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A review of the relationship between the gut microbiota and amino acid metabolism

DOI:10.1007/s00726-017-2493-3
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Rui Lin
Rui Lin
Rui Lin
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Wentian Liu
Wentian Liu
Wentian Liu
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Meiyu Piao
Meiyu Piao
Meiyu Piao
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Hong Zhu
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Hong Zhu
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Abstract and Figures

New evidence has emerged in recent years to suggest a strong link between the human gut microbiota, its metabolites, and various physiological aspects of hosts along with important pathophysiological dimensions of diseases. The research indicates that the gut microbiota can facilitate metabolite production in two ways: first, the resident species of the gut microbiota use the amino acids produced from food or the host as elements for protein synthesis, and second, conversion or fermentation are used to drive nutrient metabolism. Additionally, the gut microbiota can synthesize several nutritionally essential amino acids de novo, which is a potential regulatory factor in amino acid homeostasis. The primary objective of this review is to summarize the current literature relating to the ways in which microbial amino acids contribute to host amino acid homeostasis.
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Amino Acids (2017) 49:2083–2090
DOI 10.1007/s00726-017-2493-3
REVIEW ARTICLE
A review oftherelationship betweenthegut microbiota
andamino acid metabolism
RuiLin1 · WentianLiu1· MeiyuPiao1· HongZhu2
Received: 4 July 2017 / Accepted: 11 September 2017 / Published online: 20 September 2017
© Springer-Verlag GmbH Austria 2017
qualitative transformations associated with several metabo-
lites generated by the gut microbiota are implicated in the
pathophysiological dimensions of illnesses such as meta-
bolic syndrome, inflammatory bowel disease, diabetes mel-
litus (types 1 and 2), asthma, colon cancer, obesity, major
depression, and autism (Diaz Heijtz etal. 2011; Vijay-Kumar
etal. 2010; Uronis etal. 2009; De Filippo etal. 2010).
A fundamental function of the gut microbiota that has
long been understood by the research community is the
metabolism of indigestible matter consumed by the host,
thereby contributing to optimal energy production. In this
context, as a prominent part of the human diet, amino acids
play a crucial role not simply by serving as the basic ele-
ments of proteins and peptides, but more importantly in driv-
ing the production of numerous bioactive molecules that
contribute to the maintenance of signaling pathways and
metabolism (Sato etal. 2006; Wu 2013; Wu etal. 2014).
Researchers have compared germ-free mice and convention-
alized mice and found that the latter possessed an altered
distribution of free amino acids in the gastrointestinal (GI)
tract, importantly indicating that the resident species of the
gut microbiota are crucial to host amino acid homeostasis
and health (Mardinoglu etal. 2015). The purpose of the
present review is to outline how host nutritional status and
physiological health are prominently influenced by amino
acid metabolism in the gut microbiota.
Microbial amino acid metabolism
Gut microbiota andtheregulation ofamino acid
catabolism andutilization
The gut microbiota performs a crucial function in facilitat-
ing the regulation of the amino acid pool and profile over
Abstract New evidence has emerged in recent years to
suggest a strong link between the human gut microbiota, its
metabolites, and various physiological aspects of hosts along
with important pathophysiological dimensions of diseases.
The research indicates that the gut microbiota can facilitate
metabolite production in two ways: first, the resident spe-
cies of the gut microbiota use the amino acids produced
from food or the host as elements for protein synthesis, and
second, conversion or fermentation are used to drive nutrient
metabolism. Additionally, the gut microbiota can synthesize
several nutritionally essential amino acids de novo, which is
a potential regulatory factor in amino acid homeostasis. The
primary objective of this review is to summarize the cur-
rent literature relating to the ways in which microbial amino
acids contribute to host amino acid homeostasis.
Keywords Amino acids· Gut microbiota· Dietary·
Tryptophan· Obesity· Type 2 diabetes mellitus
Introduction
Host homeostasis with respect to issues of physiology and
metabolism is crucially underpinned by the gut microbiota
and its metabolites (Human Microbiome Project C 2012).
Recent literature indicates that various quantitative and
Handling Editors: C.-A. A. Hu, Y. Yin, Y. Hou, G. Wu, Y. Teng.
* Rui Lin
pubmed1128@126.com
1 Department ofGastroenterology andHepatology, Tianjin
Medical University, General Hospital, Tianjin300052, China
2 Department ofColorectal Surgery, Nankai University
Affiliated Hospital, Tianjin801225, China
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Therefore, the decreased fecal levels of alanine, threonine, aspartate, lysine and glycine could reflect the improved inflammatory status in vivo. In addition, threonine and lysine in the intestine can synthesize butyrate, thus improving the lipid and blood pressure levels (51). ...
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