Wellness influencers often talk about fixing a broken gut microbiome. And marketers sell tests and supplements to fix your gut health. Here's what what the evidence really shows about gut health.
A contributory citizen science project reveals the impact of dietary keys to microbiome health in Spain
Low consumption of whole grains, fruits, and vegetables has been identified as dietary risks for non-communicable diseases such as inflammatory bowel diseases (IBDs). We explore how individual and lifestyle factors influence these risks by shaping gut microbiome composition. 1001 healthy participants from all Spanish regions provided personal and dietary data at baseline, six, and twelve months, yielding 2475 responses. Gut microbiome data were analyzed for 500 healthy participants and 321 IBD patients. Our findings reveal that adherence to national dietary guidelines—characterized by diets rich in nuts, seeds, fruits, and vegetables—was associated with greater microbial diversity and reduced IBD-related dysbiosis. Finally, we observed variations in dietary patterns and microbiome diversity and composition across age groups, genders, regions, seasons, and transit time. This study is among the first to uncover dietary intake associated with IBD-related dysbiosis and to propose an interactive website for participants (https://manichanh.vhir.org/POP/en).
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A single fecal transplant linked to long-lasting health improvements
A single fecal microbiota transplant in obese teens was linked to long-lasting metabolic improvements, including smaller waistlines, reduced body fat, lower inflammation, and better cholesterol levels, with some benefits still evident four years later.
Regulation of Intestinal Barrier Function by Microbial Metabolites
The human gastrointestinal tract (GI) harbors a diverse population of microbial life that continually shapes host pathophysiological responses. Despite readily available abundant metagenomic data, the functional dynamics of gut microbiota remain to be explored in various health and disease conditions. Microbiota generate a variety of metabolites from dietary products that influence host health and pathophysiological functions. Since gut microbial metabolites are produced in close proximity to gut epithelium, presumably they have significant impact on gut barrier function and immune responses.
Gut microbiome atlas maps how bacteria establish themselves and shift in inflammatory bowel disease
Researchers created a microbiome-wide atlas mapping more than seven million colonization factor genes across 4,716 human gut microbial species, revealing three putative strategies linked to metabolism, stress resistance, and microbial communication. Applying the framework to inflammatory bowel disease showed that colonization-factor profiles can provide a compact, biologically interpretable view of disease-associated microbiome changes.
The mycobiome as integral part of the gut microbiome: crucial role of symbiotic fungi in health and disease
The gut mycobiome significantly affects host health and immunity. However, most studies have focused on symbiotic bacteria in the gut microbiome, whereas less attention has been given to symbiotic fungi. Although fungi constitute only 0.01%-0.1% of the gut microbiome, their larger size and unique immunoregulatory functions make them significant. Factors like diet, antimicrobials use, and age can disrupt the fungal community, leading to dysbiosis. Fungal-bacterial-host immune interactions are critical in maintaining gut homeostasis, with fungi playing a role in mediating immune responses such as Th17 cell activation. This review highlights methods for studying gut fungi, the composition and influencing factors of the gut mycobiome, and its potential in therapeutic interventions for intestinal and hepatic diseases. We aim to provide new insights into the underexplored role of gut fungi in human health.
The pleiotropic effects of prebiotic galacto-oligosaccharides on the aging gut
Prebiotic galacto-oligosaccharides (GOS) have an extensively demonstrated beneficial impact on intestinal health. In this study, we determined the impact of GOS diets on hallmarks of gut aging: microbiome dysbiosis, inflammation, and intestinal barrier defects (“leaky gut”). We also evaluated if short-term GOS feeding influenced how the aging gut responded to antibiotic challenges in a mouse model of Clostridioides difficile infection. Finally, we assessed if colonic organoids could reproduce the GOS responder—non-responder phenotypes observed in vivo.
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The contribution of gut bacterial metabolites in the human immune signaling pathway of non-communicable diseases
The interaction disorder between gut microbiota and its host has been documented in different non-communicable diseases (NCDs) such as metabolic syndrome, neurodegenerative disease, and autoimmune ...
Scientists discover a way to kill dangerous gut bacteria without killing the good
Scientists have discovered a natural compound that targets dangerous C. difficile bacteria without wiping out the gut's beneficial microbes. Successful early tests suggest it could lead to a gentler, more effective treatment for stubborn intestinal infections that frequently return.
Interactions between gut microbiota and skeletal muscle
The gut microbiota is now recognized as a major contributor to the host’s nutrition, metabolism, immunity, and neurological functions. Imbalanced microbiota (ie, dysbiosis) is linked to undernutrition-induced stunting, inflammatory and metabolic diseases, and cancers. Skeletal muscle also takes part in the interorgan crosstalk regulating substrate metabolism, immunity, and health. Here, we review the reciprocal influence of gut microbiota and skeletal muscle in relation to juvenile growth, performance, aging, and chronic diseases. Several routes involving the vascular system and organs such as the liver and adipose tissue connect the gut microbiota and skeletal muscle, with effects on fitness and health. Therapeutic perspectives arise from the health benefits observed with changes in gut microbiota and muscle activity, further encouraging multimodal therapeutic strategies.
Fecal transplants for autism deliver success in clinical trials
Scientific research continues to uncover interesting connections between the gut microbiome and human health, including everything from depression to PTSD to autoimmune disease. Another example of this are emerging ties between gut health and autism. Exciting new research, now moving to Phase 3 human trials, has found boosting microbial diversity via fecal transplants can dramatically reduce autism symptoms in the long term.
Microbiome transplants may curb food allergies
Gut microbe transplants treated some peanut allergies in an early-stage clinical trial.
The gut-bone axis: how bacterial metabolites bridge the distance
1Department of Internal Medicine 3, Rheumatology and Immunology, Friedrich-Alexander University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany.
The Microbial Metabolites, Short-Chain Fatty Acids, Regulate Colonic T<sub>reg</sub> Cell Homeostasis
Protecting the Guts Regulatory T cells (T regs ) in the gut are important sentinels in maintaining the peace between our gut and its trillions of resident bacteria and have been shown to be regulated by specific strains of bacteria in mouse models. Smith et al. (p. 569 , published online 4 July; see the Perspective by Bollrath and Powrie ) asked whether metabolite(s) generated by resident bacterial species may regulate T regs in the gut. Indeed, short-chain fatty acids (SCFAs), bacterial fermentation products of dietary fibers produced by a range of bacteria, restored colonic T reg numbers in mice devoid of a gut microbiota and increased T reg numbers in colonized mice. The effects of SCFAs on T regs were mediated through GPCR43, a receptor for SCFAs, which is expressed on colonic T regs . Mice fed SCFAs were protected against experimentally induced colitis in a manner that was dependent on GPR43-expressing T regs . , Bacterial fermentation products regulate the number and function of regulatory T cells in the mouse colon. [Also see Perspective by Bollrath and Powrie ] , Regulatory T cells (T regs ) that express the transcription factor Foxp3 are critical for regulating intestinal inflammation. Candidate microbe approaches have identified bacterial species and strain-specific molecules that can affect intestinal immune responses, including species that modulate T reg responses. Because neither all humans nor mice harbor the same bacterial strains, we posited that more prevalent factors exist that regulate the number and function of colonic T regs . We determined that short-chain fatty acids, gut microbiota–derived bacterial fermentation products, regulate the size and function of the colonic T reg pool and protect against colitis in a Ffar2 -dependent manner in mice. Our study reveals that a class of abundant microbial metabolites underlies adaptive immune microbiota coadaptation and promotes colonic homeostasis and health.
A challenge if anyone wants to take it up. Here is a recent review in the BMJ on the "Evidence for clinical interventions targeting the gut microbiome in cardiometabolic disease". There is not a single effect estimate reported in this review, or either supplemental file bmj.com/content/383/bmj-2023-075180
Evidence for clinical interventions targeting the gut microbiome in cardiometabolic disease
www.bmj.com