by Alexandria Bachert
Staff Writer, MedPage Today
March 15, 2017

B vitamins, such as folic acid and vitamins B₆ and B₁₂, may play an important role in reducing the impact of air pollution on the epigenome, according to results from a small, placebo-controlled trial.

B-vitamin supplementation can diminish the acute effects of PM2.5, one of the most prominent air pollutants, on cardiac autonomic dysfunction and inflammatory markers, reported Andrea Baccarelli, MD, PhD, of Columbia University’s Mailman School of Public Health in New York City, and colleagues.

While PM2.5 depleted 11.1% (95% CI 0.4%, 21.7%, P=0.04) of mitochondrial DNA content compared with sham, B-vitamin supplementation attenuated the PM2.5 effect by 102% (P=0.01), they wrote in the Proceedings of the National Academy of Sciences.

“Our study launches a line of research for developing preventive interventions to minimize the adverse effects of air pollution on potential mechanistic markers. Because of the central role of epigenetic modifications in mediating environmental effects, our findings could very possibly be extended to other toxicants and environmental diseases,” said Baccarelli in a press release.

He noted that the molecular foundations of air pollution’s health effects are generally not fully understood, and that “the lack of individual-level preventative options represented a critical knowledge gap.”

Baccarelli’s group recruited 10 people, ages 18 to 60 years, from the University of Toronto campus and surrounding area. All participants were required to be healthy non-smokers and not taking any medicines or vitamin supplements.

They collected ambient particles from an inlet near a heavily trafficked street in downtown Toronto with more than 1,000 vehicles passing through each hour. Particles were then delivered via an “oxygen type” face mask, and blood samples were collected and measured using the Infinium Human Methylation 450K BeadChip, noted the researchers.

During three 4-week periods, the researchers administered one placebo or B-vitamin supplement (2.5 mg of folic acid, 50 mg of vitamin B₆, and 1 mg of vitamin B₁₂) daily to each adult.

Participants received 2-hour controlled-exposure-experiment to sham under placebo, PM2.5 (250μg/m3) under placebo, and PM2.5 (250μg/m3) under B-vitamin supplementation (2.5mg/d folic acid, 50mg/d vitamin B₆, and 1mg/d vitamin B₁₂), respectively.

At pre-, post-, 24h-post-exposure, they measured resting heart rate and heart rate variability with electrocardiogram, and white blood cell counts with hematology analyzer.

The researchers found that median plasma concentrations of folic acid and vitamins B₆and B₁₂ were 35 nmol/L (IQR 14 nmol/L), 41 nmol/L (IQR 16 nmol/L), and 292 pmol/L (IQR 72 pmol/L) before sham experiment, respectively.

After participants took placebos for 4 weeks, their median plasma concentrations were similar: 39 nmol/L (IQR 24 nmol/L) for folic acid (P=0.82), 37 nmol/L (IQR 18 nmol/L) for vitamin B₆ (P= 0.75), and 262 pmol/L (IQR 214 pmol/L) for vitamin B₁₂ (P=0.42).

B-vitamin supplementation significantly increased the median plasma concentrations of folic acid (56 nmol/L, IQR:13, P=0.02), vitamin B₆ (428 nmol/L, IQR 321, P=0.004), and vitamin B₁₂ (511 pmol/L, IQR 85, P=0.01).

The researchers concluded that individual-level prevention may be used to complement regulations and control potential mechanistic pathways underlying the adverse PM2.5 effects.

“While emission control and regulation is the backbone of prevention, high exposures are, unfortunately, the rule still in many megacities throughout the world. As individuals, we have limited options to protect ourselves against air pollution,” Baccarelli stated.

He called for future studies — especially in heavily polluted areas — in order to validate the findings, and develop preventive interventions using B vitamins to contain the health effects of air pollution.

Co-author Jia Zhong, a postdoctoral research officer at Columbia, agreed. “Until we can attack the problem on an individual level we are a long way from fully tackling its challenges for the public’s health,” he said in the press release.

Study limitations included the short duration and the inability to randomize treatment sequence due to the long half-life of B vitamins.

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner