Independent and combined associations of dietary antioxidant exposure with all-cause and cause-specific mortality in the general population

Abstract

Abstract This study aimed to determine if habitual intake of key dietary antioxidants, both individually and collectively, is associated with all-cause and cause-specific mortality among U.S. adults, given that oxidative stress heightens cardiovascular and cancer mortality risk. This prospective cohort study analysed 34,955 participants from the National Health and Nutrition Examination Survey (NHANES) 2003–2018. Intakes of vitamins A, C, E, zinc, selenium, and carotenoids were assessed, and a composite dietary antioxidant index (CDAI) was calculated. The principal results, from 347,580 person-years of follow-up where 4,456 deaths occurred (1,368 CVD; 1,038 cancer), showed significant associations. Compared with the lowest intake quintile, the highest quintile of vitamin E was associated with lower all-cause mortality (HR: 0.69, 95% CI: 0.58–0.83) and CVD mortality (HR: 0.67, 0.48–0.92). High carotenoid intake was inversely associated with all-cause mortality (HR: 0.77, 0.67–0.88). Participants in the highest CDAI quintile experienced an 18% lower risk of all-cause mortality (HR: 0.82, 0.70–0.97) and a 39% lower risk of cancer mortality (HR: 0.61, 0.45–0.84). Dose–response relationships for vitamins A, C, selenium, and zinc were U-or L-shaped, and WQS analyses assigned the greatest weights to vitamin A or C. In conclusion, while individual antioxidants like vitamin E show strong protective associations, the evidence collectively suggests that greater overall antioxidant exposure from a varied diet is linked to materially lower risks of death. This reinforces that focusing on diets rich in diverse antioxidant sources is superior to single-nutrient strategies.