What is already known
The composition of the human microbiota, which plays a crucial role in health and disease, is influenced by factors such as genetics, ethnicity and diet, which can vary by geographic region.
What this research adds
Researchers analyzed more than 168,000 gut microbiota samples from people in 68 countries and confirmed that variation in microbiota composition is influenced by genetics, diet and antibiotics use. High-income countries are overrepresented in existing datasets, while regions like Eastern Asia are underrepresented. Technical factors such as sample collection methods, DNA extraction and sequencing approaches also impact the availability of diverse microbiota data.
Conclusions
The findings highlight the need for more diverse microbiota research across the globe.
The composition of the human microbiota, which plays a crucial role in health and disease, is influenced by factors such as genetics, ethnicity and diet, which can vary by geographic region. A new database of thousands of gut microbiota samples from across the word highlights the need for more diverse microbiota research across the globe.
This resource, published in Cell, may help researchers identify global patterns and knowledge gaps in microbiota research.
Differences in microbiota composition have been observed between healthy people and those with conditions such as colorectal cancer and inflammatory bowel disease. However, not all populations are equally represented in microbiota studies, making it hard to draw generalizable conclusions.
To create a more complete picture of the human microbiota, Richard Abdill at the University of Chicago in Illinois and his colleagues created a database, called the Human Microbiome Compendium, that contains more than 168,000 gut microbiota samples from people in 68 countries.
Underrepresented populations
Most of the microbiota samples available come from Europe and North America, whereas regions such as Latin America, the Caribbean and Sub-Saharan Africa are underrepresented in microbiota research. Microbiotas from underrepresented regions show much higher microbial diversity, with many taxa still undiscovered.
Geographic differences were especially important when it came to the number of unique microbial taxa found in the samples. For example, Eastern and South-Eastern Asia had the highest number of unique taxa, while regions such as Latin America and Sub-Saharan Africa had fewer taxa. Specific microbial groups, including Bacteroides and Prevotella, varied from one region to another.
Most microbiota studies rely on a type of sequencing that is commonly used to identify microorganisms, but there is regional and technical variation in the data, which could affect the results, the researchers found.
Distinguishing microbiotas
Using machine learning techniques, the team developed an approach to distinguish between microbiotas from different regions. However, the accuracy of this approach varied by region.
For example, microbiotas from Australia/New Zealand and Eastern/South-Eastern Asia were easily distinguishable. However, it was more difficult to distinguish microbiomes from Europe and Northern America from those of Latin America and the Caribbean, pointing to the need for further research to understand these complex patterns.
The findings highlight global variations in the human gut microbiota, revealing that certain regions likely carry many undiscovered microbial species due to limited sampling, the authors say. “We expect this compendium will be a valuable resource for the community and enable expanded insights into the microbial ecology of the human gut.”
