Dietary total antioxidant capacity and mortality outcomes: the Singapore Chinese Health Study

Purpose To evaluate the relations of dietary total antioxidant capacity (DTAC) with mortality outcomes in a Chinese population. Methods The study included 62,063 participants from the Singapore Chinese Health Study. The participants were 45-74 years at baseline (1993-1998) when dietary data were collected with a validated 165-item food frequency questionnaire. The DTAC was derived using two widely adopted scores of integrated dietary consumption of antioxidant nutrients, i.e., the Comprehensive Dietary Antioxidant Index (CDAI) and Vitamin C Equivalent Antioxidant Capacity (VCEAC). We used Cox proportional hazard model to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations with adjustment for potential confounders. Results During 1,212,318 person-years of follow-up, 23,397 deaths [cardiovascular diseases (CVD): 7523; respiratory diseases: 4696; and cancer: 7713] occurred. In multivariable models, the HR (95% CI) comparing participants in the highest vs. lowest quartile of CDAI was 0.85 (0.82, 0.88) for all-cause mortality, 0.82 (0.76, 0.88) for CVD mortality, 0.76 (0.70, 0.83) for respiratory disease mortality (all P-trend < 0.001), and 0.94 (0.88, 1.00) for cancer mortality (P-trend = 0.16). Similar associations were found with the VCEAC index. Higher intakes of the DTAC components, i.e., vitamin C, vitamin E, carotenoids, and flavonoids, were all associated with lower mortality risk. Conclusion Diet with a higher antioxidant capacity in midlife was associated with a lower risk of all-cause, cardiovascular and respiratory disease mortality in the Singapore Chinese population, supporting the public health recommendation of consuming more plant-based foods that are rich in antioxidant nutrients.