The Association of Dietary Polyphenol Intake with the Risk of Type 2 Diabetes: Tehran Lipid and Glucose Study

PURPOSE: The current study aimed to investigate the relationship between daily consumption of total polyphenol and its subclasses and the incidence of diabetes. MATERIALS AND METHODS: Eligible adults (n=6,547) were chosen from among participants of the Tehran Lipid and Glucose Study (TLGS) with an average follow-up of 3.0±1.6 years. Dietary intakes were evaluated using a valid and reliable semi-quantitative food frequency questionnaire. Biochemical variables and anthropometrics were evaluated at baseline and follow-up examinations. Multivariate Cox proportional hazard regression models were used to estimate the development of type 2 diabetes mellitus (T2DM) in relation to total intake of polyphenol and its subclasses (flavonoids, phenolic acids, stilbenes, and lignans). RESULTS: This study was conducted on 2,882 men and 3,665 women, aged 41.3±14.6 and 39.0±13.4 years, respectively. The number of participants with the new-onset T2DM was 253. Mean intake of total polyphenol was 346±245 mg/1000 kcal. Risk of type 2 diabetes decreased from quartiles 1 to 4 for total polyphenols (HR: 1.00, 0.37, 0.61, 0.50, P(trend)<0.01), phenolic acids (HR: 1.00, 0.57, 0.49, 0.45, P(trend)<0.01), and lignans (HR: 1.00, 0.67, 0.61, 0.60, P(trend)<0.01), whereas non-significant results were found for flavonoids and stilbenes. This study suggests an inverse association between total intake of polyphenols, phenolic acids, and lignin, and the risk of T2DM. CONCLUSION: These results emphasize the potential protective role of polyphenol rich food groups (especially fruits and vegetables) in the prevention of T2DM.