Скачать книгу

divided into four parts. First, a general introduction to the basis of the host–microbiome and how various microbiomes interact with each other. Second, the varied diet–microbiome influence on different income, age, and location factors. The third subchapter 1.3 will look into the application of diet in shaping the microbiome to treat various diseases. Lastly, the global outlook of opportunities and challenges in microbiome data study to achieve global health.

      1.1.1 Microbiome Diversity in Human Body

      1.1.1.1 Oral Microbiome

Schematic illustration of the average adult human microbiota composition of five body sites and their dominant phyla.

      Source: Based on Zaura et al. [8], Moffatt et al. [9], Goodrich et al. [10], Grice et al. [11], and Hilt et al. [12].

      Thus, it is evident that the human oral microbiome plays an important role in shaping the initial gut microbiome, laying the foundation of the general microbiota composition upon entering the stable phase after the individual reaches over three years of age.

      1.1.1.2 Gastrointestinal Microbiome

      Gastric microbiota is generally known to be acid‐tolerant, where these microbes need to survive under low pH conditions (pH 1–5). In a healthy individual, metagenomic analysis of the gastric microbiota showed an average abundance of Firmicutes (29.6%), Bacteroidetes (46.8%), Actinobacteria (11%), and Proteobacteria (10%). Among these phyla, the predominant genus includes those from the acid‐tolerant Streptococci, Lactobacilli, Staphylococci, and Neisseria spp. [18, 19] Dysbiosis resulting from Helicobacter pylori infection showed a massive shift of Proteobacteria abundance accounting for 93–97% of the total microbiota count [19]. The pathogen H. pylori preferentially localize at the upper gastric mucosa perturbing the gastric microbiota by reducing the microbial diversity and is linked to medical problems such as gastritis, peptic ulcers, and cancer [20].

      The small intestine involved in nutrient absorption with a long, narrow, folded tube structure exhibits restricted nutrient accessibility to promote microbial growth. The primary composition of the small intestinal microbiota is from the Clostridium, Enterococcus, Oxalobacter, Streptococcus, and Veillonella genera. Despite the poor diversity, the microbiota composition fluctuates depending on the structure and the exposure to the digested chyme in the small intestine [21]. Most of the microbes colonizing the small intestine carry genes encoding for carbohydrate phosphotransferase that play a role in competitive carbohydrate uptake in the microbiome [22]. Dysbiosis in the small intestinal tract showing increased abundance of Bacteroides spp., Clostridium leptum, and Staphylococcus spp. is linked to pediatric celiac

Скачать книгу