Food Coloring Additives and Incidence of Type 2 Diabetes in the NutriNet-Santé Prospective Cohort

OBJECTIVE: To investigate potential association between exposure to food coloring additives and type 2 diabetes incidence. RESEARCH DESIGN AND METHODS: The study followed 108,723 participants (79.2% female, mean age 42.5 SD 14.6 years) from the French NutriNet-Santé cohort (2009-2023). Dietary data were assessed using repeated 24-h dietary records, including industrial food brands. Cumulative time-dependent exposure to food additives was evaluated through multiple composition databases and ad hoc laboratory assays in food matrices. Associations between exposures to food coloring additives (sex-specific tertiles if proportion of exposed participants was more than two-thirds, or nonexposed/lower/higher exposed based on sex-specific median otherwise) and type 2 diabetes incidence were assessed using multivariable Cox proportional hazards models. RESULTS: There were 1,131 incident type 2 diabetes cases diagnosed (median follow-up, 8.05 years). After false discovery rate correction, intakes of the following colors were associated with higher type 2 diabetes incidence: total food coloring additives (hazard ratio HRhigher vs. non/lower consumers 1.38 95% CI 1.17-1.63, P = 0.0002), total caramel (1.43 1.21-1.67, P = 0.0002), plain caramel (1.46 1.26-1.70, P = 0.0002), sulfite ammonia caramel (1.30 1.07-1.59, P = 0.007), total carotene (1.27 1.08-1.48, P = 0.007), carotenoids (1.39 1.19-1.62, P = 0.0002), β-carotene (1.44 1.23-1.68, P = 0.0002), paprika-capsanthin-capsorubin (1.26 1.08-1.46, P = 0.004), lutein (1.20 1.02-1.40, P = 0.0002), curcumin (1.49 1.29-1.73, P = 0.0002), cochineal-carminic acid-carmines (1.27 1.10-1.48, P = 0.003), and anthocyanins (1.40 1.17-1.68, P = 0.0002). CONCLUSIONS: Several positive associations were observed between exposure to natural and synthetic food coloring additives and type 2 diabetes incidence. Further studies are needed to gain insights into underlying mechanisms, and if confirmed, call for reevaluation of food coloring additives to protect consumer health.