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The Role of Lung and Gut Microbiota in the Pathology of Asthma.
Barcik, W, Boutin, RCT, Sokolowska, M, Finlay, BB
Immunity. 2020;52(2):241-255
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Over 300 million people suffer with asthma worldwide and it has emerged that microbiome analysis of the lung and gut bacteria, fungi, viruses, and archaea may help with disease management. This microbiome plays an important role in immune response. Disturbances to these microbes, known as dysbiosis, may influence onset of disease and the body’s ability to respond naturally, and/or to pharmaceutical treatments. Asthma is not a singular disease and there are great variations in symptom severity and underlying immune mechanisms. Patients are typically classified as type 2 or non-type 2. Type 2 patients tend to be allergic to common air-born allergens which can trigger an attack. Treatment usually consists of glucocorticosteroids or novel biologicals. Non type-2 asthma is associated with obesity-related asthma and typically responds poorly to steroid treatment. For a long time, researchers believed the human lungs to be sterile, so they were initially not included in the 2007 Human Microbiome Project. It has since been shown that, like the gut, the lungs and respiratory tract also host various microbes, and this healthy-airway microbiota influence innate and adaptive immune processes. The Gut-Lung axis also confers additional microbial benefits from the intestines. In asthma patients, there is often an over-dominance of pathogenic bacteria. Fungal dysbiosis is associated with high-risk asthma phenotypes in childhood. Viral infections have been shown as a primary cause of asthmatic episodes. Future diagnosis and treatment of patients with asthma should be assisted by analysis of the composition and metabolic activity of an individual’s microbiome.
Abstract
Asthma is a common chronic respiratory disease affecting more than 300 million people worldwide. Clinical features of asthma and its immunological and molecular etiology vary significantly among patients. An understanding of the complexities of asthma has evolved to the point where precision medicine approaches, including microbiome analysis, are being increasingly recognized as an important part of disease management. Lung and gut microbiota play several important roles in the development, regulation, and maintenance of healthy immune responses. Dysbiosis and subsequent dysregulation of microbiota-related immunological processes affect the onset of the disease, its clinical characteristics, and responses to treatment. Bacteria and viruses are the most extensively studied microorganisms relating to asthma pathogenesis, but other microbes, including fungi and even archaea, can potently influence airway inflammation. This review focuses on recently discovered connections between lung and gut microbiota, including bacteria, fungi, viruses, and archaea, and their influence on asthma.
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Links between metabolic syndrome and the microbiome.
Gildner, TE
Evolution, medicine, and public health. 2020;2020(1):45-46
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Metabolic syndrome (MetS) is a cluster of co-occurring pathological conditions, characterised by insulin resistance, abdominal obesity, hypertension and dyslipidaemia One possible factor contributing to MetS risk is change in microbiome composition. Diets high in processed foods appear to alter microbiome composition in ways that promote higher fat mass and insulin resistance. Additionally, a sedentary lifestyle decreases microbiome diversity, elevating inflammation and metabolic disease risk. Research on how the microbiome responds to modest, attainable changes in diet and physical activity will help identify which dietary adjustments and exercise types have the greatest potential to protect patients from MetS.
Abstract
Metabolic syndrome (MetS) is a cluster of harmful conditions which occur together, such as insulin resistance, abdominal obesity, and hypertension. The global prevalence of MetS is growing rapidly, with some estimates suggesting over one billion people worldwide experience increased morality and disease rates linked with this syndrome. One possible factor contributing to MetS risk is changes in microbiome composition. Approximately 100 trillion bacteria and other microbes reside in the human intestinal tract, collectively termed the gut microbiome. Humans and microbes share a long evolutionary history, with many of these microbes influencing human health outcomes. However, environmental conditions have changed dramatically with human technological innovations; many of these changes (e.g., diets high in processed foods and sedentary lifestyles) appear to impact human-microbe relationships. In general, recent changes in diet and activity patterns have been linked to decreased microbiome diversity, elevating inflammation and metabolic disease risk and likely promoting the development of MetS. Targeting patient diet or exercise patterns may therefore help doctors better treat patients suffering from MetS. Still, additional work is needed to determine how the microbiome responds to changes in patient activity and diet patterns across culturally and biologically diverse human populations.
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Mediterranean diet intervention in overweight and obese subjects lowers plasma cholesterol and causes changes in the gut microbiome and metabolome independently of energy intake.
Meslier, V, Laiola, M, Roager, HM, De Filippis, F, Roume, H, Quinquis, B, Giacco, R, Mennella, I, Ferracane, R, Pons, N, et al
Gut. 2020;69(7):1258-1268
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Evidence suggests that the Mediterranean diet (MD) may help prevent cardiovascular disease (CVD). However, this could be influenced by an individual’s gut microbiome, highlighting a need for personalised nutrition practices. This randomised crossover control trial aimed to evaluate an 8-week personalised MD intervention in 82 overweight and obese subjects, who were at high risk of cardiovascular disease. The results showed that a personalised MD lowered cholesterol, regardless of the amount of energy consumed and the amount of exercise performed and relied upon adherence to the MD. Gut microbiome composition was altered by a MD and although markers for diabetes were not improved overall, there was an improvement in prediabetes in individuals with higher levels of Bacteroides species and lower levels of Prevotella species. It was concluded that a MD may reduce cholesterol and alter the gut microbiome to benefit cardiovascular health. Health professionals could use this study to switch patients to a MD whilst maintaining their energy intake to reduce cardiovascular risk. In order to see maximum benefit, it would be recommended to take a personalised approach and analyse an individual’s gut microbiome in order to tailor recommendations.
Abstract
OBJECTIVES This study aimed to explore the effects of an isocaloric Mediterranean diet (MD) intervention on metabolic health, gut microbiome and systemic metabolome in subjects with lifestyle risk factors for metabolic disease. DESIGN Eighty-two healthy overweight and obese subjects with a habitually low intake of fruit and vegetables and a sedentary lifestyle participated in a parallel 8-week randomised controlled trial. Forty-three participants consumed an MD tailored to their habitual energy intakes (MedD), and 39 maintained their regular diets (ConD). Dietary adherence, metabolic parameters, gut microbiome and systemic metabolome were monitored over the study period. RESULTS Increased MD adherence in the MedD group successfully reprogrammed subjects' intake of fibre and animal proteins. Compliance was confirmed by lowered levels of carnitine in plasma and urine. Significant reductions in plasma cholesterol (primary outcome) and faecal bile acids occurred in the MedD compared with the ConD group. Shotgun metagenomics showed gut microbiome changes that reflected individual MD adherence and increase in gene richness in participants who reduced systemic inflammation over the intervention. The MD intervention led to increased levels of the fibre-degrading Faecalibacterium prausnitzii and of genes for microbial carbohydrate degradation linked to butyrate metabolism. The dietary changes in the MedD group led to increased urinary urolithins, faecal bile acid degradation and insulin sensitivity that co-varied with specific microbial taxa. CONCLUSION Switching subjects to an MD while maintaining their energy intake reduced their blood cholesterol and caused multiple changes in their microbiome and metabolome that are relevant in future strategies for the improvement of metabolic health.
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Increased Colonic Permeability and Lifestyles as Contributing Factors to Obesity and Liver Steatosis.
Di Palo, DM, Garruti, G, Di Ciaula, A, Molina-Molina, E, Shanmugam, H, De Angelis, M, Portincasa, P
Nutrients. 2020;12(2)
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Intestinal permeability (IP) is dependent on the structure and function of the intestinal barrier. The gut barrier integrity is the result of ongoing equilibrium and crosstalk involving the microbiome, the mucus, the enterocytes [intestinal absorptive cells], the gut immune system, and the gut–vascular barrier. The main aim of this study was to explore the pan-enteric IP (stomach, small intestine, and colon) with respect to size and fat distribution, as well as the presence of liver steatosis. The study is a cohort study that examined 120 subjects (obese n = 45, overweight n=30, normal weight n = 45). Groups were gender-matched except for the prevalence of males in the overweight group. Results highlight the existence of an association between colonic (but not stomach and small intestinal) permeability, obesity, and liver steatosis. Findings show that: - liver steatosis was detected in 69 (57.5%) subjects, of which 36 (52%) were males. The prevalence of liver steatosis increased from 4% in normal weight subjects to 77%, and to 98% in overweight and obese subjects, respectively. - gastrointestinal permeability changed between age groups at every tract, whereas stomach and small intestine IP decreased with age. Furthermore, this finding also occurred in subjects aged over or equal to 65 years, with respect to colonic permeability. Authors conclude that further studies must evaluate the possibility of modulating colonic permeability to allow both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
Abstract
Intestinal permeability (IP) is essential in maintaining gut-metabolic functions in health. An unequivocal evaluation of IP, as marker of intestinal barrier integrity, however, is missing in health and in several diseases. We aimed to assess IP in the whole gastrointestinal tract according to body mass index (BMI) and liver steatosis. In 120 patients (61F:59M; mean age 45 ± SEM 1.2 years, range: 18-75), IP was distinctively studied by urine recovery of orally administered sucrose (SO, stomach), lactulose/mannitol ratio (LA/MA, small intestine), and sucralose (SA, colon). By triple quadrupole mass-spectrometry and high-performance liquid chromatography, we measured urinary recovery of saccharide probes. Subjects were stratified according to BMI as normal weight, overweight, and obesity, and answered questionnaires regarding dietary habits and adherence to the Mediterranean Diet. Liver steatosis was assessed by ultrasonography. IP at every gastrointestinal tract was similar in both sexes and decreased with age. Stomach and small intestinal permeability did not differ according to BMI. Colonic permeability increased with BMI, waist, neck, and hip circumferences and was significantly higher in obese than in lean subjects. As determined by logistic regression, the odds ratio (OR) of BMI increment was significantly higher in subjects in the highest tertile of sucralose excretion, also after adjusting for age and consumption of junk food. The presence of liver steatosis was associated with increased colonic permeability. Patients with lower score of adherence to Mediterranean diet had a higher score of 'junk food'. Intestinal permeability tended to increase in subjects with a lower adherence to Mediterranean diet. In conclusion, colonic (but not stomach and small intestinal) permeability seems to be linked to obesity and liver steatosis independently from dietary habits, age, and physical activity. The exact role of these last factors, however, requires specific studies focusing on intestinal permeability. Results should pave the way to both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
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Effects of Fecal Microbiome Transfer in Adolescents With Obesity: The Gut Bugs Randomized Controlled Trial.
Leong, KSW, Jayasinghe, TN, Wilson, BC, Derraik, JGB, Albert, BB, Chiavaroli, V, Svirskis, DM, Beck, KL, Conlon, CA, Jiang, Y, et al
JAMA network open. 2020;3(12):e2030415
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Obesity has become a global pandemic even in adolescents. Lifestyle interventions have had limited impact on this cohort and drugs targeting obesity are often unlicensed in children. The gut microbiome has a role in weight regulation and may be a new target in adolescents with obesity. This randomised control trial of 87 adolescents with obesity over 26 weeks, aimed to assess if faecal microbiome transfer (FMT), which is a method whereby faecal matter is transplanted from one person to another, can be used to treat obesity. The results showed that FMT did not have an effect on body mass index (BMI) and the intervention group had a marginally increased BMI after FMT. Other disorders associated with obesity such as blood sugar levels were also unaffected by FMT, however there was a reduction in fat storage around the middle. It was concluded that FMT alone is not adequate to improve obesity in adolescents, but may reduce fat stored around the middle. Healthcare professionals could use this study to understand that simply transplanting one person’s gut microbiome to another, may not be enough. Targeted personalised approaches may be required, however further research is needed.
Abstract
Importance: Treatment of pediatric obesity is challenging. Preclinical studies in mice indicated that weight and metabolism can be altered by gut microbiome manipulation. Objective: To assess efficacy of fecal microbiome transfer (FMT) to treat adolescent obesity and improve metabolism. Design, Setting, and Participants: This randomized, double-masked, placebo-controlled trial (October 2017-March 2019) with a 26-week follow-up was conducted among adolescents aged 14 to 18 years with a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 30 or more in Auckland, New Zealand. A total of 87 individuals took part-565 individuals responded to advertisements, 328 were ineligible, and 150 declined participation. Clinical data were analyzed from September 2019 to May 2020. Interventions: Single course of oral encapsulated fecal microbiome from 4 healthy lean donors of the same sex or saline placebo. Main Outcomes and Measures: Primary outcome was BMI standard deviation score at 6 weeks using intention-to-treat analysis. Secondary outcomes included body composition, cardiometabolic parameters, well-being, and gut microbiome composition. Results: Eighty-seven participants (59% female adolescents, mean [SD] age 17.2 [1.4] years) were randomized 1:1, in groups stratified by sex, to FMT (42 participants) or placebo (45 participants). There was no effect of FMT on BMI standard deviation score at 6 weeks (adjusted mean difference [aMD] -0.026; 95% CI -0.074, 0.022). Reductions in android-to-gynoid-fat ratio in the FMT vs placebo group were observed at 6, 12, and 26 weeks, with aMDs of -0.021 (95% CI, -0.041 to -0.001), -0.023 (95% CI, -0.043 to -0.003), and -0.029 (95% CI, -0.049 to -0.008), respectively. There were no observed effects on insulin sensitivity, liver function, lipid profile, inflammatory markers, blood pressure, total body fat percentage, gut health, and health-related quality of life. Gut microbiome profiling revealed a shift in community composition among the FMT group, maintained up to 12 weeks. In post-hoc exploratory analyses among participants with metabolic syndrome at baseline, FMT led to greater resolution of this condition (18 to 4) compared with placebo (13 to 10) by 26 weeks (adjusted odds ratio, 0.06; 95% CI, 0.01-0.45; P = .007). There were no serious adverse events recorded throughout the trial. Conclusions and Relevance: In this randomized clinical trial of adolescents with obesite, there was no effect of FMT on weight loss in adolescents with obesity, although a reduction in abdominal adiposity was observed. Post-hoc analyses indicated a resolution of undiagnosed metabolic syndrome with FMT among those with this condition. Further trials are needed to confirm these results and identify organisms and mechanisms responsible for mediating the observed benefits. Trial Registration: Australian New Zealand Clinical Trials Registry Identifier: ACTRN12615001351505.
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Non-nutritive Sweeteners and Their Associations with Obesity and Type 2 Diabetes.
Walbolt, J, Koh, Y
Journal of obesity & metabolic syndrome. 2020;29(2):114-123
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Nutritive sweeteners (NS) contribute to overall caloric intake, and their adverse effects on metabolic health are well known. Non-nutritive sweeteners (NNS) on the other hand, have negligible or no calorific value and are therefore used as replacement of NS to negate their associated health risks. Whilst the consumption of NNS has steadily increased over the recent years, so has the evidence questioning their benefits. Some research suggesting that NNS could be an indirect contributor to the development of metabolic diseases. This review presents a brief compilation of current knowledge relating to NNS and metabolic syndrome, obesity, type 2 diabetes, and cardiovascular disease. Summarised are findings from randomised controlled trials (RCT), prospective cohort studies, observations from animal studies and recent microbiome research. The authors noted that NNS frequently exerted negative influences on health in prospective cohort studies, which observed selected population groups over time. Whilst in controlled trials, NNS often showed neutral or positive health benefits. Following a discussion of possible causes leading to such variations and conflicting outcomes, the authors called for more carefully designed studies to evaluate NNS and their metabolic influences. For clinicians, it may be worth considering further evidence relating to the individual types of sweeteners when evaluating NNS and their risks and benefits on cardiometabolic health.
Abstract
Evidence linking the excessive consumption of nutritive sweeteners (NS) to adverse metabolic health outcomes has led to an increase in consumption of non-nutritive sweeteners (NNS), particularly among the obese and individuals with diabetes. NNS are characterized by having zero-to-negligible caloric load, while also having a sweet taste. They are utilized as a replacement for traditional NS to reduce energy intake and to limit carbohydrate-related negative health outcomes. However, recent studies have suggested that NNS may actually contribute to the development or worsening of metabolic diseases, including metabolic syndrome, obesity, type 2 diabetes, and cardiovascular disease. Thus, it is imperative to understand the NNS efficacy and the relationship between NNS and metabolic diseases.
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7.
Probiotics for Immunity – a Look at the Research
OptiBac Probiotics specialise entirely in probiotics. One of their core values is encouraging people to take health into their own hands in a responsible manner. Training and education is a cornerstone of this, and with their expertise, they hope to help raise awareness of probiotics and their potential to help change lives.
2020
Abstract
This blog post presents the evidence available about the links between the gut microbiome, probiotics and the human immune system. With a useful run through of the different aspects of our immune systems, it provides details of the evidence for specific probiotic strains and in what circumstances they can be effectively and safely used to boost immunity.
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8.
How to take care of your immune system
OptiBac Probiotics specialise entirely in probiotics. One of their core values is encouraging people to take health into their own hands in a responsible manner. Training and education is a cornerstone of this, and with their expertise, they hope to help raise awareness of probiotics and their potential to help change lives.
2020
Abstract
This blog post summaries some of the simple but powerful dietary and lifestyle measures that can be taken to support the immune system. It discusses the power of sleep, exercise and diet in relation to immunity and the importance of minimising levels of stress, alcohol and travel. With useful tips for each of these areas and an attractive infographic setting it out in an eye-catching visual, it is a great one for Nutrition Practitioners to share with clients through their own social media channels.
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9.
Gut-Brain Axis
OptiBac Probiotics specialise entirely in probiotics. One of their core values is encouraging people to take health into their own hands in a responsible manner. Training and education is a cornerstone of this, and with their expertise, they hope to help raise awareness of probiotics and their potential to help change lives.
2020
Abstract
The idea of a gut-brain axis is not new, however the science continues to grow on the mechanisms behind the link between these two organs. Against a background of the physical connection between the gut and brain, this blog post provides details of the way that the gut microbiome communicates with the brain, influencing levels of anxiety, sleep, behaviour and mood. With details of specific probiotic strains used in a trial on depression, a TED talk link given by Guilia Enders on this topic and plenty of references to the microbiome and mental health, this is a good read for Nutrition Practitioners exploring mental health and links to the gut.
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10.
Your Child's Microbiome: Dr Kate's Complete Guide
OptiBac Probiotics specialise entirely in probiotics. One of their core values is encouraging people to take health into their own hands in a responsible manner. Training and education is a cornerstone of this, and with their expertise, they hope to help raise awareness of probiotics and their potential to help change lives.
2020
Abstract
A healthy gut microbiome is important to many aspects of health, from digestion, immunity, energy and skin. This blogpost provides up-to-date information on children's microbiome health, exploring pregnancy, birth and the early years in detail and giving details of what can affect the microbiome and ways to support it. Nutrition Practitioners working with parents and children will find the infographic on Your Child's Microbiome included in this blogpost a useful clinical tool.