Food processing and its association with dental caries: Data from NHANES 2011-2014

Objective: To assess whether proportional contribution of unprocessed or minimally processed, processed or ultra-processed foods to daily energy intake is associated with dental caries in US adults. Methods: This secondary cross-sectional analysis included adults aged 20 to 59 years old with complete oral examinations, using data gathered from cycles 2011-2012 and 2013-2014 of the continuous National Health and Nutrition Examination Survey (NHANES). Dietary recall data were categorized according to the NOVA classification into four groups: unprocessed or minimally processed foods (Group 1), processed culinary ingredients (Group 2), processed foods (Group 3) and ultra-processed foods (Group 4). The proportional contribution of each of these groups to mean daily energy intake was calculated and then cut into quartiles (Group 1, Group 3 and Group 4) or tertiles (Group 2). Two separate measures were used to assess dental caries: the decayed, missing, filled teeth (DMFT) index and, after exclusion of edentulous participants, prevalence of untreated caries. Poisson regression was used to model DMFT, while logistic regression was used to model the prevalence of untreated dental caries. Models were calculated for each NOVA group. All models were controlled for age, gender, race/ethnicity, level of education, income, access to oral health services, body mass index, smoking status and total energy intake. Analyses took into account NHANES sampling weights. Results: We analysed data from 5720 individuals, of whom 123 (2.2%) were edentulous. Mean DMFT was 9.7 (± 0.2), while the prevalence of untreated dental caries was 26.0%. Mean daily energy intake was 2170 kcal (± 17). Mean contribution to overall daily energy intake was 28.6% (± 0.5) for G1 foods, 4.3% (± 0.1) for G2 foods, 10.1% (± 0.2) for G3 foods and 56.9% (± 0.5) for G4 foods. A higher intake of G3 was associated with lower DMFT at the fourth quartile (0.89; 95%: CI 0.81-0.96), while a higher intake of G4 was associated with a higher DMFT at the fourth quartile (1.10; 95% CI: 1.04-1.16). In the adjusted models for untreated dental caries, no statistically significant associations were found with any of the NOVA groups. Conclusion: Higher proportional intake of NOVA groups is only weakly associated with dental caries. Widespread exposure to a highly ultra-processed diet may explain these weak associations.