11 research outputs found
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Impact of dietary supplementation with resistant dextrin (NUTRIOSE®) on satiety, glycaemia, and related endpoints, in healthy adults
Purpose
Resistant dextrin (RD) supplementation has been shown to alter satiety, glycaemia, and body weight, in overweight Chinese men; however, there are limited data on its effects in other demographic groups. Here, we investigated the effects of RD on satiety in healthy adults living in the United Kingdom.
Methods
20 normal weight and 16 overweight adults completed this randomised controlled cross-over study. Either RD (14 g/day NUTRIOSE® FB06) or maltodextrin control was consumed in mid-morning and mid-afternoon preload beverages over a 28-day treatment period with crossover after a 28-day washout. During 10-h study visits (on days 1, 14, and 28 of each treatment period), satietogenic, glycaemic and anorectic hormonal responses to provided meals were assessed.
Results
Chronic supplementation with RD was associated with higher fasted satiety scores at day 14 (P = 0.006) and day 28 (P = 0.040), compared to control. RD also increased satiety after the mid-morning intervention drink, but it was associated with a reduction in post-meal satiety following both the lunch and evening meals (P < 0.01). The glycaemic response to the mid-morning intervention drink (0–30 min) was attenuated following RD supplementation (P < 0.01). Whilst not a primary endpoint we also observed lower systolic blood pressure at day 14 (P = 0.035) and 28 (P = 0.030), compared to day 1, following RD supplementation in the normal weight group. Energy intake and anthropometrics were unaffected.
Conclusions
RD supplementation modified satiety and glycaemic responses in this cohort, further studies are required to determine longer-term effects on body weight control and metabolic markers
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In Vitro Fermentation of NUTRIOSE® FB06, a wheat dextrin soluble fibre, in a continuous culture human colonic model system
Wheat dextrin soluble fibre may have metabolic and health benefits, potentially acting via mechanisms governed by the selective modulation of the human gut microbiota. Our aim was to examine the impact of wheat dextrin on the composition and metabolic activity of the gut microbiota. We used a validated in vitro three-stage continuous culture human colonic model (gut model) system comprised of vessels simulating anatomical regions of the human colon. To mimic human ingestion, 7 g of wheat dextrin (NUTRIOSE® FB06) was administered to three gut models, twice daily at 10.00 and 15.00, for a total of 18 days. Samples were collected and analysed for microbial composition and organic acid concentrations by 16S rRNA-based fluorescence in situ hybridisation and gas chromatography approaches, respectively. Wheat dextrin mediated a significant increase in total bacteria in vessels simulating the transverse and distal colon, and a significant increase in key butyrate-producing bacteria Clostridium cluster XIVa and Roseburia genus in all vessels of the gut model. The production of principal short-chain fatty acids, acetate, propionate and butyrate, which have been purported to have protective, trophic and metabolic host benefits, were increased. Specifically, wheat dextrin fermentation had a significant butyrogenic effect in all vessels of the gut model and significantly increased production of acetate (vessels 2 and 3) and propionate (vessel 3), simulating the transverse and distal regions of the human colon, respectively. In conclusion, wheat dextrin NUTRIOSE® FB06 is selectively fermented in vitro by Clostridium cluster XIVa and Roseburia genus and beneficially alters the metabolic profile of the human gut microbiota
Genetic mechanisms of critical illness in COVID-19.
Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 × 10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice
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Investigating the effects of resistant dextrin, NUTRIOSE® FBOG, on the gut microbiota, host metabolism and appetite regulation
Dietary intake of resistant dextrin may alter gut microbial composition, appetite regulation, glucose homeostasis, and anthropometric measures. To date, much of the research has been conducted on overweight Asian individuals and there is a lack of information on the in vitro and in vivo effects in Western populations. The research presented in this PhD thesis consists of an in vitro, pilot, and human intervention study. The in vitro study utilised a three-stage gut model system, to which 14g/day resistant dextrin, NUTRIOSE® FB0G, was administered for 18 days. The pilot study was undertaken to determine feasibility, and optimise methods, for the main human intervention study. In the main human intervention study, 36 normal weight or overweight participants consumed 14g/day of NUTRIOSE® FB0G or control for 28 days in a crossover design. Resistant dextrin increased total bacteria, Clostridium cluster XIVa, Roseburia genus, and short chain fatty acid production in the gut model system (P<O.Ol). In vivo, resistant dextrin intake increased faecal Clostridium cluster IX (P=O.OOl) and propionate (P=O.049), in both normal weight and overweight individuals, and increased ß-glucosidase activity in normal weight participants (P=O.OOl). Resistant dextrin intake increased fasting satiety ratings (P=O.036), and responses to a morning preload, but resulted in a transient reduction following lunch and evening meals (P<O.05). Moreover, glucose and glucose-dependent insulinotropic peptide (GIP) responses to a morning preload were reduced (P<O.05). Effects on satiety were found in normal weight but not overweight participants. No differences in energy intake or body composition were found, however, resistant dextrin intake lowered systolic blood pressure in normal weight participants (P=O.030). In conclusion, resistant dextrin favourably modified gut microbiology, including elevated propionate production in vitro, and in normal weight and overweight humans. Furthermore, resistant dextrin intake altered satiety, glucose and hormone responses in vivo, however, specific effects differed between BMI groups
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Potential anti-obesogenic properties of non-digestible carbohydrates: specific focus on resistant dextrin
Alterations in the composition and metabolic activity of the gut microbiota appear to contribute to the development of obesity and associated metabolic diseases. However, the extent of this relationship remains unknown. Modulating the gut microbiota with non-digestible carbohydrates (NDC) may exert anti-obesogenic effects through various metabolic pathways including changes to appetite regulation, glucose and lipid metabolism and inflammation. The NDC vary in physicochemical structure and this may govern their physical properties and fermentation by specific gut bacterial populations. Much research in this area has focused on established prebiotics, especially fructans (i.e. inulin and fructo-oligosaccharides); however, there is increasing interest in the metabolic effects of other NDC, such as resistant dextrin. Data presented in this review provide evidence from mechanistic and intervention studies that certain fermentable NDC, including resistant dextrin, are able to modulate the gut microbiota and may alter metabolic process associated with obesity, including appetite regulation, energy and lipid metabolism and inflammation. To confirm these effects and elucidate the responsible mechanisms, further well-controlled human intervention studies are required to investigate the impact of NDC on the composition and function of the gut microbiota and at the same time determine concomitant effects on host metabolism and physiology
Bacterial populations.
<p>Bacterial populations in the three different vessels (V1, V2 and V3) of the gut models before (SS1) and after (SS2) WD treatment. Data presented as means of the three gut models ± standard deviations. SS1 and SS2 are calculated as mean values over three consecutive days. ** <i>P</i> < 0.01, *** <i>P</i> < 0.001, **** <i>P</i> < 0.0001, significantly different from SS1.</p
Mapping the human genetic architecture of COVID-19
The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3–7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease