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Effects of Wholegrain Compared to Refined Grain Intake on Cardiometabolic Risk Markers, Gut Microbiota, and Gastrointestinal Symptoms in Children: A Randomized Crossover Trial.
Madsen, MTB, Landberg, R, Nielsen, DS, Zhang, Y, Anneberg, OMR, Lauritzen, L, Damsgaard, CT
The American journal of clinical nutrition. 2024;119(1):18-28
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High consumption of wholegrain foods has been linked to a lower risk of cardiovascular disease (CVD) and type 2 diabetes. Some trials have shown benefits to body weight, blood lipids and glucose homeostasis but most of these studies are with adults. Cardiometabolic disease begins in childhood therefore data is needed for this age group to back up dietary recommendations in order to prevent later development of cardiometabolic disease. The aim of this randomized crossover trial was to look at the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL), cholesterol and plasma insulin, other cardiometabolic markers, body composition, the composition of the gut microbiome and gastrointestinal symptoms in children with high body mass index (BMI). 55 healthy Danish children (aged 8 – 13) took part. They ate wholegrain oats and rye (WG) or refined grain products (RG) ad libtum for 8 weeks in random order. Measurements were taken at 0, 8 and 16 weeks. Compared with RG, WG reduced LDL cholesterol as well as total:high-density lipoprotein cholesterol and triacylglycerol. WG also modulated the abundance of specific types of gut bacteria, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. This study supports the recommendation to swap refined grain for wholegrain oats and rye in children. Further studies are needed.
Abstract
BACKGROUND Wholegrain intake is associated with lower risk of cardiometabolic diseases in adults, potentially via changes in the gut microbiota. Although cardiometabolic prevention should start early, we lack evidence on the effects in children. OBJECTIVES This study investigated the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL) cholesterol and plasma insulin (coprimary outcomes), other cardiometabolic markers, body composition, gut microbiota composition and metabolites, and gastrointestinal symptoms in children with high body mass index (BMI). METHODS In a randomized crossover trial, 55 healthy Danish 8- to 13-y-olds received wholegrain oats and rye ("WG") or refined grain ("RG") products ad libitum for 8 wk in random order. At 0, 8, and 16 wk, we measured anthropometry, body composition by dual-energy absorptiometry, and blood pressure. Fasting blood and fecal samples were collected for analysis of blood lipids, glucose homeostasis markers, gut microbiota, and short-chain fatty acids. Gut symptoms and stool characteristics were determined by questionnaires. Diet was assessed by 4-d dietary records and compliance by plasma alkylresorcinols (ARs). RESULTS Fifty-two children (95%) with a BMI z-score of 1.5 ± 0.6 (mean ± standard deviation) completed the study. They consumed 108 ± 38 and 3 ± 2 g/d wholegrain in the WG and RG period, which was verified by a profound difference in ARs (P < 0.001). Compared with RG, WG reduced LDL cholesterol by 0.14 (95% confidence interval: -0.24, -0.04) mmol/L (P = 0.009) and reduced total:high-density lipoprotein cholesterol (P < 0.001) and triacylglycerol (P = 0.048) without altering body composition or other cardiometabolic markers. WG also modulated the abundance of specific bacterial taxa, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. CONCLUSION High intake of wholegrain oats and rye reduced LDL cholesterol and triacylglycerol, modulated bacterial taxa, and increased beneficial metabolites in children. This supports recommendations of exchanging refined grain with wholegrain oats and rye among children. This trial was registered at clinicaltrials.gov as NCT04430465.
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Mining microbes for mental health: Determining the role of microbial metabolic pathways in human brain health and disease.
Spichak, S, Bastiaanssen, TFS, Berding, K, Vlckova, K, Clarke, G, Dinan, TG, Cryan, JF
Neuroscience and biobehavioral reviews. 2021;125:698-761
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The microbiota-gut-brain axis is an emerging area of focus for mental health and disease. Metabolic products from gut microbiota exert direct and indirect effects on the brain through various body systems. The aim of this study was to review the evidence on these metabolic pathways and utilise new predictive tools to assess metabolic signatures of various disease states. This review included 278 studies and, despite the weak evidence, identified new links between gut microbial metabolic pathways in schizophrenia, Alzheimer’s disease, and anxiety and depression. The authors conclude this review provides a novel approach for understanding the mechanisms behind the bidirectional communication between the gut and brain. They also suggest guidelines for analysing and interpreting metadata of human-microbiome-brain studies and provide a framework for better understanding these metabolic pathways in relation to the brain.
Abstract
There is increasing knowledge regarding the role of the microbiome in modulating the brain and behaviour. Indeed, the actions of microbial metabolites are key for appropriate gut-brain communication in humans. Among these metabolites, short-chain fatty acids, tryptophan, and bile acid metabolites/pathways show strong preclinical evidence for involvement in various aspects of brain function and behaviour. With the identification of neuroactive gut-brain modules, new predictive tools can be applied to existing datasets. We identified 278 studies relating to the human microbiota-gut-brain axis which included sequencing data. This spanned across psychiatric and neurological disorders with a small number also focused on normal behavioural development. With a consistent bioinformatics pipeline, thirty-five of these datasets were reanalysed from publicly available raw sequencing files and the remainder summarised and collated. Among the reanalysed studies, we uncovered evidence of disease-related alterations in microbial metabolic pathways in Alzheimer's Disease, schizophrenia, anxiety and depression. Amongst studies that could not be reanalysed, many sequencing and technical limitations hindered the discovery of specific biomarkers of microbes or metabolites conserved across studies. Future studies are warranted to confirm our findings. We also propose guidelines for future human microbiome analysis to increase reproducibility and consistency within the field.
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Disruption of the Gut Ecosystem by Antibiotics.
Yoon, MY, Yoon, SS
Yonsei medical journal. 2018;59(1):4-12
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The gut microbiome is a complex ecosystem of different micro-organisms, such as bacteria, viruses and fungi, living in the human intestines. It’s involved in numerous functions, such as extracting energy and nutrition from food, protecting against disease-causing microorganisms, and supporting the immune system of the host, and therefore affecting human health and disease. This paper is a review of studies on the effects of antibiotics on the gut microbiota. It outlines how different types of antibiotics can alter the intestinal environment and the composition of the microbes, resulting in various physiological changes that can trigger disease. Relevant mechanisms, such as inflammatory response and the use of intestinal nutrients by infectious bacteria are discussed. Finally, it discusses faecal microbiota transplantation (FMT) and probiotics as treatment approaches, aimed at restoring a disturbed intestinal environment.
Abstract
The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state.