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Mixed Tree Nuts, Cognition, and Gut Microbiota: A 4-Week, Placebo-Controlled, Randomized Crossover Trial in Healthy Nonelderly Adults.
Haskell-Ramsay, CF, Dodd, FL, Smith, D, Cuthbertson, L, Nelson, A, Lodge, JK, Jackson, PA
The Journal of nutrition. 2023;152(12):2778-2788
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Cognitive impairment is a growing worldwide health concern as our population ages. In the absence of effective pharmaceutical treatments, modifiable lifestyle factors such as nutrition represent crucial targets in preventing cognitive decline. The aim of this study was to investigate the cognitive and mood effects of mixed tree nut supplementation in healthy non-elderly adults aged 18 to 49 years. This study is a randomised, placebo-controlled, double-blind, counterbalanced crossover design. Participants (n = 81) were randomly assigned to one of the two groups; the treatment or placebo group. Results showed that nut consumption led to improved picture recognition in terms of increased accuracy and faster reaction time. Furthermore, there was an enrichment of an unclassified type of bacterial community (Lachnospiraceae) but limited changes to the urinary metabolome. On the other hand, supplementation with mixed nuts failed to evince effects on mood. Authors conclude by pointing out that their findings are attributed to a sample of healthy and nonelderly participants. Thus, more profound effects may be shown with higher quantities of nuts or in those at risk, such as those experiencing cognitive decline or in those suffering gut dysbiosis.
Abstract
BACKGROUND Beneficial effects of nut supplementation on cognitive function have previously been demonstrated in young and older adults. Alterations to gut microbiota have also been shown following tree nut consumption. However, no data exists on the effects of nuts on cognition and intestinal microbial communities assessed within the same study. OBJECTIVES The study aimed to examine the effects of daily consumption of tree nuts for 4 wk on cognitive function (primary outcome), mood, metabolomics, and gut microbial species (secondary outcomes) in healthy, nonelderly adults. METHODS This randomized, placebo-controlled, double-blind, counterbalanced crossover study assessed the effects of 4 wk of supplementation with 30 g/d mixed tree nuts versus placebo on cognition and mood in 79 healthy adults aged 18-49 y. Metabolic responses, gut bacterial community structure, and the potential for these to impact cognition were explored using a multi-omic approach. Bacterial community analysis was conducted in Quantitative Insights Into Microbial Ecology 2 (QIIME2). RESULTS Mixed model analysis indicated that nut consumption led to significant improvements to accuracy (placebo M = 92.2% compared with NUTS M = 94.5%; P = 0.019) and speed of response (placebo M = 788 ms compared with NUTS M = 757 ms; P = 0.004) on a picture recognition task. No significant changes to bacterial community α or β diversity were observed when comparing nut consumption to the placebo arm. However, an unclassified Lachnospiraceae amplicon sequence variant (ASV) was significantly enriched in participants when supplemented with nuts (P = 0.015). No correlations were observed between the changes to picture recognition and the changes to the unclassified Lachnospiraceae ASV. There were no significant changes to the urinary metabolome. CONCLUSIONS These findings indicate a positive effect of nut on cognition following only 4 wk of consumption in a healthy nonelderly sample, as well as upregulation of a microbial taxa associated with gut health. The effects appear to be independent of one another, but further exploration is required in those experiencing cognitive decline and/or gut dysbiosis.
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Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial.
Wood, E, Hein, S, Mesnage, R, Fernandes, F, Abhayaratne, N, Xu, Y, Zhang, Z, Bell, L, Williams, C, Rodriguez-Mateos, A
The American journal of clinical nutrition. 2023;117(6):1306-1319
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The risk of developing both cardiovascular and neurodegenerative diseases increases with aging. Growing evidence from epidemiological and human intervention trials indicates that (poly)phenols may have cardioprotective properties as well as the ability to improve cognitive function. The aim of this study was to investigate the effects of daily wild blueberry (WBB) (poly)phenol consumption on vascular function and cognitive performance in healthy older individuals. This study was a randomised, double-blinded, placebo-controlled parallel design study. A total of 61 healthy older individuals were recruited and randomly assigned to one of the two arms; placebo intervention or blueberry intervention group. Results showed that long-term consumption of a dietary achievable amount of WBB enhanced vascular and cognitive function in older adults. Authors conclude that gut microbiota and vascular blood flow may play important roles in mediating the cognitive benefits shown by the consumption of (poly)phenol-rich foods.
Abstract
BACKGROUND Evidence suggests that the intake of blueberry (poly)phenols is associated with improvements in vascular function and cognitive performance. Whether these cognitive effects are linked to increases in cerebral and vascular blood flow or changes in the gut microbiota is currently unknown. METHODS A double-blind, parallel randomized controlled trial was conducted in 61 healthy older individuals aged 65-80 y. Participants received either 26 g of freeze-dried wild blueberry (WBB) powder (302 mg anthocyanins) or a matched placebo (0 mg anthocyanins). Endothelial function measured by flow-mediated dilation (FMD), cognitive function, arterial stiffness, blood pressure (BP), cerebral blood flow (CBF), gut microbiome, and blood parameters were measured at baseline and 12 wk following daily consumption. Plasma and urinary (poly)phenol metabolites were analyzed using microelution solid-phase extraction coupled with liquid chromatography-mass spectrometry. RESULTS A significant increase in FMD and reduction in 24 h ambulatory systolic BP were found in the WBB group compared with the placebo group (0.86%; 95% CI: 0.56, 1.17, P < 0.001; -3.59 mmHg; 95% CI: -6.95, -0.23, P = 0.037; respectively). Enhanced immediate recall on the auditory verbal learning task, alongside better accuracy on a task-switch task was also found following WBB treatment compared with placebo (P < 0.05). Total 24 h urinary (poly)phenol excretion increased significantly in the WBB group compared with placebo. No changes in the CBF or gut microbiota composition were found. CONCLUSIONS Daily intake of WBB powder, equivalent to 178 g fresh weight, improves vascular and cognitive function and decreases 24 h ambulatory systolic BP in healthy older individuals. This suggests that WBB (poly)phenols may reduce future CVD risk in an older population and may improve episodic memory processes and executive functioning in older adults at risk for cognitive decline. Clinical Trial Registration number in clinicaltrials.gov: NCT04084457.
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Serum, Urine, and Fecal Metabolome Alterations in the Gut Microbiota in Response to Lifestyle Interventions in Pediatric Obesity: A Non-Randomized Clinical Trial.
Lee, Y, Cho, JY, Cho, KY
Nutrients. 2023;15(9)
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Paediatric obesity is linked to an increased risk of type 2 diabetes, hypertension, dyslipidaemia, and metabolic syndrome. Diverse evidence suggests that obesity is associated with alterations in the gut microbiota and its metabolites. The aim of this study was to understand the metabolic pathways underlying paediatric obesity and the effect of intervention, which could provide guidance for the treatment of obesity. This study was a non-randomised clinical trial which enrolled 50 children with obesity and 22 normal-weight children aged 7–18 years. Results showed that imbalances in microbiota and metabolites were associated with both obesity and response to the intervention. The most distinct metabolic alterations in the obese group were branched-chain amino acid and purine changes. Authors conclude that the findings of their study could be valuable for identifying novel targets and biomarkers for the treatment of obesity.
Abstract
Pediatric obesity is associated with alterations in the gut microbiota and its metabolites. However, how they influence obesity and the effect of lifestyle interventions remains unknown.. In this non-randomized clinical trial, we analyzed metabolomes and microbial features to understand the associated metabolic pathways and the effect of lifestyle interventions on pediatric obesity. Anthropometric/biochemical data and fasting serum, urine, and fecal samples were collected at baseline and after an eight-week, weight-reduction lifestyle modification program. Post-intervention, children with obesity were classified into responder and non-responder groups based on changes in total body fat. At baseline, serum L-isoleucine and uric acid levels were significantly higher in children with obesity compared with those in normal-weight children and were positively correlated with obesogenic genera. Taurodeoxycholic and tauromuricholic α + β acid levels decreased significantly with obesity and were negatively correlated with obesogenic genera. Branched-chain amino acid and purine metabolisms were distinguished metabolic pathways in the obese group. Post-intervention, urinary myristic acid levels decreased significantly in the responder group, showing a significant positive correlation with Bacteroides. Fatty acid biosynthesis decreased significantly in the responder group. Thus, lifestyle intervention with weight loss is associated with changes in fatty acid biosynthesis, and myristic acid is a possible therapeutic target for pediatric obesity.
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Impact of wheat aleurone on biomarkers of cardiovascular disease, gut microbiota and metabolites in adults with high body mass index: a double-blind, placebo-controlled, randomized clinical trial.
Fava, F, Ulaszewska, MM, Scholz, M, Stanstrup, J, Nissen, L, Mattivi, F, Vermeiren, J, Bosscher, D, Pedrolli, C, Tuohy, KM
European journal of nutrition. 2022;61(5):2651-2671
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Cross-sectional studies have shown that whole grain cereal consumption can reduce the risk of cardiovascular disease (CVD, as well as reduce systemic inflammation, which is linked to many chronic diet associated diseases. Aleurone is a wheat grain fraction composed of a single cell layer that constitutes the outermost portion of the endosperm and contains many of the beneficial substances. The primary aim of this study was to investigate the effect of aleurone consumption on plasma homocysteine concentrations in overweight/ obese subjects. Secondary aim was to measure the impact of chronic aleurone supplementation on markers of CVD risk and on the human gut microbiota and its metabolic output. This study is a placebo-controlled, randomised, double-blind parallel trial with 2 test foods, wheat aleurone-rich foods or placebo foods (cellulose). Participants (n=74) were randomised to receive the active supplementation (aleurone 27 g per day) or placebo for 4 consecutive weeks. Results show that although average plasma homocysteine levels decreased upon wheat aleurone supplementation treatment, this change was not statistically significant, and homocysteine levels did not differ between groups after intervention. Furthermore, there was a significant increase in bifidobacteria both over time and compared to the placebo. Several significant and useful biomarkers of wheat aleurone intake, all related to wheat polyphenol metabolism by the gut microbiota, were identified. Authors conclude that wheat aleurone supplementation has the potential to modulate the gut microbial metabolic output and increase faecal bifidobacterial abundance, but it does not impact plasma homocysteine or other CVD biomarkers.
Abstract
PURPOSE Aleurone is a cereal bran fraction containing a variety of beneficial nutrients including polyphenols, fibers, minerals and vitamins. Animal and human studies support the beneficial role of aleurone consumption in reducing cardiovascular disease (CVD) risk. Gut microbiota fiber fermentation, polyphenol metabolism and betaine/choline metabolism may in part contribute to the physiological effects of aleurone. As primary objective, this study evaluated whether wheat aleurone supplemented foods could modify plasma homocysteine. Secondary objectives included changes in CVD biomarkers, fecal microbiota composition and plasma/urine metabolite profiles. METHODS A parallel double-blind, placebo-controlled and randomized trial was carried out in two groups of obese/overweight subjects, matched for age, BMI and gender, consuming foods supplemented with either aleurone (27 g/day) (AL, n = 34) or cellulose (placebo treatment, PL, n = 33) for 4 weeks. RESULTS No significant changes in plasma homocysteine or other clinical markers were observed with either treatment. Dietary fiber intake increased after AL and PL, animal protein intake increased after PL treatment. We observed a significant increase in fecal Bifidobacterium spp with AL and Lactobacillus spp with both AL and PL, but overall fecal microbiota community structure changed little according to 16S rRNA metataxonomics. Metabolomics implicated microbial metabolism of aleurone polyphenols and revealed distinctive biomarkers of AL treatment, including alkylresorcinol, cinnamic, benzoic and ferulic acids, folic acid, fatty acids, benzoxazinoid and roasted aroma related metabolites. Correlation analysis highlighted bacterial genera potentially linked to urinary compounds derived from aleurone metabolism and clinical parameters. CONCLUSIONS Aleurone has potential to modulate the gut microbial metabolic output and increase fecal bifidobacterial abundance. However, in this study, aleurone did not impact on plasma homocysteine or other CVD biomarkers. TRIAL REGISTRATION The study was registered at ClinicalTrials.gov (NCT02067026) on the 17th February 2014.
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The effects of Aronia berry (poly)phenol supplementation on arterial function and the gut microbiome in middle aged men and women: Results from a randomized controlled trial.
Le Sayec, M, Xu, Y, Laiola, M, Gallego, FA, Katsikioti, D, Durbidge, C, Kivisild, U, Armes, S, Lecomte, M, Fança-Berthon, P, et al
Clinical nutrition (Edinburgh, Scotland). 2022;41(11):2549-2561
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Over the last decades, Aronia melanocarpa, or black chokeberry, has gained increased attention for its high content of (poly)phenols, and potential protection against chronic diseases such as cardiovascular disease and diabetes. The aim of this study was to investigate the effects of 12-week aronia berry (poly)phenol consumption on cardiometabolic health and gut microbiome composition in prehypertensive middle-aged adults. This study was a 2-arm, double-blind, parallel randomised controlled trial. Participants (n = 102; 47 men and 55 women) were assigned randomly to Aronia or control groups. Results showed that there were no significant effects in blood pressure (primary outcome), endothelial function or blood lipids. However, there was a significant improvement in 24-hour ambulatory arterial indices and significant changes in gut microbiome richness, functions and composition between Aronia and control groups. Authors conclude that future studies should be conducted to investigate whether aronia supplementation may be effective in other at-risk populations such as hypertensives or people with cardiovascular disease risk.
Abstract
BACKGROUND AND AIMS Berry (poly)phenol consumption has been associated with cardioprotective benefits, however little is known on the role the gut microbiome may play on such health benefits. Our objective was to investigate the effects of aronia berry (poly)phenol consumption on cardiometabolic health and gut microbiome richness and composition in prehypertensive middle-aged men and women. METHODS A total of 102 prehypertensive participants were included in a parallel 12-week randomized double-blind placebo-controlled trial. Volunteers were randomly allocated to daily consume an encapsulated (poly)phenol-rich aronia berry extract (Aronia, n = 51) or a matched maltodextrin placebo (Control, n = 51). Blood pressure (BP) and arterial function (office and 24 h), endothelial function (measured as flow-mediated dilation), serum biochemistry (including blood lipids), plasma and urine (poly)phenol metabolites as well as gut microbiome composition through shotgun metagenomic sequencing were monitored over the study period. Relationships between vascular outcomes, (poly)phenol metabolites and gut microbiome were investigated using an integrated multi-levels approach. RESULTS A significant improvement in arterial indices measured as augmentation index (AIx) and pulse wave velocity (PWV) was found in the Aronia compared to Control group (awake Δ PWV = -0.24 m/s; 95% CI: -0.79, -0.01 m/s, P < 0.05; 24 h peripheral Δ AIx = -6.8; -11.2, -2.3, %, P = 0.003; 24 h central Δ AIx = -3.3; -5.5, -1.0, %, P = 0.006). No changes in BP, endothelial function or blood lipids were found following the intervention. Consumption of aronia (poly)phenols led to a significant increase in gut microbiome gene richness and in the abundance of butyrate-producing species such as Lawsonibacter asaccharolyticus and Intestinimonas butyriciproducens species, compared to Control group. Results from an approach including metabolomic, metagenomic and clinical outcomes highlighted associations between aronia-derived phenolic metabolites, arterial stiffness, and gut microbiome. CONCLUSIONS Aronia berry (poly)phenol consumption improved arterial function in prehypertensive middle-aged individuals, possibly via modulation of gut microbiome richness and composition based on the associations observed between these parameters. CLINICAL TRIAL REGISTRY The National Institutes of Health (NIH)-randomized trial records held on the NIH ClinicalTrials.gov website (NCT03434574). Aronia Berry Consumption on Blood Pressure.
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Effects of Lactobacillus gasseri CP2305 on Mild Menopausal Symptoms in Middle-Aged Women.
Sawada, D, Sugawara, T, Hirota, T, Nakamura, Y
Nutrients. 2022;14(9)
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The gastrointestinal tract represents the largest interface and interaction between the host and microorganisms. This collection of microorganisms is called the enteric or gut microbiota, and co-evolved with their hosts in an intricate, mutually beneficial relationship. One of the most important interactions is the brain–gut interaction, which maintains both intestinal homeostasis and brain function. The aim of this study was to analyse the influence of Lactobacillus gasseri CP2305 (CP2305) intake on the hypothalamic– pituitary–gonadal axis and its effects on mild symptoms associated with menopause. This study was a double-blind, placebo-controlled, parallel-group clinical trial. The enrolled subjects were randomly assigned to either the CP2305 group or placebo group. Results showed that consumption of CP2305 improves mild psychological symptoms that are unique to menopausal women, and improves the most common vasomotor symptoms, such as hot flashes. Authors concluded that the consumption of CP2305 may be used as an alternative treatment to alleviate menopausal symptoms.
Abstract
Lactobacillus gasseri CP2305 (CP2305) is a paraprobiotic that exhibits beneficial effects on the intestinal function and microbiota, and increases resistance to psychological stress. The stress response mechanism mainly involves the hypothalamic-pituitary-adrenal axis, which is influenced by the gut-brain axis. Furthermore, the gut-brain axis also communicates bidirectionally with the intestinal microbiota. Additionally, the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes share a common route that affects both mental and health aspects in women. This double-blind, placebo-controlled, parallel-group clinical trial aimed to analyze the influence of the intake of CP2305 on mild symptoms associated with menopause. Eighty women aged 40-60 years ingested CP2305 or placebo tablets for six consecutive menstrual cycles. Assessment was based on the observation of climacteric symptoms with two validated questionnaires-the Simplified Menopausal Index (SMI) and the Greene Climacteric Scale (GCS). The results showed that CP2305 provided significant relief in the SMI total score, SMI vasomotor score, SMI psychological score, GCS total score, GCS somatic score, and GCS vasomotor score compared to the placebo. The percentage of women with symptom relief for the SMI total score was 75.0%, with 30 of 40 women in the CP2305 group, and 55.0%, with 22 of 40 women in the placebo group (p = 0.0594). These findings provide new insights into the function of paraprobiotic CP2305 in relieving mild climacteric symptoms in women.
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Effects of Probiotic NVP-1704 on Mental Health and Sleep in Healthy Adults: An 8-Week Randomized, Double-Blind, Placebo-Controlled Trial.
Lee, HJ, Hong, JK, Kim, JK, Kim, DH, Jang, SW, Han, SW, Yoon, IY
Nutrients. 2021;13(8)
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Dietary changes directly alter the gut microbiome composition. A diversified gut microbiome may have therapeutic implications for mental health, and specific strains of probiotics have shown the potential to treat depression and anxiety. Several preclinical trials have found the probiotic mixture NVP-1704 to alleviate depression and anxiety in mice through modulating the gut-brain-microbiome axis. The aim of this randomised, double-blind, placebo-controlled, parallel study was to examine the efficacy and safety of NVP-1704 for the management of depression, anxiety and insomnia in healthy adults. A total of 156 healthy adults with subclinical depression, anxiety and insomnia were randomised to receive either NVP-1704 or placebo for eight weeks. Participants completed various questionnaires and biomarkers of stress and inflammation were assessed. After eight weeks, this study found that NVP-1704 to be a safe and well-tolerated probiotic with beneficial effects on depression, sleep quality, inflammation and gut microbiome composition in healthy adults. Based on this study, the authors conclude the therapeutic effects of NVP-1704 previously found in preclinical mice trials may now be translated to clinical trials. The authors suggest large, highly controlled, longitudinal human studies be conducted in the future to further confirm the benefits of probiotics on mental health and sleep.
Abstract
The human gut microbiome is closely linked to mental health and sleep. We aimed to verify the efficacy and safety of probiotic NVP-1704, a mixture of Lactobacillus reuteri NK33 and Bifidobacterium adolescentis NK98, in improving stress, depression, anxiety, and sleep disturbances, along with the measurement of some blood biomarkers. A total of 156 healthy adults with subclinical symptoms of depression, anxiety, and insomnia were retrospectively registered and randomly assigned to receive either NVP-1704 (n = 78) or a placebo (n = 78) for eight weeks. Participants completed the Stress Response Inventory, Beck's Depression and Anxiety Inventory, Pittsburg Sleep Quality Index, and Insomnia Severity Index at baseline, at four and eight weeks of treatment. Pre- and post-treatment blood tests for biomarkers were conducted. After intervention, gut microbiota composition was quantified by pyrosequencing the bacterial 16S rRNA gene. The NVP-1704 group had a more significant reduction in depressive symptoms at four and eight weeks of treatment, and anxiety symptoms at four weeks compared to the placebo group. Those receiving NVP-1704 also experienced an improvement in sleep quality. NVP-1704 treatment led to a decrease in serum interleukin-6 levels. Furthermore, NVP-1704 increased Bifidobacteriaceae and Lactobacillacea, whereas it decreased Enterobacteriaceae in the gut microbiota composition. Our findings suggest that probiotic NVP-1704 could be beneficial for mental health and sleep.
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Moderate Consumption of Beer (with and without Ethanol) and Menopausal Symptoms: Results from a Parallel Clinical Trial in Postmenopausal Women.
Trius-Soler, M, Marhuenda-Muñoz, M, Laveriano-Santos, EP, Martínez-Huélamo, M, Sasot, G, Storniolo, CE, Estruch, R, Lamuela-Raventós, RM, Tresserra-Rimbau, A
Nutrients. 2021;13(7)
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During the menopause, hormonal changes can trigger uncomfortable symptoms such as hot flashes, night sweats, sleep disturbances, and vaginal dryness. Hormone replacement therapy does reduce some of the symptoms, however there has been an increased interest in alternative therapies such as phytoestrogens to relieve these symptoms. Phytoestrogens are compounds with oestrogen-like properties naturally found in plants. Beer is the main food source of the strongest phytoestrogen identified to date. The aim of this six-month parallel, controlled clinical intervention trial was to evaluate if a moderate daily intake of beer, with or without alcohol, could reduce menopausal symptoms in women. Female sex hormone profile and cardiovascular risk factors (CVRF) were also monitored. 34 postmenopausal women took part. One group included alcoholic beer (AB), and a second group added non-alcoholic beer (NAB) for 6 months. The control group took no alcohol in this time. After a 6-month follow-up both groups (AB and NAB) significantly reduced the severity of the menopause-related symptoms. These results must be considered as preliminary and will require confirmation with larger sample sizes.
Abstract
The menopausal transition can be a challenging period for women's health and a trigger of uncomfortable symptoms. Beer is the main food source of isoxanthohumol, a precursor of 8-prenylnaringenin, the strongest phytoestrogen identified to date. As phytoestrogens are reported to reduce perimenopausal symptoms, we evaluated if a daily moderate consumption of beer with (AB) and without alcohol (NAB) could improve menopausal symptoms and modify cardiovascular risk factors. A total of 37 postmenopausal women were enrolled in a parallel controlled intervention trial and assigned to three study groups: 16 were administered AB (330 mL/day), 7 NAB (660 mL/day), and 14 were in the control group. After a 6-month follow-up of the 34 participants who finished the trial, both interventions (AB and NAB) significantly reduced the severity of the menopause-related symptoms (p-value AB vs. Control: 0.009; p-value NAB vs. Control: 0.033). Moreover, AB had a beneficial net effect on psychological menopausal discomforts compared to the control group. As the sex hormone profile did not differ significantly between the study groups, the effects of both types of beers (AB and NAB) are attributed to the non-alcoholic fraction of beer. Furthermore, moderate NAB consumption improved the lipid profile and decreased blood pressure in postmenopausal women.
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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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Endothelial Function is improved by Inducing Microbial Polyamine Production in the Gut: A Randomized Placebo-Controlled Trial.
Matsumoto, M, Kitada, Y, Naito, Y
Nutrients. 2019;11(5)
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Endothelial dysfunction is an early warning sign for plaque formation in atherosclerosis. This study explores the Bifidobacterium animalis subsp. Lactis (Bifal) and arginine (Arg) on endothelial function in forty-four healthy subjects. The subjects were randomised to receive 100g daily of natural yoghurt containing Bifal and Arg, or a placebo, for a total of twelve weeks. In a precursor to this study, the authors found that Bifal and Arg increased the production of certain polyamines in the gut, essential to cell proliferation and inhibition of inflammation. They concluded that exogenous polyamines from foods may be of benefit to cardiovascular health. In this follow-up study they measured fecal, blood and urine samples to analyse polyamine concentration, bacterial DNA, serum polyamine, inflammatory cytokines, triglycerides and other biochemical parameters. The reactive hyperemia index (RHI), the primary outcome, was measured using endo-peripheral arterial tone (EndoPAT). The results showed that the participants who received the Bifal and Arg yoghurt saw their RHI increase from 1.50 to 1.81, suggesting that Bifal + Arg YG intake restored endothelial function to normal levels. The other biomarkers measured also suggested an improvement of vascular endothelial function with a reduction in serum platelet and triglyceride levels, two risk factors for atherosclerosis.
Abstract
Recently, it was demonstrated that spermidine-induced autophagy reduces the risk of cardiovascular disease in mice. Intestinal bacteria are a major source of polyamines, including spermidine. We previously reported that the intake of both Bifidobacterium animalis subsp. lactis (Bifal) and arginine (Arg) increases the production of putrescine, a spermidine precursor, in the gut. Here, we investigated the effects of Bifal and Arg consumption on endothelial function in healthy subjects. Healthy individuals with body mass index (BMI) near the maximum value in the "healthy" range (BMI: 25) (n = 44) were provided normal yogurt containing Bifal and Arg (Bifal + Arg YG) or placebo (normal yogurt) for 12 weeks in this randomized, double-blinded, placebo-controlled, parallel-group comparative study. The reactive hyperemia index (RHI), the primary outcome, was measured using endo-peripheral arterial tone (EndoPAT). The change in RHI from week 0 to 12 in the Bifal + Arg YG group was significantly higher than that in the placebo group, indicating that Bifal + Arg YG intake improved endothelial function. At week 12, the concentrations of fecal putrescine and serum putrescine and spermidine in the Bifal + Arg YG group were significantly higher than those in the placebo group. This study suggests that consuming Bifal + Arg YG prevents or reduces the risk of atherosclerosis.