An international research team led by Penn State biologists has discovered that lifestyle choices significantly shape the oral microbiome. The study examined various subsistence strategies in Nepal, from nomadic foragers to industrialized groups, revealing how factors like diet and smoking influence oral bacteria.
Recent research spearheaded by Penn State biologists demonstrates that our lifestyle choices directly influence the beneficial bacteria and microorganisms in our mouths. The international study, which analyzed saliva samples from various Nepali populations, underscores how the “oral microbiome” reflects different subsistence strategies — ranging from nomadic hunter-gatherers to industrialized groups.
The study, published in the journal Microbiome, reveals groundbreaking insights into how lifestyle factors, such as diet and smoking, shape the microscopic inhabitants of our mouths. Emily Davenport, assistant professor of biology at Penn State and the leading researcher, explained the study’s significance.
“The oral microbiome has been understudied, and most studies of the oral microbiome have been conducted in Western populations. Although we have learned a lot from that, microbiomes look different around the world,” Davenport said in a news release. “By studying how the diversity and composition of the oral microbiome varies with lifestyle in a global context, we can improve our knowledge of how the oral microbiome impacts human health.”
The research team collected saliva samples from 63 Nepali individuals belonging to diverse subsistence strategies, including foragers, recently settled subsistence farmers, traditional agriculturalists and both local and expatriate industrialists. This comprehensive approach was aimed at isolating the impact of lifestyle on oral microbiomes while controlling for geographical variables.
“We know from previous studies that there are differences in the microbiome between individuals that live in highly industrialized, Westernized societies and those that are nomadic hunter gatherers, but there is a broad spectrum of lifestyles between those,” first author Erica Ryu, a graduate student in biology at Penn State, said in the news release. “Our understanding of these relationships so far has been clouded by geography; it’s difficult to make statements about the impact of lifestyles when you are comparing people in different countries with, for example, different climates, access to medical care and exposure to diseases. In this study, we comprehensively investigated the oral microbiome of individuals across a range of lifestyles from the same country, Nepal.”
Using DNA sequencing of the microbes found in saliva, the researchers identified varying bacterial species compositions that align with the gradient of subsistence strategies. For instance, certain bacterial strains were more prevalent among foragers, while others were dominant in industrialists.
The study also identified specific lifestyle factors — such as smoking and dietary staples — that correlate with these microbial variations.
“It makes sense that different microbes might feed on the different grains in a person’s diet, but it’s interesting that we also see an association with sisnu, also called nettle,” added Davenport. “Nettle is a fibrous plant often chewed by the foragers in this study, much like people might chew gum. Given its important role in Nepali cuisine, culture and medicine, it’s interesting to see it is associated with oral microbes.”
The findings suggest that smoking’s impact on the oral microbiome is consistent across different populations, aligning with previous research in industrialized societies. These insights enhance our understanding of how lifestyle choices affect human health globally.
Davenport and her team stress the importance of incorporating a wide range of lifestyle factors in future microbiome studies while expanding research to include diverse global populations.
“Whenever you make a shift — whether it’s to a different diet or different location or different culture — the microbiome can change too, and it’s important to understand to what extent and how quickly these changes occur,” Davenport added.