The study is the first to investigate the potential of developing interventions that prevent or minimize the adverse effects of air pollution.
Led by Professor Andrea Baccarelli from Harvard's T. H. Chan School of Public Health, the team noted World Health Organisation (WHO) figures that estimate 92% of the world's population currently lives in places where air quality levels exceed the recommended limits of 10 μg/m3.
“Our study demonstrated the epigenetic effects of air pollution and suggested that B vitamins might be used as prevention to complement regulations to attenuate the impact of air pollution on the epigenome,” said the authors, writing in PNAS.
Baccarelli added that while the molecular foundations of air pollution's health effects are not fully understood, the lack of preventative options represented a ‘critical knowledge gap’.
"While emission control and regulation is the backbone of prevention, high exposures are, unfortunately, the rule still in many megacities throughout the world,” he said. “As individuals, we have limited options to protect ourselves against air pollution.”
The trial randomly gave a small group of participants a B-vitamin supplement (2.5 mg of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12) or a placebo. After initial blood measures were taken the group were then exposed to ambient pollution with a particulate matter smaller than 2.5 μm (known as PM2.5).
They found that exposure to the particulate matter caused epigenetic changes, including alteration to methylation of genes involved in mitochondrial oxidative energy metabolism.
However, supplementation with the B-vitamins was found to prevent these changes when exposed to the polluted air.
"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.
He added that future studies, especially in heavily polluted areas, ‘are urgently needed’ to confirm the findings “and ultimately develop preventive interventions using B vitamins to contain the health effects of air pollution."
Published online ahead of print, doi: 10.1073/pnas.1618545114
“B vitamins attenuate the epigenetic effects of ambient fine particles in a pilot human intervention trial”
Authors: Jia Zhong, et al