News Release

Taking B vitamins may reduce epigenetic effects of air pollution

Peer-Reviewed Publication

Columbia University's Mailman School of Public Health

A new study by researchers at Columbia University's Mailman School of Public Health showed that B vitamins may play a critical role in reducing the impact of air pollution on the epigenome, further demonstrating the epigenetic effects of air pollution on health. This is the first study to detail a course of research for developing interventions that prevent or minimize the adverse effects of air pollution on potential automatic markers. The results are published online in the journal PNAS.

The study, conducted with colleagues at Harvard's T. H. Chan School of Public Health, in Sweden, China, Singapore, Mexico and Canada, reveals how individual-level prevention may be used to control the potential pathways underlying adverse effects of the particles PM2.5, particles with an aerodynamic diameter of <2.5 μm. These findings could have a significant public health benefit in regions of the world with frequent PM2.5 peaks.

"The molecular foundations of air pollution's health effects are not fully understood, and the lack of individual-level preventative options represented a critical knowledge gap," said Andrea Baccarelli, MD, PhD, professor and chair of Environmental Health Sciences at the Mailman School. "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."

The WHO estimates that 92 percent of the world's population currently lives in places where air quality levels exceed the WHO limits of 10 μg/m3.

Ambient PM2.5 pollution is one of the most prominent air pollutants because they deposit in the respiratory tract resulting in both lung and systemic inflammation and stress. While there has been substantial lowering of ambient PM2.5 achieved through large-scale emissions control policies over the past few decades, exposure peaks with adverse health consequences are still frequently recorded.

"The health effects of air pollution and how it plays a role in one's health raise many complex issues," said Jia Zhong, principal investigator, and postdoctoral research officer in the Department of Environmental Health Sciences. "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."

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 recruited for the trial. To take part in the intervention, volunteers were required to be healthy non-smokers, 18 to 60 years old, who were not taking any medicines or vitamin supplements.

Plasma B vitamin measurements taken before and after placebo and supplementation showed that B-vitamin supplements 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). For those who 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). All exposure experiments were conducted at the same time of the day.

Ambient particles were drawn from an inlet next to a heavily trafficked street in downtown Toronto with more than 1000 vehicles passing through each hour. Particles were delivered via an "oxygen type" facemask. Blood samples were collected and measured using the Infinium Human Methylation 450K BeadChip.

"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. Future studies, especially in heavily polluted areas, are urgently needed to validate our findings and ultimately develop preventive interventions using B vitamins to contain the health effects of air pollution," said Dr. Baccarelli.


The study was supported by National Institutes of Health (Grants R21ES021895, R01ES015172, R01ES021733, R01ES020836, R01ES021357, and P30ES000002); U.S. Environmental Protection Agency (Grant RD-83479801); Environment Canada; AllerGen NCE; and National Natural Science Foundation of China Grant 91643202. See the paper for full list of co-authors.

Columbia University's Mailman School of Public Health

Founded in 1922, Columbia University's Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master's and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including ICAP (formerly the International Center for AIDS Care and Treatment Programs) and the Center for Infection and Immunity. For more information, please visit

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