A UB study involving 1,175 postmenopausal women is the first to investigate the connection between diet quality and the oral microbiome.

The study found that while overall HEI-2020 scores were linked to the composition of the oral microbiome they were not associated with its diversity However, individual components of the HEI-2020 such as specific food groups were linked to both the diversity and composition of oral bacteria. This indicates that certain dietary elements may have a greater influence on the oral microbiome than overall diet quality alone. For instance higher intake of vegetables and total protein foods was associated with a more diverse oral microbiome which is generally considered beneficial. In contrast greater consumption of dairy and added sugars was linked to reduced microbial diversity which may negatively impact oral and overall health.

Previous studies have largely focused on how individual nutrients or foods affect the oral microbiome explains lead author Yihua Yue who conducted the research while earning her PhD in epidemiology at UB’s School of Public Health and Health Professions. But in reality people consume foods in combination and these interactions can influence health outcomes in more complex ways.

That’s why we chose to focus on overall diet quality to provide a more holistic view of dietary intake says Yue now a postdoctoral research fellow at the Cleveland Clinic. Our goal was to examine how diet quality as measured by the Healthy Eating Index correlates with the types of bacteria found in the oral cavity. Specifically we wanted to determine whether the diversity and composition of the oral microbiome differ between individuals with high- versus low-quality diets.

Amy Millen the study’s corresponding author and an associate professor in UB’s Department of Epidemiology and Environmental Health adds that prior research has linked periodontal disease to a higher risk of several chronic conditions including cancer cardiovascular disease and inflammation-related diseases like age-related macular degeneration.

What we do know Millen explains is that nutrition is a known risk factor for many diseases rooted in inflammation. Our research has focused on determining whether nutrition both specific nutrients and overall dietary patterns also contributes to the risk of developing periodontal disease. Since oral bacteria are known to play a direct role in the onset of periodontal disease we hypothesized that finding links between diet quality and the oral microbiome could offer further evidence supporting the role of diet in oral and potentially systemic health including outcomes like dental caries.

The Healthy Eating Index 2020 (HEI-2020) comprises 13 components that reflect various dimensions of diet quality. While higher scores for individual components are generally seen as beneficial to overall health Yue cautions that this doesn’t necessarily mean all components affect the oral microbiome in the same way.

Our findings indicate that specific dietary recommendations from the Dietary Guidelines for Americans especially those related to sugar intake vegetables and seafood and plant-based protein may influence the composition of the oral microbiome says Yue. These insights could support the U.S. Department of Agriculture in considering the potential relevance of the HEI-2020 for oral health outcomes.

Although the study focused exclusively on postmenopausal women the authors emphasize the importance of this demographic as they face a higher risk of gum disease and tooth loss due to aging and hormonal shifts. They recommend that future research expand to more diverse populations with varying dietary patterns and lifestyle factors to build on these findings.

Source: https://www.buffalo.edu/news/news-releases.host.html/content/shared/university/news/ub-reporter-articles/stories/2025/04/diet-quality-oral-microbiome.detail.html