Recent research led by biologists at Penn State has unveiled how lifestyle choices shape the composition of beneficial bacteria and other microorganisms in the mouth. The international team discovered that the oral microbiome varies significantly based on subsistence strategies, with factors like smoking influencing its diversity.
Published in the journal Microbiome, the study emphasizes the crucial role of a healthy oral microbiome in digestion, immune support, and protection against pathogens. In contrast, an unhealthy oral microbiome has been linked to various human diseases.
Emily Davenport, assistant professor of biology at Penn State and lead researcher, stated, “The oral microbiome is still underexplored, and most studies have focused on Western populations. By examining how oral microbiome diversity varies with lifestyle globally, we can enhance our understanding of its impact on human health.”
The research involved 63 individuals from Nepal, representing diverse dietary practices. The team investigated how major lifestyle factors, such as subsistence strategies and specific behaviors like smoking, contribute to microbiome differences across populations.
Erica Ryu, a graduate student at Penn State and lead author of the paper, noted, “We know from previous research that there are differences in microbiomes between individuals in highly industrialized societies and those who are nomadic hunter-gatherers, but there exists a broad spectrum of lifestyles in between.”
The researchers analyzed the oral microbiomes of groups with varying subsistence strategies, including foragers, subsistence farmers, and industrialists. They also collected data on lifestyle factors such as diet and medical practices.
Using DNA sequencing of microbial samples from saliva, the team identified specific bacterial species within each individual's oral microbiome. They found that the composition of these species followed a gradient of subsistence strategies, indicating that lifestyle significantly influences the oral microbiome.
Additionally, certain microbial species were associated with specific lifestyle factors, including smoking and the primary grains in individuals' diets. The researchers highlighted previous studies linking consistent smoking habits to oral microbiome composition, suggesting that smoking plays a crucial role in shaping the oral microbiome across different lifestyles.
Davenport remarked, “It makes sense that different microbes might consume different grains in a person's diet, but it's also interesting that we observed a connection with nettles, a fibrous plant often chewed by foragers in this study.”
The findings underscore the importance of incorporating lifestyle factors into future microbiome studies and including diverse global populations. “Studying the population in Nepal offered a unique opportunity to explore lifestyle effects while controlling for various factors like geography that often obscure these effects,” Davenport explained. “This also highlights the impact of lifestyle factors that may play a role in other populations.”
As lifestyles change—whether through diet, relocation, or cultural shifts—so too can the microbiome. Understanding the extent and speed of these changes is vital. “Continued investigation into oral microbiome variation worldwide will enhance our understanding of what truly shapes the microbiome and how it affects human health,” Davenport added.
The research team included Meera Gupta, Yoshina Gautam, Ahmed Shibl, and others from various institutions, supported by funding from the National Institutes of Health and other organizations.