A city’s sewage system may hold clues about the gut bacteria of urban populations, and, in turn, understanding the microorganisms that make up the human intestines can provide clues about obesity rates. The link between obesity and the gut microbiome (the totality of microorganisms and their genetic interactions) and weight gain is currently a key topic within clinical microbiology. Several areas of research, including some reported on Digital Journal, suggest that there is a strong correlation, perhaps even causation.
With the new research, not all the bacteria found in sewage are also found in the human gastrointestinal system. However, DNA sequencing has revealed similarities in the abundance of known gut bacteria that correlate with health issues like obesity.
With the study,researchers collected samples from sewage treatment plants in 71 different U.S. cities with varying obesity rates. These included Steamboat Springs, Colorado, with an obesity rate of 13.5 percent to St. Joseph, Missouri, with a rate of 37.4 percent. Specific bacteria, such as Bacteroidaceae, were found in greater abundance in the locales with the relatively high obesity rates.
A review of the data found that the correlation with such bacteria was able to predict whether a city was lean or obese with 80- to 90-percent accuracy. Monitoring a city’s sewage microbiome could become a useful long-term surveillance approach for the assessment of obesity, based on the research findings.
The lead researcher, Sandra McLellan at the University of Wisconsin-Milwaukee, told Inside Science: “With a random sampling of a million people, we can start to look for trends in how human populations might be different in their microbiomes, according to their demographics.”
The new research has been published in the journal mBio, in a paper called “Sewage Reflects the Microbiomes of Human Populations.”