the markers of liver function. In conclusion, LDG is effective on NC-IBS patients with NC-IBS with a greater abundance of potential pathobionts. Among these, C. aerofaciens has emerged as a potential predictor of probiotic efficacy.
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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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Randomized controlled trial demonstrates response to a probiotic intervention for metabolic syndrome that may correspond to diet.
Wastyk, HC, Perelman, D, Topf, M, Fragiadakis, GK, Robinson, JL, Sonnenburg, JL, Gardner, CD, Sonnenburg, ED
Gut microbes. 2023;15(1):2178794
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Rates of metabolic syndrome are high throughout developed countries. Metabolic syndrome is a cluster of conditions that occur together and increase your risk for heart disease, stroke, and type 2 diabetes. Studies in animals and humans have shown that the composition of the gut microbiome may be linked to metabolic syndrome and that it is affected by diet. This randomised control trial of 39 individuals showed that the supplementation of a probiotic containing three different probiotic strains did not have a population wide effect but did influence a subset of individuals. These individuals had a different microbiome by the end of the trial and a decrease in blood pressure and blood lipids. Interestingly these individuals also had a higher dietary intake of sugar, yet a lower blood sugar level. It was concluded that the response to probiotic supplements may be dependent upon an individual’s diet. This study could be used by healthcare professionals to understand that diet may influence the success of probiotics, however more research is warranted before firm conclusions are made on the optimal diet during supplementation.
Abstract
An individual's immune and metabolic status is coupled to their microbiome. Probiotics offer a promising, safe route to influence host health, possibly via the microbiome. Here, we report an 18-week, randomized prospective study that explores the effects of a probiotic vs. placebo supplement on 39 adults with elevated parameters of metabolic syndrome. We performed longitudinal sampling of stool and blood to profile the human microbiome and immune system. While we did not see changes in metabolic syndrome markers in response to the probiotic across the entire cohort, there were significant improvements in triglycerides and diastolic blood pressure in a subset of probiotic arm participants. Conversely, the non-responders had increased blood glucose and insulin levels over time. The responders had a distinct microbiome profile at the end of the intervention relative to the non-responders and placebo arm. Importantly, diet was a key differentiating factor between responders and non-responders. Our results show participant-specific effects of a probiotic supplement on improving parameters of metabolic syndrome and suggest that dietary factors may enhance stability and efficacy of the supplement.
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Effects of FODMAPs and Gluten on Gut Microbiota and Their Association with the Metabolome in Irritable Bowel Syndrome: A Double-Blind, Randomized, Cross-Over Intervention Study.
Nordin, E, Hellström, PM, Dicksved, J, Pelve, E, Landberg, R, Brunius, C
Nutrients. 2023;15(13)
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Irritable bowel syndrome (IBS) is defined as recurring abdominal pain in relation to stool irregularities. The mechanisms behind IBS are poorly understood, but changes in gut microbiota composition, intestinal barrier function, enteroendocrine cell population, low-grade inflammation and gut–brain axis modulations are believed to play a role. The aim of this study was to investigate how fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms. This study was a double-blind, placebo-controlled three-way crossover study. Both the study personnel and participants were blinded. Results showed that consumption of high FODMAP foods, but not gluten, altered the gut microbiota composition, in particular causing changes to microbiota and metabolites, previously associated with improved metabolic health and reduced inflammation. There were also minor effects of FODMAPs and gluten on short-chain fatty acids. Authors conclude that the intake of FODMAP, but not gluten, over one week altered the gut microbiota composition, with only weak associations with IBS symptoms. Healthcare practitioners working with IBS should consider the impacts on the gut microbiome when advising the use of a low-FODMAP diet.
Abstract
BACKGROUND A mechanistic understanding of the effects of dietary treatment in irritable bowel syndrome (IBS) is lacking. Our aim was therefore to investigate how fermentable oligo- di-, monosaccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms. METHODS We used data from a double-blind, randomized, crossover study with week-long provocations of FODMAPs, gluten, and placebo in participants with IBS. To study the effects of the provocations on fecal microbiota, fecal and plasma short-chain fatty acids, the untargeted plasma metabolome, and IBS symptoms, we used Random Forest, linear mixed model and Spearman correlation analysis. RESULTS FODMAPs increased fecal saccharolytic bacteria, plasma phenolic-derived metabolites, 3-indolepropionate, and decreased isobutyrate and bile acids. Gluten decreased fecal isovalerate and altered carnitine derivatives, CoA, and fatty acids in plasma. For FODMAPs, modest correlations were observed between microbiota and phenolic-derived metabolites and 3-indolepropionate, previously associated with improved metabolic health, and reduced inflammation. Correlations between molecular data and IBS symptoms were weak. CONCLUSIONS FODMAPs, but not gluten, altered microbiota composition and correlated with phenolic-derived metabolites and 3-indolepropionate, with only weak associations with IBS symptoms. Thus, the minor effect of FODMAPs on IBS symptoms must be weighed against the effect on microbiota and metabolites related to positive health factors.
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PRO-DEMET Randomized Controlled Trial on Probiotics in Depression-Pilot Study Results.
Gawlik-Kotelnicka, O, Margulska, A, Skowrońska, A, Strzelecki, D
Nutrients. 2023;15(6)
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Depression often coexists with metabolic abnormalities, and metabolic syndrome (MetS) is diagnosed in 30% of depressed subjects. Importantly, both obesity and MetS have been found to be independently associated with depressive symptoms and inflammation. The aim of this study was to investigate the effect of probiotics in the treatment of depressive disorders with possible comorbid MetS and its components. This study was an internal feasibility study based on the main randomised study - a single-centre, parallel-group, prospective, randomised, double-blind, placebo-controlled pilot trial. Adult patients (≥18 years) with depressive disorders were randomly assigned (1:1) into either the placebo or probiotic group. Results showed a positive association between probiotics supplementation and psychometric parameters together with the metabolic profile, serum inflammation markers, and biomarkers of metabolic-associated fatty liver disease in patients with depressive disorders. Authors conclude that the findings of their study would be suitable for determining the potential clinical use of probiotics and assessing certain key factors such as potential biomarkers of response.
Abstract
There is a pressing need to identify new treatment options for depression and its comorbidities. Depression often coexists with metabolic complications, and the two may share a pathophysiological overlap, including inflammation and microbiota changes. Microbiota interventions (e.g., probiotics) may represent a safe and easy-to-use treatment option as an adjunctive therapy in patients only partially responsive to pharmacologic treatment. (1) Objective: The paper presents the results of a feasibility and pilot study. The study is an internal part of a randomized controlled trail (RCT) of the effect of probiotic supplementation on psychometric, anthropometric, metabolic, and inflammatory parameters in adult patients with depressive disorders depending on the presence of metabolic syndrome. (2) Methods: The trial has a four-arm, parallel-group, prospective, randomized, double-blind, controlled design. Sixty participants received a probiotic preparation containing Lactobacillus helveticus Rosell®-52 and Bifidobacterium longum Rosell®-175 over 60 days. The feasibility of the study design was assessed, as well as the rates of recruitment, eligibility, consent, and study completion. The following were assessed: depressive, anxiety and stress symptoms, quality of life, blood pressure, body mass index and waist circumference, complete blood count with differential, serum levels of C-reactive protein, high-density lipoprotein cholesterol, triglycerides, fasting glucose, some secondary markers of inflammation and metabolic health, as well as noninvasive biomarkers of liver fibrosis (APRI and FIB-4). (3) Results: The study was found to be generally feasible. The eligibility rate was 52% of recruited participants with 80% completing the study protocol. No differences in sociodemographic or anthropometric factors or basic laboratory findings were found between the placebo and probiotic group at the start of the intervention period. Importantly, the proportion of recruited participants fulfilling the criteria of metabolic syndrome was too low. (4) Conclusions: Whilst the whole study protocol was feasible, some different timepoint procedures require modification. The major weakness of the recruitment methods was that the percentage of metabolic arms participants was insufficient. Overall, the full RCT design on probiotics in depression with vs. without metabolic syndrome was shown to be feasible with little modification.
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The Usefulness of the Low-FODMAP Diet with Limited Tryptophan Intake in the Treatment of Diarrhea-Predominant Irritable Bowel Syndrome.
Chojnacki, C, Poplawski, T, Blonska, A, Konrad, P, Chojnacki, J, Blasiak, J
Nutrients. 2023;15(8)
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Several pathogenic factors are responsible for the occurrence of irritable bowel syndrome (IBS-D), and food products are present among them. The human diet contains various nutrients, which may have beneficial or unfavourable effects. Numerous patients with IBS attribute their abdominal symptoms to food, and in fact, certain foods ingested can cause exaggerated gastrointestinal complaints. The aim of this study was to evaluate the effect of a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (known as the low-FODMAP) diet with a limitation of Tryptophan (TRP) intake on the clinical symptoms of patients with IBS-D in relation to its metabolism along the serotonin and kynurenine pathways. This study enrolled 40 healthy people (controls) and 80 patients with IBS-D. The IBS-D patients were randomly divided into two groups of 40 each (Groups IIA and IIB). In Group IIA, the low-FODMAP diet was recommended, while in Group IIB, the same diet was recommended but with limited TRP intake for 8 weeks. Results showed that: - both groups did not differ in clinical parameters or daily TRP consumption. - all IBS-D patients in both subgroups showed similar severity of abdominal complaints as well as anxiety and depressive symptoms before nutritional intervention. - reducing the amount of TRP content in a low-FODMAP diet improves its effectiveness in the treatment of IBS-D patients. Authors concluded that lowering the tryptophan content of a low-FODMAP diet may be useful in treating diarrhoea-predominant irritable bowel syndrome.
Abstract
(1) Background: A low-FODMAP diet is often recommended in the treatment of irritable bowel syndrome, but it does not improve abdominal symptoms in all patients, and an alternative diet is desirable. The purpose of this study was to evaluate the efficacy of a low-FODMAP diet with a concomitant reduction in tryptophan (TRP) intake in irritable bowel syndrome with diarrhea predominance (IBS-D) in relation to its metabolism via the serotonin and kynurenine pathways. (2) Methods: 40 healthy people (Group I, Controls) and 80 patients with IBS-D were included in the study. IBS-D patients were randomly divided into two groups of 40 each (Groups IIA and IIB). In Group IIA, the low-FODMAP diet was recommended, while in Group IIB, the same diet was recommended but with limited TRP intake for 8 weeks. The TRP intake was analyzed with the use of the nutritional calculator. Abdominal complaints were assessed using the Gastrointestinal Symptom Rating Scale (GSRS-IBS), and psychological status was simultaneously determined using two scales: the Hamilton Anxiety Scale (HAM-A) and the Hamilton Depression Scale (HAM-D). TRP and its metabolites: 5-hydoxyindoleacetic acid (5-HIAA), kynurenine (KYN), kynurenic acid (KYNA), and quinolinic acid (QA) were measured in urine using liquid chromatography tandem mass spectrometry (LC-MS/MS). (3) Results: The consumption of TRP per mg/kg/b.w./24 h has decreased in Group IIA from 20.9 ± 2.39 to 17.45 ± 2.41 (16.5%) and in Group IIB from 21.3 ± 2.33 to 14.32 (34.4%). Significantly greater improvement was found after nutritional treatment in patients in Group IIB as compared to Group IIA (GSRS score: 38.1% vs. 49.8%; HAM-A: 38.7% vs. 49.9%; HAM-D: 13.8% vs. 35.0%; p < 0.01). Reducing TRP intake showed a negative correlation with the degree of improvement in the GSRS score. (4) Conclusions: Lowering the TRP content in a low-FODMAP diet may be useful in treating IBS-D.
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Effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 on Overweight and the Gut Microbiota in Humans: Randomized, Double-Blinded, Placebo-Controlled Clinical Trial.
Mo, SJ, Lee, K, Hong, HJ, Hong, DK, Jung, SH, Park, SD, Shim, JJ, Lee, JL
Nutrients. 2022;14(12)
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Probiotics are defined by the WHO as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Recent studies suggest that probiotics play a role as natural therapeutic supplements with the potential to improve lipid metabolism, and improve weight control through interventions that affect gut microbiome diversity. The aim of this study was to explore how Lactobacillus curvatus HY7601 (HY7601) and Lactobacillus plantarum KY1032 (KY1032) supplementation alleviate obesity by modulating the human gut microbiome. This study was a 12-week randomised, double-blind, placebo-controlled study on overweight and obese Koreans. Subjects (n =72) were randomly assigned to receive either probiotics or placebo. Results showed that probiotic supplementation with HY7601 and KY1032 decreased body weight, visceral fat mass, waist circumference, and increased adiponectin. Furthermore, these probiotics changed the bacterial gut microbiota characteristics associated with each obesity indicator. HY7601 and KY1032 exerted anti-obesity effects by regulating the gut microbiota composition. Authors conclude that HY7601 and KY1032 intake can alter the composition and diversity of the human gut microbiome, and thereby help prevent obesity and its associated metabolic syndrome.
Abstract
Obesity and overweight are closely related to diet, and the gut microbiota play an important role in body weight and human health. The aim of this study was to explore how Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 supplementation alleviate obesity by modulating the human gut microbiome. A randomized, double-blind, placebo-controlled study was conducted on 72 individuals with overweight. Over a 12-week period, probiotic groups consumed 1 × 1010 colony-forming units of HY7601 and KY1032, whereas the placebo group consumed the same product without probiotics. After treatment, the probiotic group displayed a reduction in body weight (p < 0.001), visceral fat mass (p < 0.025), and waist circumference (p < 0.007), and an increase in adiponectin (p < 0.046), compared with the placebo group. Additionally, HY7601 and KY1032 supplementation modulated bacterial gut microbiota characteristics and beta diversity by increasing Bifidobacteriaceae and Akkermansiaceae and decreasing Prevotellaceae and Selenomonadaceae. In summary, HY7601 and KY1032 probiotics exert anti-obesity effects by regulating the gut microbiota; hence, they have therapeutic potential for preventing or alleviating obesity and living with overweight.
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Effects of Synbiotic Supplement on Human Gut Microbiota, Body Composition and Weight Loss in Obesity.
Sergeev, IN, Aljutaily, T, Walton, G, Huarte, E
Nutrients. 2020;12(1)
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The gut microbiota plays a role in the development of obesity and associated diseases. Whilst energy-restricted, low-carbohydrate, high-protein diets can facilitate substantial weight-loss, they also have been linked to ill-effects and unfavourable changes in the gut microbiota from excess protein fermentation. Pro-and prebiotics (synbiotics) have become a promising intervention in the management of obesity. This small placebo-controlled clinical trial involved 20 obese adults following an energy-restricted (approx.950 kcal/day) low-carbohydrate, high-protein diet. The study examined whether a supplementary synbiotic contributed to additional changes in body composition and metabolic biomarkers. The synbiotic contained Lactobacilli spp. and Bifidobacteria spp. and a prebiotic mixture of galactooligosaccharides. Overall, at the end of the 3-month trial, there was no remarkable difference between the groups. Both experienced a significant and decreasing trend in body mass, waist circumference, body mass index, fat mass, fat percentage, and glucose level, affirming the known benefits of the described weight-loss diet. However, the synbiotic supplementation group had a greater decrease in HbA1C and significant alterations in gut microbiota, showing an increased abundance of gut bacteria associated with positive health effects. Due to the complexity of microbial species and host interactions, the authors advocate for more research to identify their significance and shed light on contradictory findings. This study identified that synbiotics may not contribute to additional changes in body composition when combined with an energy-restricted, low-carbohydrate, high-protein diet but they can offer additional health benefits by inducing favourable changes to the gut microbiota.
Abstract
Targeting gut microbiota with synbiotics (probiotic supplements containing prebiotic components) is emerging as a promising intervention in the comprehensive nutritional approach to reducing obesity. Weight loss resulting from low-carbohydrate high-protein diets can be significant but has also been linked to potentially negative health effects due to increased bacterial fermentation of undigested protein within the colon and subsequent changes in gut microbiota composition. Correcting obesity-induced disruption of gut microbiota with synbiotics can be more effective than supplementation with probiotics alone because prebiotic components of synbiotics support the growth and survival of positive bacteria therein. The purpose of this placebo-controlled intervention clinical trial was to evaluate the effects of a synbiotic supplement on the composition, richness and diversity of gut microbiota and associations of microbial species with body composition parameters and biomarkers of obesity in human subjects participating in a weight loss program. The probiotic component of the synbiotic used in the study contained Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, and Bifidobacterium bifidum and the prebiotic component was a galactooligosaccharide mixture. The results showed no statistically significant differences in body composition (body mass, BMI, body fat mass, body fat percentage, body lean mass, and bone mineral content) between the placebo and synbiotic groups at the end of the clinical trial (3-month intervention, 20 human subjects participating in weight loss intervention based on a low-carbohydrate, high-protein, reduced energy diet). Synbiotic supplementation increased the abundance of gut bacteria associated with positive health effects, especially Bifidobacterium and Lactobacillus, and it also appeared to increase the gut microbiota richness. A decreasing trend in the gut microbiota diversity in the placebo and synbiotic groups was observed at the end of trial, which may imply the effect of the high-protein low-carbohydrate diet used in the weight loss program. Regression analysis performed to correlate abundance of species following supplementation with body composition parameters and biomarkers of obesity found an association between a decrease over time in blood glucose and an increase in Lactobacillus abundance, particularly in the synbiotic group. However, the decrease over time in body mass, BMI, waist circumstance, and body fat mass was associated with a decrease in Bifidobacterium abundance. The results obtained support the conclusion that synbiotic supplement used in this clinical trial modulates human gut microbiota by increasing abundance of potentially beneficial microbial species.
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Whole grain-rich diet reduces body weight and systemic low-grade inflammation without inducing major changes of the gut microbiome: a randomised cross-over trial.
Roager, HM, Vogt, JK, Kristensen, M, Hansen, LBS, Ibrügger, S, Mærkedahl, RB, Bahl, MI, Lind, MV, Nielsen, RL, Frøkiær, H, et al
Gut. 2019;68(1):83-93
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Whole grain consumption has been linked with decreased risk of lifestyle-related diseases. While animal studies have shown the gut microbiome to be a mediator of metabolic health, human studies examining the effect of whole grain intake of the gut remain inconclusive. The aim of this study was to investigate the effects of a whole grain diet on the gut microbiome, gut functionality and biomarkers of metabolic health. In this randomised, controlled, crossover study, 50 participants completed two 8-week dietary intervention periods comprising of a whole grain diet and a refined grain diet with a 6-week washout period. Examinations were done at the beginning and end of each intervention period to assess anthropometry and various plasma and gut markers. This study found that a whole grain diet as compared with a refined grain diet reduced energy intake and body weight as well as circulating markers of inflammation. Contrary to the hypothesis, these benefits were all observed independent of changes in the gut microbiome. Based on these results, the authors conclude higher intake of whole grains should be recommended to those at risk of inflammation-related disease.
Abstract
OBJECTIVE To investigate whether a whole grain diet alters the gut microbiome and insulin sensitivity, as well as biomarkers of metabolic health and gut functionality. DESIGN 60 Danish adults at risk of developing metabolic syndrome were included in a randomised cross-over trial with two 8-week dietary intervention periods comprising whole grain diet and refined grain diet, separated by a washout period of ≥6 weeks. The response to the interventions on the gut microbiome composition and insulin sensitivity as well on measures of glucose and lipid metabolism, gut functionality, inflammatory markers, anthropometry and urine metabolomics were assessed. RESULTS 50 participants completed both periods with a whole grain intake of 179±50 g/day and 13±10 g/day in the whole grain and refined grain period, respectively. Compliance was confirmed by a difference in plasma alkylresorcinols (p<0.0001). Compared with refined grain, whole grain did not significantly alter glucose homeostasis and did not induce major changes in the faecal microbiome. Also, breath hydrogen levels, plasma short-chain fatty acids, intestinal integrity and intestinal transit time were not affected. The whole grain diet did, however, compared with the refined grain diet, decrease body weight (p<0.0001), serum inflammatory markers, interleukin (IL)-6 (p=0.009) and C-reactive protein (p=0.003). The reduction in body weight was consistent with a reduction in energy intake, and IL-6 reduction was associated with the amount of whole grain consumed, in particular with intake of rye. CONCLUSION Compared with refined grain diet, whole grain diet did not alter insulin sensitivity and gut microbiome but reduced body weight and systemic low-grade inflammation. TRIAL REGISTRATION NUMBER NCT01731366; Results.
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Role of whole grains versus fruits and vegetables in reducing subclinical inflammation and promoting gastrointestinal health in individuals affected by overweight and obesity: a randomized controlled trial.
Kopf, JC, Suhr, MJ, Clarke, J, Eyun, SI, Riethoven, JM, Ramer-Tait, AE, Rose, DJ
Nutrition journal. 2018;17(1):72
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Poor diet is the leading risk factor for premature death and disability in the United States. Poor diets lead to metabolic syndrome and its associated diseases such as heart disease and diabetes. The purpose of this study was to determine the impact of increasing intake of wholegrains or fruit and vegetables against a typical Western diet on inflammatory makers and gut microbiota composition. The study was a randomized, parallel arm feeding trial which enrolled fifty-two participants. The subjects were randomized into three groups (control, wholegrains, and fruit and vegetables). Results indicate that the wholegrain and fruit and vegetable diets had significant positive impacts on inflammatory markers. Interestingly, while both treatment groups decreased inflammatory markers, each decreased a different biomarker. The treatments induced individualised changes in microbiota composition such that treatment group differences were not identified. Authors conclude that wholegrain and fruit and vegetable diets have a positive impact on metabolic health in individuals affected by overweight or obesity.
Abstract
BACKGROUND Whole grains (WG) and fruits and vegetables (FV) have been shown to reduce the risk of metabolic disease, possibly via modulation of the gut microbiota. The purpose of this study was to determine the impact of increasing intake of either WG or FV on inflammatory markers and gut microbiota composition. METHODS A randomized parallel arm feeding trial was completed on forty-nine subjects with overweight or obesity and low intakes of FV and WG. Individuals were randomized into three groups (3 servings/d provided): WG, FV, and a control (refined grains). Stool and blood samples were collected at the beginning of the study and after 6 weeks. Inflammatory markers [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP), and high sensitivity C-reactive protein (hs-CRP)] were measured. Stool sample analysis included short/branched chain fatty acids (S/BCFA) and microbiota composition. RESULTS There was a significant decrease in LBP for participants on the WG (- 0.2 μg/mL, p = 0.02) and FV (- 0.2 μg/mL, p = 0.005) diets, with no change in those on the control diet (0.1 μg/mL, p = 0.08). The FV diet induced a significant change in IL-6 (- 1.5 pg/mL, p = 0.006), but no significant change was observed for the other treatments (control, - 0.009 pg/mL, p = 0.99; WG, - 0.29, p = 0.68). The WG diet resulted in a significant decrease in TNF-α (- 3.7 pg/mL; p < 0.001), whereas no significant effects were found for those on the other diets (control, - 0.6 pg/mL, p = 0.6; FV, - 1.4 pg/mL, p = 0.2). The treatments induced individualized changes in microbiota composition such that treatment group differences were not identified, except for a significant increase in α-diversity in the FV group. The proportions of Clostridiales (Firmicutes phylum) at baseline were correlated with the magnitude of change in LBP during the study. CONCLUSIONS These data demonstrate that WG and FV intake can have positive effects on metabolic health; however, different markers of inflammation were reduced on each diet suggesting that the anti-inflammatory effects were facilitated via different mechanisms. The anti-inflammatory effects were not related to changes in gut microbiota composition during the intervention, but were correlated with microbiota composition at baseline. TRIAL REGISTRATION ClinicalTrials.gov , NCT02602496 , Nov 4, 2017.