Abstract
Background: Accumulating evidence indicates that ambient air pollution exposure is associated with the adverse effects of cardiovascular diseases (CVDs). Evidence on the health benefits of vitamin C supplementation in highly polluted areas has not been evaluated. Objectives: We aims to evaluate whether dietary vitamin C supplementation can improve cardiovascular health linked to PM exposure. Methods: A randomized double-blind crossover trial was performed in 58 health young adults in Shijiazhuang, China in 2018. All subjects were randomly assigned to vitamin C supplementation or placebo group for a week alternating with a two-week washout period. We measured blood pressure (BP), blood lipid, biomarkers of oxidative and biomarkers of inflammation. Linear mixed-effect model was applied to evaluate the effect of vitamin C supplementation on health outcomes.Results: During the intervention periods, the average concentration of PM2.5 and PM10 was 164.91μg/m3 and 327.05μg/m3, respective. Vitamin C supplementation was significantly associated with decrease in several inflammatory indicators and blood pressure, including 19.47% in interleukin-6 (IL-6), 17.30% in tumor necrosis factor-a (TNF-α), 34.01% in C-reactive protein (CRP), 3.37% in systolic blood pressure (SBP) and 6.03% in pulse pressure (PP). Further, glutathione peroxidase (GSH-Px) was significantly increased by 7.15%. The effect of nutritional intervention on other indicators were beneficial, but there was no statistical difference. Gender-subgroup analysis showed that vitamin C supplementation significantly reduced SBP by 3.31%, PP by 4.94%, IL-6 by 20.97%, TNF-α by 27.85% and CRP by 38.5% in males, and significantly reduced SBP by 3.65%, PP by 8.12%, IL-6 by 17.35% and CRP by 29.15% in females. In contrast, vitamin C supplementation significantly increased APOB by 6.28% and GSH-Px by 14.47% in female participants only. Conclusion: This study indicates that vitamin C supplementation may protect cardiovascular system against particulate matter (PM) exposure among healthy young adults in China.Clinical trial registration information: Identifier: ChiCTR2100051371. Registered 19 October 2018, https://www.chictr.org.cn.