**6. Conclusions**

The human body is a super-organism consisting of 10 times more microbial cells than our own body cells. The body's assortment of microorganisms is mainly in gastrointestinal tract, collectively called the gut microbiota. It can be comparable to an organ in because it performs functions necessary for our survival by contributing directly and/or indirectly in various physiological processes. For the

**187**

**Author details**

Haseeb Anwar1

Humaira Muzaffar1

Faisalabad, Pakistan

University, Multan, Pakistan

provided the original work is properly cited.

Muhammad Irfan Ullah3

\*, Shahzad Irfan1

, Imtiaz Mustafa1

\*Address all correspondence to: drhaseebanwar@gcuf.edu.pk

, Ghulam Hussain1

1 Department of Physiology, Government College University, Faisalabad, Pakistan

2 Institute of Pharmacy, Physiology and Pharmacology, University of Agriculture,

3 Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Imran Mukhtar1

, Muhammad Naeem Faisal2

and

, Saima Malik1

,

*Gut Microbiome: A New Organ System in Body DOI: http://dx.doi.org/10.5772/intechopen.89634*

effecting disease progression needs further investigations.

past decade, human gut microbiota has been extensively studied as many scientists believe that human health mainly depends on microbes that are living on or in our body apart from our own genome. Recently, research findings have suggested that gut microbiome is evolving as a new organ system mainly due to its specific biochemical interaction with its host which affirm its systemic integration into the host physiology as gut bacteria are not only critical for regulating gut metabolism, but also important for other systems of host including immune system. The focus of this chapter was to highlight the importance of gut microorganisms as a new organ system and their possible involvement with host systems as well as the metabolism of different drugs and nutrients in the gut by these microbes. So, in this chapter, we have reviewed opinions of different researchers about the role of gut microbiota in maintaining health as well as its contributory role in different ailments. However, literature revealed that the involvement of gut microbiota in altering host genetics

#### *Gut Microbiome: A New Organ System in Body DOI: http://dx.doi.org/10.5772/intechopen.89634*

*Parasitology and Microbiology Research*

more serious and long-lasting consequences have been suggested. For example, it was reported that at the end of a 5-day treatment with the antibiotic ciprofloxacin, most of the gut bacteria was restored to the pre-treatment levels in 4 weeks, but some intestinal bacteria failed to recover even after 6-months. Moreover, a 7-day treatment with clindamycin, a drug of choice for treatment of *Bacteroides* infec-

Food is metabolized by the gut microbial species to extract nutrients, but some microbial species are more efficient in extracting nutrients from food as compared to other species. As different individuals have slightly different microbial populations, it is probable that more nutrients are harvested by some people's gut microbes making them perhaps more prone to become overweight. A high percentage of *Firmicutes* was found in the gut microbiome of genetically obese mice while a high percentage of *Bacteriodetes* were observed in lean mice. Similar observation was reported in lean and obese human volunteers. Moreover, it was also seen that the obese people who used a low-caloric diet to lose weight, their gut microbiota shifted

The human body is a super-organism consisting of 10 times more microbial cells than our own body cells. The body's assortment of microorganisms is mainly in gastrointestinal tract, collectively called the gut microbiota. It can be comparable to an organ in because it performs functions necessary for our survival by contributing directly and/or indirectly in various physiological processes. For the

tions, resulted in disrupted gut microbiome for up to 2 years [125].

to a similar bacterial population as observed in lean people [125].

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**5.3 Diet and obesity**

*Environmental factors influencing gut microbiota.*

**Figure 2.**

**6. Conclusions**

past decade, human gut microbiota has been extensively studied as many scientists believe that human health mainly depends on microbes that are living on or in our body apart from our own genome. Recently, research findings have suggested that gut microbiome is evolving as a new organ system mainly due to its specific biochemical interaction with its host which affirm its systemic integration into the host physiology as gut bacteria are not only critical for regulating gut metabolism, but also important for other systems of host including immune system. The focus of this chapter was to highlight the importance of gut microorganisms as a new organ system and their possible involvement with host systems as well as the metabolism of different drugs and nutrients in the gut by these microbes. So, in this chapter, we have reviewed opinions of different researchers about the role of gut microbiota in maintaining health as well as its contributory role in different ailments. However, literature revealed that the involvement of gut microbiota in altering host genetics effecting disease progression needs further investigations.
