This study investigated the association between dietary antioxidant intake and chronic respiratory diseases (CRDs) in adults using data from the 2001-2018 National Health and Nutrition Examination Survey (NHANES). A total of 40,557 participants were analyzed, with dietary antioxidant intake measured using the Composite Dietary Antioxidant Index (CDAI), which combines vitamins A, C, E, zinc, selenium, and carotenoids. CRDs were defined based on self-reported physician diagnoses, including asthma, emphysema, and chronic bronchitis. The study found that higher CDAI scores were associated with a lower prevalence of CRDs, particularly emphysema and chronic bronchitis. Individuals in the fourth quartile of CDAI scores had a 19% lower prevalence of CRDs compared to those in the first quartile. The relationship between CDAI and CRD prevalence was non-linear, with an inflection point at 3.20. Stratified analyses did not identify significant variables affecting the results. The study suggests that higher dietary antioxidant intake may help reduce the risk of CRDs, especially in adults. Antioxidants, including vitamins A, C, and E, zinc, selenium, and carotenoids, play a protective role by reducing oxidative stress and inflammation, which are linked to CRD development. The findings highlight the potential benefits of antioxidant-rich diets in improving lung health and reducing the prevalence of CRDs. However, the study has limitations, including its cross-sectional design and the potential for confounding factors. Further research is needed to confirm these findings and explore the mechanisms underlying the protective effects of dietary antioxidants against CRDs.This study investigated the association between dietary antioxidant intake and chronic respiratory diseases (CRDs) in adults using data from the 2001-2018 National Health and Nutrition Examination Survey (NHANES). A total of 40,557 participants were analyzed, with dietary antioxidant intake measured using the Composite Dietary Antioxidant Index (CDAI), which combines vitamins A, C, E, zinc, selenium, and carotenoids. CRDs were defined based on self-reported physician diagnoses, including asthma, emphysema, and chronic bronchitis. The study found that higher CDAI scores were associated with a lower prevalence of CRDs, particularly emphysema and chronic bronchitis. Individuals in the fourth quartile of CDAI scores had a 19% lower prevalence of CRDs compared to those in the first quartile. The relationship between CDAI and CRD prevalence was non-linear, with an inflection point at 3.20. Stratified analyses did not identify significant variables affecting the results. The study suggests that higher dietary antioxidant intake may help reduce the risk of CRDs, especially in adults. Antioxidants, including vitamins A, C, and E, zinc, selenium, and carotenoids, play a protective role by reducing oxidative stress and inflammation, which are linked to CRD development. The findings highlight the potential benefits of antioxidant-rich diets in improving lung health and reducing the prevalence of CRDs. However, the study has limitations, including its cross-sectional design and the potential for confounding factors. Further research is needed to confirm these findings and explore the mechanisms underlying the protective effects of dietary antioxidants against CRDs.