Diet has a significant effect in the development of dental caries. Yet the role that food plays in systemic inflammation and subsequent tooth loss has not been extensively examined, even though 46% of adults in the United States have periodontitis, reports the Centers for Disease Control and Prevention (CDC).
Using data from the 2009-2010 and 2011-2012 National Health and Nutrition Examination Survey (NHANES), a multi-university research team assessed dietary inflammatory potential using the Dietary Inflammatory Index (DII), a composite measure based on the association between nutrients and systemic pro-inflammatory cytokine levels.
Subjects in the highest quartile of the DII, indicating a pro-inflammatory diet, had lost an average of 0.84 more teeth than those in the lowest quartile of the DII, indicating an anti-inflammatory diet. The researchers concluded that an anti-inflammatory diet could be associated with fewer missing teeth.
Q: Oral inflammation often is attributed to bacterial factors and infection. How does diet fit into its mechanics?
A: We know very well that dental caries are largely attributed to cariogenic dietary habits, with carbohydrate-rich diets being a key modifiable risk factor for disease prevention. The effect that dietary habits have on tooth loss is such that a diet restricting fermentable carbohydrates (eg, simple sugars and complex carbohydrates) can prevent caries. Nonetheless, little information was available on the effect of diet on periodontitis.
Our study focused on the cumulative pro-inflammatory effect of diet. For instance, certain micro- and macronutrients have been shown to elicit an increase in molecules that contribute to an overall pro-inflammatory state (eg, IL-1β, IL-6, and tumor necrosis factor (TNF)-α, among others) that sets up the host for inflammatory diseases such as diabetes, cardiovascular diseases, and periodontitis. Further, specific dietary components such as docosahexaenoic acid (DHA) are associated with a systemic increase in anti-inflammatory molecules that may boost the immune system towards cessation of the inflammatory process in the periodontium.
Q: Specifically, what kinds of foods would comprise anti-inflammatory and pro-inflammatory diets?
A: We used a collective index of dietary inflammatory content, which includes 45 different food parameters (mostly micro- and macronutrients, flavonoids, and some individual food items) to assess the overall effect of diet on periodontal disease status. We hope to further this research line and assess the effect of targeted dietary modifications on periodontal health. An example of an anti-inflammatory diet would include high relative consumption of omega-3 fatty acids, vitamin D, fibers, and green/black tea. Participants were considered to follow a pro-inflammatory diet if their diet was particularly rich in carbohydrates, trans fat, or had overall high caloric intake.
Q: Did you see a relationship between confounders like smoking and obesity with pro-inflammatory diets?
A: There a was a positive association between body mass index and dietary inflammatory profiles as well as smoking and dietary inflammatory profiles. To put this into perspective, in the highest quartile of pro-inflammatory diets, 28% of participants were current smokers as compared to 9% smokers in the quartile with the least pro-inflammatory dietary profiles. Our models adjusted for these important confounders, but often times this may not be enough to control for a strong effect. This is the reason why we have emphasized that further validation of the present findings in non-smoking populations is necessary in prospective studies.
Q: Which demographics or subgroups had the most missing teeth?
A: Our results are consistent with CDC reports and what has been known for a long time that increased age, current smoking, and low educational status are strongly associated to tooth loss.
Q: The results were based on the 2009-2010 and 2011-2012 NHANES studies. Have diets evolved since those surveys? And how do you see these trends evolving?
A: Given that the 2013-2014 NHANES oral examination data was released after this study was submitted, the data included is quite contemporary. The dietary guidelines for Americans have recently changed and the results of this change have not yet been depicted in relevant health metrics, but it is certainly interesting to monitor changes in that regard.
Q: The study suggests the need for a tooth loss agenda in dietary public health interventions. Could you describe how this would work?
A: This is a very important point. Major discussion has taken place over the last decade regarding the association between oral and systemic health, and efforts have been targeted at quantifying the effect. Nevertheless, despite the fact that treatment of periodontitis may improve another chronic inflammatory condition, an equally relevant discussion is whether chronic inflammatory conditions share a common cluster of risk factors. The answer is overwhelmingly yes. The addition of preventive oral health in the agenda for dietary public health interventions to prevent diabetes, obesity, and other inflammatory conditions has the potential to be a very cost-effective preventive strategy.
Q: Would the effect of these strategies extend beyond oral health and into systemic health?
A: I believe so. A plethora of information is available to support that most chronic inflammatory conditions share common risk factors, and looking at these primary risk factors is often a more meaningful strategy than looking into disease associations for diseases that share component causes. For instance, a public health intervention to target smoking, which is a shared risk factor between periodontitis and lung cancer, is more promising than the pursuit of periodontitis as a risk factor for lung cancer.
Q: Finally, what can dentists do to encourage their patients to choose more anti-inflammatory diets?
A: As dentists, we have realized the need to grow our professional skills in alignment with other health professionals, including physicians and nutrition specialists. Inter-disciplinary collaboration among health professionals to improve patient outcomes is definitely the present and not the future.