B-vitamin Supplementation Mitigates Effects of Fine Particles on Cardiac Autonomic Dysfunction and Inflammation: A Pilot Human Intervention Trial

Ambient fine particle (PM(2.5)) pollution triggers acute cardiovascular events. Individual-level preventions are proposed to complement regulation in reducing the global burden of PM(2.5)–induced cardiovascular diseases. We determine whether B vitamin supplementation mitigates PM(2.5) effects on cardiac autonomic dysfunction and inflammation in a single-blind placebo-controlled crossover pilot trial. Ten healthy adults received two-hour controlled-exposure-experiment to sham under placebo, PM(2.5) (250 μg/m(3)) under placebo, and PM(2.5) (250 μg/m(3)) under B-vitamin supplementation (2.5 mg/d folic acid, 50 mg/d vitamin B(6), and 1 mg/d vitamin B(12)), respectively. At pre-, post-, 24 h-post-exposure, we measured resting heart rate (HR) and heart rate variability (HRV) with electrocardiogram, and white blood cell (WBC) counts with hematology analyzer. Compared to sham, PM(2.5) exposure increased HR (3.8 bpm, 95% CI: 0.3, 7.4; P = 0.04), total WBC count (11.5%, 95% CI: 0.3%, 24.0%; P = 0.04), lymphocyte count (12.9%, 95% CI: 4.4%, 22.1%; P = 0.005), and reduced low-frequency power (57.5%, 95% CI: 2.5%, 81.5%; P = 0.04). B-vitamin supplementation attenuated PM(2.5) effect on HR by 150% (P = 0.003), low-frequency power by 90% (P = 0.01), total WBC count by 139% (P = 0.006), and lymphocyte count by 106% (P = 0.02). In healthy adults, two-hour PM(2.5) exposure substantially increases HR, reduces HRV, and increases WBC. These effects are reduced by B vitamin supplementation.