This study investigates the association between the composite dietary antioxidant index (CDAI) and the prevalence of stroke in the U.S. population using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. The CDAI is a measure of antioxidant intake derived from various dietary sources, including vitamins, minerals, and phytochemicals. The study found that higher CDAI scores were associated with a lower risk of stroke, with an odds ratio (OR) of 0.96 (95% CI: 0.94-0.98) after adjusting for confounding variables. The association was nonlinear, with a significant decrease in stroke risk up to a certain threshold, after which the protective effect stabilized. Subgroup analyses showed that the association was consistent across different populations, including gender, age, race, and BMI categories. A predictive nomogram model based on CDAI components demonstrated good discriminatory power for stroke risk assessment, with an area under the curve (AUC) of 77.4%. The study highlights the potential protective role of a diet rich in antioxidants in reducing stroke risk. However, the study's cross-sectional design limits the ability to establish causality, and further research is needed to confirm these findings. The results suggest that promoting dietary choices high in antioxidants could be an important preventive strategy for stroke.This study investigates the association between the composite dietary antioxidant index (CDAI) and the prevalence of stroke in the U.S. population using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. The CDAI is a measure of antioxidant intake derived from various dietary sources, including vitamins, minerals, and phytochemicals. The study found that higher CDAI scores were associated with a lower risk of stroke, with an odds ratio (OR) of 0.96 (95% CI: 0.94-0.98) after adjusting for confounding variables. The association was nonlinear, with a significant decrease in stroke risk up to a certain threshold, after which the protective effect stabilized. Subgroup analyses showed that the association was consistent across different populations, including gender, age, race, and BMI categories. A predictive nomogram model based on CDAI components demonstrated good discriminatory power for stroke risk assessment, with an area under the curve (AUC) of 77.4%. The study highlights the potential protective role of a diet rich in antioxidants in reducing stroke risk. However, the study's cross-sectional design limits the ability to establish causality, and further research is needed to confirm these findings. The results suggest that promoting dietary choices high in antioxidants could be an important preventive strategy for stroke.