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

Abstract

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.

Keywords: Carotenoids; Chinese; Cohort study; Flavonoids; Mortality; Vitamins.