The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome
Gastric acidity is likely a key factor shaping the diversity and composition of microbial communities found in the vertebrate gut. We conducted a systematic review to test the hypothesis that a key role of the vertebrate stomach is to maintain the gut microbial community by filtering out novel micro...
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Published in | PloS one Vol. 10; no. 7; p. e0134116 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
29.07.2015
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | Gastric acidity is likely a key factor shaping the diversity and composition of microbial communities found in the vertebrate gut. We conducted a systematic review to test the hypothesis that a key role of the vertebrate stomach is to maintain the gut microbial community by filtering out novel microbial taxa before they pass into the intestines. We propose that species feeding either on carrion or on organisms that are close phylogenetic relatives should require the most restrictive filter (measured as high stomach acidity) as protection from foreign microbes. Conversely, species feeding on a lower trophic level or on food that is distantly related to them (e.g. herbivores) should require the least restrictive filter, as the risk of pathogen exposure is lower. Comparisons of stomach acidity across trophic groups in mammal and bird taxa show that scavengers and carnivores have significantly higher stomach acidities compared to herbivores or carnivores feeding on phylogenetically distant prey such as insects or fish. In addition, we find when stomach acidity varies within species either naturally (with age) or in treatments such as bariatric surgery, the effects on gut bacterial pathogens and communities are in line with our hypothesis that the stomach acts as an ecological filter. Together these results highlight the importance of including measurements of gastric pH when investigating gut microbial dynamics within and across species. |
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Bibliography: | SourceType-Scholarly Journals-1 ObjectType-Feature-4 ObjectType-Undefined-1 content type line 23 ObjectType-Review-2 ObjectType-Article-3 Competing Interests: The authors have declared that no competing interests exist. Conceived and designed the experiments: NF RRD. Performed the experiments: DEB AMK. Analyzed the data: DEB. Contributed reagents/materials/analysis tools: DEB AMK JEL NF RRD. Wrote the paper: DEB AMK JEL NF RRD. |
ISSN: | 1932-6203 1932-6203 |
DOI: | 10.1371/journal.pone.0134116 |