Prediyabetli ve Tip 2 Diyabetli Bireylerde Diyet Polifenol Alım Düzeyleri ve Diyetin İnflamatuar İndeksinin Değerlendirilmesi

Abstract

Yıldırım Pınar S., Evaluation of Dietary Polyphenol Intake Levels and Dietary Inflammatory Index in Individuals with Prediabetes and Type 2 Diabetes, Hacettepe University Gradute School of Health Sciences Department of Food Service Systems Master’s Thesis, Ankara, 2026. The protective effects of a polyphenol-rich diet in the prevention and management of diabetes have been gaining increasing importance. Accordingly, this study was conducted on a total of 150 adult individuals (50 healthy controls, 50 individuals with prediabetes, and 50 individuals with type 2 diabetes) with the aim of evaluating dietary polyphenol intake levels and the Dietary Inflammatory Index (DII) in healthy individuals, individuals with prediabetes, and individuals with type 2 diabetes. Participants' sociodemographic characteristics, dietary habits, and physical activity levels were assessed using a questionnaire, while anthropometric measurements were obtained and biochemical parameters were recorded. Participants' dietary polyphenol intake was determined using the Polyphenol Consumption Frequency Questionnaire, and DII scores were calculated from 24-hour dietary records. A significant difference was found among the groups in terms of total polyphenol intake, with the control group having higher polyphenol intake than the prediabetes and type 2 diabetes groups (p<0.001). Similarly, a significant difference was found among the groups in terms of flavonoid intake, and the control group had higher flavonoid intake than the type 2 diabetes group (p=0.028). No statistically significant difference was found between sexes in terms of polyphenol intake levels (p>0.05). The DII scores of the prediabetes group were found to be higher than those of the control group (p=0.029). When the relationships between polyphenol intake and anthropometric measurements were examined, significant negative correlations were identified between total polyphenol intake and BMI (r=-0.208; p=0.011), body weight (r=-0.170; p=0.038), and waist-to-hip ratio (r=-0.232; p=0.040). Negative correlations were also found between flavonoid and stilbene intake and BMI (p<0.05). According to the evaluation based on total polyphenol intake tertiles, individuals in the highest polyphenol intake tertile were found to have significantly lower waist-to-hip ratios (p=0.013). When the biochemical findings were evaluated, negative correlations were found between total polyphenol intake and fasting blood glucose (r=-0.345; p<0.01), HbA1c (r=-0.111; p=0.001), and triglyceride levels (r=-0.143; p=0.048). Negative correlations were also identified between phenolic acid, flavonoid, stilbene, and lignan intake and fasting blood glucose (p<0.05). A positive correlation was found between HDL cholesterol levels and flavonoid intake (r=0.189; p=0.021). According to the evaluation based on total polyphenol intake tertiles, individuals in the highest polyphenol intake tertile were found to have lower fasting blood glucose levels and higher HDL cholesterol levels (p<0.05). A significant negative correlation was found between total polyphenol intake and DII (p=0.030), indicating that higher polyphenol consumption was associated with diets having lower inflammatory potential. Consequently, higher polyphenol consumption was associated with better glycemic control, higher HDL cholesterol levels, lower indicators of abdominal obesity, and lower dietary inflammatory scores. The findings obtained indicate that a polyphenol-rich diet may provide potential benefits in the prevention and management of prediabetes and type 2 diabetes.