Distinct Microbial Signatures in Gut: Impact of City Diets in China

In a groundbreaking study published in the journal *Frontiers in Microbiology* on July 23, 2025, researchers from BGI Genomics' Institute of Intelligent Medical Research (IIMR) revealed that the human gut microbiota can accurately reflect whether an individual resides in Wuhan or Shiyan, two cities located 500 kilometers apart in China's Hubei Province, with a remarkable 94% accuracy. This precision is attributed to the distinct dietary habits prevalent in each city, highlighting the intricate relationship between geography, diet, and gut microbiota.

The study, spearheaded by Professor Li Tao of BGI Genomics, aimed to investigate whether microbiota differences could be discerned at a more localized level, specifically between neighboring cities within the same province. Previous research had established that gut microbiota reflects geographic patterns at larger scales, such as continental and provincial levels. However, the significant variation in microbial profiles observed between Wuhan and Shiyan raised questions about the influence of regional diets on gut health.

Using advanced machine learning techniques, the team analyzed microbiota data from participants living in both cities. They employed shotgun metagenomics to identify 649 bacterial species and 515 metabolic pathways present in the participants' gut microbiota. The findings indicated that despite the demographic similarities of the study groups, including age, body mass index (BMI), and smoking status, their intestinal ecosystems diverged significantly, mirroring the dietary preferences and lifestyle choices characteristic of each city.

Wuhan, known for its abundant wetlands, features a diet rich in freshwater fish, lotus root, and leafy greens. Conversely, Shiyan's culinary practices are heavily influenced by its neighbors, favoring wheat-based dishes and spicy flavors. The researchers identified that the predominant bacterial species in Wuhan participants included *Bacteroides stercoris*, while *Prevotella copri* was more prevalent in Shiyan residents. Notably, 63% of the identified bacterial species were unique to each city, thereby shaping distinct microbial signatures associated with their respective diets.

The study employed a random forest classifier to evaluate the practicality of using these microbial signatures for distinguishing between the populations of the two cities. The results demonstrated that the model, which integrated both bacterial species and metabolic pathways, significantly outperformed those that relied solely on one or the other. Among the most influential predictors was *Bacteroides stercoris*, alongside six other metabolic pathways that provided crucial information about the microbiota's functional roles in health.

Furthermore, the research revealed correlations between specific bacterial species and clinical health indicators, suggesting that the same bacterial species can have varying health implications depending on the local microbiota context. For instance, *Bifidobacterium longum* was associated with healthier liver enzyme levels, while *Flavonifractor plautii* showed a link to elevated low-density lipoprotein (LDL) cholesterol in the Wuhan population.

Professor Li emphasized the significance of these findings, stating, "This study challenges the long-standing belief that gut microbiota differences only matter at the scale of continents or provinces. We found that even people living in neighboring cities have distinct microbial patterns." The implications of this research extend beyond academic curiosity; they pave the way for advancements in precision medicine and personalized nutrition strategies that consider geographic and dietary influences.

As health care continues to evolve towards personalized approaches, understanding how local environments shape human biology will be imperative. The study's insights into city-specific microbiota signatures and interaction networks offer promising avenues for tailoring dietary and therapeutic interventions based on individual living conditions.

In summary, this pivotal research underscores the vital role of diet in shaping gut microbiota and its potential implications for health, emphasizing the necessity for localized approaches in nutritional and medical strategies. With ongoing advancements in microbiome research, the prospect of individualized health care based on geographic and dietary influences is becoming increasingly attainable.