The Amish were identified as an ideal subject population because close genetic relationships, similar lifestyles, and low prescription drug usage, explained researchers from the Institute for Genome Sciences at the University of Maryland School of Medicine.
The data, published in PLoS ONE, indicated that some specific species, but not full gut communities, were associated either positively or negatively with metabolic syndrome traits.
"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," said lead researcher Claire Fraser.
Metabolic syndrome (MetS) is a condition characterised by central obesity, hypertension, and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type-2 diabetes and cardiovascular disease (CVD).
Fifteen per cent of adult Europeans are estimated to be affected by MetS, while the US statistic is estimated to be a whopping 32 percent. Obesity is established to be the main risk factor for MetS.
The study adds to emerging body of science supporting the effects of gut microflora on metabolic factors and obesity.
In 2006, Jeffrey Gordon and his group at Washington University in St. Louis reported in Nature (Vol. 444, pp. 1022-1023, 1027-1031) that microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person, suggesting that obesity may have a microbial component.
Dr Gordon and his group recently pushed back the scientific boundaries even further in this area. In an ‘elegant’ study, the St Louis-based scientists reported that probiotics in a yogurt did not colonize the gut microflora when studied in identical twins, but additional study in mice revealed that ingestion of probiotic bacteria produced a change in many metabolic pathways, particularly those related to carbohydrate metabolism (Science Translational Medicine, Vol. 3, 106ra106).
According to the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host".
The Maryland-based researchers characterized the gut microbiota in 310 Amish subjects. Data revealed the presence of three communities of interacting bacteria in the gut.
While no specific group was related to body mass index (BMI) or any metabolic syndrome trait, further analysis revealed that twenty-two bacterial species and four operational taxonomic units (OTUs) related to metabolic syndrome traits, said the researchers.
“Approximately half of these species are members of the core gut microbiota in the Amish and members of the Bacteroidetes and Firmicutes phyla,” they added.
“Follow-on longitudinal studies can begin to address whether specific gut bacterial taxa a play a causal role in the predisposition to or development of the metabolic syndrome, as well as the utility of interventions that modulate the composition of the gut microbiota to mitigate the risk of cardiovascular complications associated with metabolic syndrome.”
Source: PLoS ONE
7(8): e43052. doi:10.1371/journal.pone.0043052
“Analysis of the Gut Microbiota in the Old Order Amish and Its Relation to the Metabolic Syndrome”
Authors: M.L. Zupancic, B.L. Cantarel, Z. Liu, E.F. Drabek, K.A. Ryan, et al.