Dietary antioxidant capacity and all-cause and cause-specific mortality in the E3N/EPIC cohort study

Purpose The cellular oxidative stress (balance between pro-oxidant and antioxidant) may be a major risk factor for chronic diseases. Antioxidant capacity of human diet can be globally assessed through the dietary non-enzymatic antioxidant capacity (NEAC). Our aim was to investigate the relationship between the NEAC and all-cause and cause-specific mortality, and to test potential interactions with smoking status, a well-known pro-oxidant factor. Methods Among the French women of the E3N prospective cohort study initiated in 1990, including 4619 deaths among 1,199,011 persons-years of follow-up. A validated dietary history questionnaire assessed usual food intake; NEAC intake was estimated using a food composition table from two different methods: ferric ion reducing antioxidant power (FRAP) and total radical-trapping antioxidant parameter (TRAP). Hazard ratio (HR) estimates and 95 % confidence intervals (CI) were derived from Cox proportional hazards regression models. Results In multivariate analyses, FRAP dietary equivalent intake was inversely associated with mortality from all-causes (HR for the fourth vs. the first quartile: HR 4 = 0.75, 95 % CI 0.67, 0.83, p trend < 0.0001), cancer, and cardiovascular diseases. Similar results were obtained with TRAP. There was an interaction between NEAC dietary equivalent intake and smoking status for all-cause and cardiovascular disease mortality, but not cancer mortality (respectively, for FRAP, p inter = 0.002; 0.013; 0.113, results were similar with TRAP), and the association was the strongest among current smokers. Conclusion This prospective cohort study highlights the importance of antioxidant consumption for mortality prevention, especially among current smokers.