Around 26 species of bacteria in the human gut microbiota that appear to be linked to obesity and related metabolic complications have been identified by University of Maryland researchers.
These include insulin resistance, high blood sugar levels, increased blood pressure and high cholesterol, known collectively as "the metabolic syndrome," which significantly increases an individual's risk of developing diabetes, cardiovascular disease and stroke.
"We identified 26 species of bacteria that were correlated with obesity and metabolic syndrome traits such as body mass index (BMI), triglycerides, cholesterol, glucose levels and C-reactive protein, a marker for inflammation," said the senior author, Claire M. Fraser, Ph.D., professor of medicine and microbiology and immunology and director of the Institute for Genome Sciences (IGS) at the University of Maryland School of Medicine.
"We can't infer cause and effect, but it's an important step forward that we're starting to identify bacteria that are correlated with clinical parameters, which suggests that the gut microbiota could one day be targeted with medication, diet or lifestyle changes," Dr. Fraser stated.
Dr. Fraser stressed that the research team, led by Margaret L. Zupancic, Ph.D., then a postdoctoral fellow at IGS, also found an apparent link between the gut bacteria and inflammation, which is believed to be a factor in obesity and many other chronic diseases.
The study is the result of an ongoing collaboration between Dr. Fraser and Alan R. Shuldiner, M.D., in connection with the NIH's Human Microbiome Project, which seeks to characterize microbial communities in the body.
The researchers analyzed the bacteria in fecal samples of 310 members of the Old Order Amish community in Lancaster County, Pa., using a process that enables them to identify a marker gene that serves as a bar code for each type of bacteria.
Participants in the study ranged from lean to overweight to obese; some of the obese participants also had features of the metabolic syndrome.
Dr. Fraser noted that additional research, including an interventional study with the Amish, is essential.
"We can look at whether these bacteria change over time in a given individual or in response to diet or medication," she said.
The results of the study have been published online in PLOS ONE, which is published by the Public Library of Science (PLOS).