Smoking cessation induces profound changes in the composition of the intestinal microbiota in humans

PLoS One. 2013;8(3):e59260. doi: 10.1371/journal.pone.0059260. Epub 2013 Mar 14.


Background: The human intestinal microbiota is a crucial factor in the pathogenesis of various diseases, such as metabolic syndrome or inflammatory bowel disease (IBD). Yet, knowledge about the role of environmental factors such as smoking (which is known to influence theses aforementioned disease states) on the complex microbial composition is sparse. We aimed to investigate the role of smoking cessation on intestinal microbial composition in 10 healthy smoking subjects undergoing controlled smoking cessation.

Methods: During the observational period of 9 weeks repetitive stool samples were collected. Based on abundance of 16S rRNA genes bacterial composition was analysed and compared to 10 control subjects (5 continuing smokers and 5 non-smokers) by means of Terminal Restriction Fragment Length Polymorphism analysis and high-throughput sequencing.

Results: Profound shifts in the microbial composition after smoking cessation were observed with an increase of Firmicutes and Actinobacteria and a lower proportion of Bacteroidetes and Proteobacteria on the phylum level. In addition, after smoking cessation there was an increase in microbial diversity.

Conclusions: These results indicate that smoking is an environmental factor modulating the composition of human gut microbiota. The observed changes after smoking cessation revealed to be similar to the previously reported differences in obese compared to lean humans and mice respectively, suggesting a potential pathogenetic link between weight gain and smoking cessation. In addition they give rise to a potential association of smoking status and the course of IBD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Body Weight / physiology
  • Energy Intake / physiology
  • Female
  • Humans
  • Intestines / microbiology*
  • Male
  • Metagenome / physiology*
  • Middle Aged
  • Phylogeny
  • Principal Component Analysis
  • Smoking Cessation*
  • Young Adult

Grants and funding

This research was supported by research grants from the Swiss National Science Foundation to SRV (Grant No 320000-114009/1), to GR (Grant No. 310030-120312) and the Swiss IBD Cohort (Grant No. 3347CO-108792), and by the Zurich Centre for Integrative Human Physiology of the University of Zurich. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.