UNLABELLED: In the Mexican population, low dietary antioxidant intake (DAI) is associated with reduced bone mineral density (BMD). A decline in DAI over time further contributes to BMD loss, particularly at the total hip, femoral neck, and lumbar spine, with a more pronounced effect in women over 45 years old. PURPOSE: Bone remodeling, balancing resorption and formation, is crucial for bone health. Aging shifts this balance, reducing BMD and increasing osteoporosis risk. Reactive oxygen species (ROS) contribute to bone loss through oxidative stress. Antioxidants may help mitigate this damage, but their impact on BMD in populations with inadequate nutrient intake, like Mexicans, needs to be better understood. This study explores the association between DAI changes and BMD in a Mexican population. METHODS: Data were sourced from the Health Worker Cohort Study (HWCS), including 1,318 participants (aged ≥ 20) with BMD measurements and complete dietary information at two time points. The study employed a longitudinal design was used, whit data from two waves of the study (2010-2012 and 2017-2019), providing a median follow-up time of 6.4 years for men and 6.8 years for women. Dietary antioxidant intake was assessed using a validated Food Frequency Questionnaire for the Mexican diet. BMD was measured at the femoral neck, total hip, and lumbar spine using dual-energy X-ray absorptiometry (DEXA). Fixed-effects regression models were applied to analyze the association between DAI and BMD at different sites, adjusting for time-varying covariates. RESULTS: Changes in DAI scores were associated with lower BMD at various sites. Each unit decrease in DAI over time was associated with a BMD loss of -0.002,-0.004 g/cm CONCLUSION: This study underscores the role of reduced dietary antioxidant intake in contributing lower BMD, particularly among older adults. Diets low in antioxidant may increase the risk of osteoporosis, especially in populations with insufficient nutrient intake.