BACKGROUND: Zonulin is a signaling protein secreted by enterocytes that can reversibly open tight junctions. Blood zonulin levels are elevated in disorders characterized by increased intestinal permeability. AIMS: The aim of this study is to compare blood zonulin levels and dietary habits between acne vulgaris patients and healthy controls, as well as to investigate the relationship between blood zonulin levels, diet, disease severity, age at onset, and duration in the acne group. Additionally, we aimed to explore the relationship between diet and blood zonulin levels in both groups. PATIENTS/METHODS: Seventy-five patients with acne vulgaris over the age of 18 years and 75 healthy controls were included in the study. Blood zonulin levels in both groups were analyzed using the sandwich ELISA method. Demographic data, habits, and dietary preferences were recorded. RESULTS: In the acne group, the mean blood zonulin level was significantly higher than in the control group (195.54 ± 49.05 ng/mL vs. 158.45 ± 85.07 ng/mL, p = 0.001). Additionally, milk and high glycemic index food consumption were significantly higher in the acne group. CONCLUSIONS: Our results support the hypothesis that increased intestinal permeability may be involved in the pathogenesis of acne vulgaris. Moreover, our study confirms the relationship between diet and acne. Future studies are warranted to elucidate the impact of acne-promoting and acne-preventive foods on the pathogenesis of acne through intestinal permeability.