Association between dietary insulin index and risk of depression, anxiety, and sleep disturbance in a group of Iranian physically active adults

Objectives Anxiety and depression are among the most prevalent mental health disorders worldwide (In Iran, approximately 21% of adults). Athletes often consume carbohydrate-rich diets to boost their performance, but this diet might potentially influenced mood through insulin secretion and increases in serotonin and melatonin. This study investigates association between the Dietary Insulin Index (DII) and risk of depression, anxiety, and sleep disorders among physically active adults. Methods This cross-sectional study included 690 bodybuilding athletes (ages 18–50, BMI 20–30) from Kashan, Iran. Demographic, medical, and mental health data of participants were collected using the Beck Depression Inventory II (BDI-II), Beck Anxiety Inventory (BAI), and Pittsburgh Sleep Quality Index (PSQI). Dietary intake was assessed via a 147-item Food Frequency Questionnaire. The DII and Dietary Insulin Load (DIL) were calculated by multiplying the insulin index of each food item by its energy content and consumption frequency, and summing across all items. Results In the fully adjusted model, there was no significant association between DII and the odds of depression (OR: 0.80; 95% CI: 0.48, 1.33) or anxiety (OR: 1.14; 95% CI: 0.61, 2.12). However, individuals in the highest tertile of DII had higher risk of sleep disorders as compared to those at the lowest tertile (OR: 1.51; 95% CI: 1.04, 2.22; p for trend = 0.03). Conclusions A significant direct association was found between DII and odds of sleep disorders, but no with the risk of anxiety or depression. Further studies are needed to explore these findings among athletes with various physical activity levels.