Journal of Sports Medicine / 2018 / Article / Tab 2

Review Article

Interactions of Gut Microbiota, Endotoxemia, Immune Function, and Diet in Exertional Heatstroke

Table 2

Human intestinal microbiota: phyla, metabolism, and potential biological functions.

Intestinal segmentPredominant bacterial Bacterial metabolismPotential biological functions of bacteria metabolites
Biochemical Metabolic intermediates &  



 Small intestine


 Firmicutes 
Bacteroidetes 

Actinobacteria


Resistant starches, dietary fiber (cellulose, pectin, inulin), carbohydrates, amino acids, lipids, triglycerides, carboxylic acids, creatine, pancreatic/gastrointestinal secretions, and mucus.

Complex carbohydrates, amino acids, lactic acid, ethanol, succinic acid, and formate produce short-chain fatty acids (SCFA; acetate, propionate, butyrate), branched-chain fatty acids (BCFA), CO2, H2, NH3, H2S, amines, phenols, biotin, and vitamins K, B1, B2, B6, B12.
Absorb fats and lipid-soluble vitamins, stimulate systemic hormones to regulate lipid and glucose homeostasis, energy regulation, modulate pro- and anti-inflammatory genes, strengthen epithelial permeability, regulate colon pH, inhibit pathogen growth, provide energy to luminal epithelium.
   

Large intestine
  

Bacteroidetes, Firmicutes, Proteobacteria

Notes. Inter-individual differences are great; composition of substrates, intermediates and products change along the course of the intestinal tract; the outer membrane of Proteobacteria is composed mostly of LPS; most SCFA exist in higher concentrations in the proximal (versus distal) colon; phyla differ markedly in proximal versus distal colon, in part due to differences in oxygen tension. Abbreviations: IM, intestinal microbiota; LPS, lipopolysaccharide. Sources: [135, 152, 154, 253, 319, 323327].

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