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Gut microbiome - Coggle Diagram
Gut microbiome
Body systems and organs affected by microbiome
Appetite and SCFA production
Microbe-produced SCFA stimulate vagus nerve, reducing appetite
SCFA stimulate leptin secretion--> increase satiety
bind to receptor that slows gut motility, increasing transit time
Immune system
prompt immune cells to produce cytokines
Article 1: Bifidobacteria can protect from enteropathogenic infection through production of acetate
Mice colonized with beneficial bifidobacteria survived e. coli infection, while mice without it died
Beneficial bacteria colonizing gut prevents pathogenic bacteria and bacteria with LPS from colonizing
Gut-brain axis
Serotonin production: cells in the gut produce large amounts of serotonin--> signalling effect in the brain
Immune system: prompt immune cells to produce cytokines that can influence neurophysiology
Article 2: Butyrate, neuroepigenetics and the gut microbiome
Gut microbiota produce butyrate (SCFA) by fermenting fiber. Butyrate can protect the brain (blood brain barrier) and enhance plasticity in neurological disease models.
Biosynthesis and metabolism
Vitamins
Article 2: human gut microbiome viewed across age and geography
Gut microbes can synthesize some vitamins (e.g. vit K, cobalamin, folate, biotin, thiamine). Increases w/ age.
Short chain fatty acids
SCFA produced as a byproduct of metabolism of food (fiber, mono-,di-,oligosaccharides). SCFA metabolites can have effects on other body systems (e.g. neurology)
Fiber digestion
Gut microbes have enzymes the human digestive system doesn't have, so some are capable of digesting starches we can't, i.e. fiber and oligosaccharides
Dietary factors affecting microbiome
Plant-based diet vs. animal-based diet
People on plant based diets tend to have a more diverse gut microbiome than people who eat an animal -based diet
Plant based diets have higher amounts of fiber and beneficial phytochemicals than animal-based diets
Article 3: Human gut microbiome viewed across age and geography
Gut microbiome in fat-heavy diets (like animal-based diets) have greater abundance of vitamin-synthesizing bacteria and microbes involved in bile salt metabolism
Animal-based US diet: microbiome overrepresented bacteria involved in amino acid degradation and simple sugar metabolism. Corn/casava-rich Malawi and Amerindian diet: microbiome overrepresented bacteria that break down starch
Breastfed vs. formula fed
Breastfed infants have a more diverse gut microbiome than formula fed infants
Breast milk isn't sterile, so breastfed baby is exposed to a greater variety of bacteria than formula fed baby (impacts immune system through gut microbiome too)
Prebiotics
Diet provides food that is digestible by gut microbes but not necessarily digestible by humans (i.e. fiber, oligosaccharides).
Providing this "bacteria food" in sufficient amounts keeps gut bacteria healthy and abundant
Fat content of diet
Article 4: High-Fat Diet Determines the Composition of the Murine Gut Microbiome Independently of Obesity
When switched to a high fat diet, gut microbiomes of mice changed compared to the low fat diet regardless of obesity status.
Study indicates the fat content of the diet impacts the gut microbiome more than adiposity