The definition of our
human body as a “superorganism” is based on the fact that our body resides a
large collection of microorganisms, which play an important role in the health
of the human body. All the genomic elements of these microorganisms together
are marked as microbiome. (1) For an analysis of the
human genetics to the full extent, it is necessary to examine the genes in the
human genome, as well as identify the microbiome (2). Most of the microbiota
in the human body can be found in the gastrointestinal tract (1).
Determination of the gut microbiome
Traditionally, the investigation of microbial communities has been dependent on
cultivation techniques. For the gut microbiome, these techniques do not provide
satisfactory findings. A better approach to identify the composition of the
gut microbiome is through culture-independent metagenomic investigations in
combination with 16s rDNA sequence analysis. The aim of this method is to provide
an extensive view of the whole genetics from a community, which is accomplished
through the primarily random sequencing of all DNA and later sequencing of the
16s rRNA-encoding gene. (3) This method not only allows to determine how many,
but also which microbes exactly are present in the given microbial community (4).
Structure and dominant organisms
To fully understand the impact of the gut
microbiome on our health it is important to know how it is structured. For the
most part the gut microbiome consists of bacteria, but there are also archaea,
fungi, viruses and protozoa present (4). An average healthy adult houses more
than 1000 species of bacteria, the phyla Firmicutes and Bacteroidetes being the
most dominant (5). The highest density of organisms can be found in the lower
gastro intestinal tract (6). The composition of the different species can vary
greatly between different healthy people, but the species are likely stable
throughout a healthy individual’s lifetime (5).
Function in the human body
Without microbial activities
in the gut, nutrition and digestion would not be possible (5). The gut
microbiome fulfils various metabolic tasks like the production of vitamins and
the synthesis of essential and nonessential amino acids. Another important
function of the gut microbiome is the production of antimicrobial compounds, so
it play an important role in the development our immune system as well. In many
different studies, it has been elaborated that there is an association between
the gut microbiota and chronic gastrointestinal diseases and systemic metabolic
diseases like diabetes and obesity. (7)
The importance of the gut microbiome in life
While researching for this blog entry, I
came across a large number of different scientific papers about the influence
of the gut microbiome on our body. One thing they all had in common was the
conclusion that further investigation is necessary to fully understand the role
of the gut microbiome. The findings of the research seem comprehensible to me
and I do believe in a close relationship between the gut microbiome and our
health. One of the remaining questions is whether we are able to influence the
composition of our microbiome - and therefore our health - by the consumption
of probiotic microorganisms and our diet in general.
References:
(1) D’Argenio, V., & Salvatore, F. (2015). The
role of the gut microbiome in the healthy adult status. Clinica Chimica Acta,
451, 97–102. https://doi.org/10.1016/j.cca.2015.01.003
(2) Gill, S. R., Pop, M., DeBoy, R. T., Eckburg, P. B., Turnbaugh, P. J.,
Samuel, B. S., … Nelson, K. E. (2006). Metagenomic analysis of the human distal
gut microbiome. Science, 312(5778), 1355–1359.
(3) Wang, W.-L.,
Xu, S.-Y., Ren, Z.-G., Tao, L., Jiang, J.-W., & Zheng, S.-S. (2015). Application of metagenomics in the human gut
microbiome. World Journal of Gastroenterology, 21(3), 803.
https://doi.org/10.3748/wjg.v21.i3.803
(4) Cénit, M. C., Matzaraki, V., Tigchelaar, E. F., & Zhernakova, A.
(2014). Rapidly expanding knowledge on the role of the gut microbiome in health
and disease. Biochimica et Biophysica Acta (BBA) - Molecular Basis of
Disease, 1842(10), 1981–1992.
https://doi.org/10.1016/j.bbadis.2014.05.023
(5) Shreiner, A. B., Kao, J. Y., & Young, V. B. (2015). The gut
microbiome in health and in disease: Current Opinion in Gastroenterology,
31(1), 69–75. https://doi.org/10.1097/MOG.0000000000000139
(6) Robinson, C. J., Bohannan, B. J. M., & Young, V. B. (2010). From
Structure to Function: the Ecology of Host-Associated Microbial Communities. Microbiology
and Molecular Biology Reviews, 74(3), 453–476. https://doi.org/10.1128/MMBR.00014-10
(7) Bull, M. J.,
& Plummer, N. T. (2014). Part 1: The Human Gut Microbiome in Health and
Disease. Integrative Medicine, 13(6), 17–22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566439/pdf/17-22.pdf
