Vitamin C Supplementation and Protective Effects Against Exposure to Air Pollution

Vitamin C supplementation may protect against particulate matter (PM) exposure in vascular vessels. These findings were published in Ecotoxicology and Environmental Safety.

This study was conducted at Hebei Medical University in China. College students (N=58) who did not smoke cigarettes, consume alcohol regularly, or have a chronic disease were recruited between 2018 and 2019. Participants were randomly assigned to first receive vitamin C or placebo for 1 week and crossed over to the other treatment after a 2-week wash-out period. During the study, participants recorded their dietary intake and daily activity. Blood pressure measurements and blood samples were collected at the end of each intervention period. Concentrations of fine particulate matter with diameters of 2.5 (PM_2.5) and 10 (PM₁₀) μm, temperature, and relative humidity data were also collected.μ

The study participants comprised 34 men and 24 women, aged mean 20.1±3.0 years, and BMI was 22.1±3.6. During the intervention and placebo stage of the study, participants reported consuming 45.66±65.29 mg and 57.66±57.58 mg of dietary vitamin C, respectively (P =.218).

The monitoring data indicated a mean PM_2.5 of 164.91 (range, 41.33-451.46) μg/m³ and PM₁₀ of 327.05 (range, 134.03-884.54) mg/m³ throughout the study. According to the Environmental Protection Department of Hebei Provence, PM_2.5 was 159.93 (range, 48.00-349.00) μg/m³, PM₁₀ was 255.57 (range, 117.00-480.00) μg/m³, the temperature was 1.45°C (range, -3.50°C to 7.10°C), and humidity was 40.47% (range, 20.10%-82.60%).

During the intervention there were significant changes in the following health endpoints:

·   systolic blood pressure (BP): change, -3.37%; P =.001

·   pulse pressure: change, -6.03%; P =.001

·   glutathione peroxidase (GSH-Px): change, 7.15%; P =.001

·   interleukin (IL)-6: change, -19.47%; P <.001

·   tumor necrosis factor-∝ (TNF-∝): change, -17.30%; P <.001

·   C-reactive protein (CRP): change, -34.01%; P <.001

Stratified by gender, vitamin C supplementation had a significant gender interaction for superoxide dismutase (change, 10.67%; P =.012), in which superoxide dismutase increased in men (change, 2.40%) and decreased in women (change, -5.30%).

In 3 pollutant models, air pollution had significant effects on systolic blood pressure, pulse pressure, GSH-Px, IL-6, TNF-∝, and CRP.

The major limitation of this study was recruiting healthy, young individuals. It remains unclear whether these findings are generalizable.

“Our study provides preliminary evidence that vitamin C supplementation is a simple and effective way to protect vascular health against air pollution in areas with very high air pollution levels,” the study authors wrote. “Although these findings still need to be verified with further investigation, our study provided novel support for the prevention of adverse vascular effect of air pollutant exposure.”

Disclosure: None of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies.  

Reference

Ren J, Liang J, Wang J, et al. Vascular benefits of vitamin C supplementation against fine particulate air pollution in healthy adults: A double-blind randomised crossover trial. Ecotoxicol Environ Saf. Published online June 8, 2022. doi:10.1016/j.ecoenv.2022.113735