Taking vitamin B may help lower the impact of air pollution on health by reducing its adverse effect on DNA methylation, a mechanism used by cells to control gene expression, according to new research
Scientists at Columbia University’s Mailman School of Public Health looked at whether vitamin B can help minimise DNA methylation changes induced by exposure to the pollutant PM2.5, a fine particle with a diameter of less than 2.5 micrometres.
“The molecular foundations of air pollution’s health effects are not fully understood, and the lack of individual-level preventative options represents a critical knowledge gap,” says Andrea Baccarelli, professor and chair of environmental health sciences at the Mailman school.
The study involved ten healthy, non-smoking adults aged 18 to 60 years who were not taking any medicines or vitamin supplements. Each of the adults was exposed to a placebo and fresh air (sham trial); a placebo and PM2.5 -polluted air; and a vitamin B supplement (2.5mg of folic acid, 50mg of vitamin B6, and 1mg of vitamin B12) and PM2.5 -polluted air. Air was delivered via an oxygen mask. The PM2.5 -induced methylation changes in the study participants’ genes were profiled before and after each experiment.
The researchers found that PM2.5 depleted mitochondrial DNA content by 11.1% (95% confidence interval [CI] 0.4%-21.7%; P =0.04), compared with the sham trial. However, the vitamin B supplement taken by the participants attenuated the effect of PM2.5 by 102% (P =0.01). Reducing the effects of PM2.5 at an individual level could have significant benefits to public health in areas with high levels of the pollutant, they suggest.
“Our study launches a line of research for developing preventive interventions to minimise the adverse effects of air pollution on potential mechanistic markers,” says Baccarelli. “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.”
Carrie Breton, assistant professor of preventive medicine at the University of Southern California, says that while the results are promising they should be approached carefully.
“It is a very interesting approach to try to understand whether some of the vitamin supplementation results that we have seen in animal studies may be true for humans as well. The fact that they find a coherent story in only 10 subjects is promising, but should clearly be interpreted with caution as it is a very small study,” she says.
“While I think it is great that doing something as easy as taking a vitamin would help protect against air pollution harm, the public health goal still needs to be one of reducing air pollution to a level that is not harmful.”
The researchers conclude that further studies in heavily polluted areas are urgently needed to validate the findings before developing preventive interventions using vitamin B to combat the effects of air pollution.
 Zhong J, Karlsson O, Wang G et al. B vitamins attenuate the epigenetic effects of ambient fine particles in a pilot human intervention trial. Proc Natl Acad Sci; published ahead of print March 13, 2017; doi: 10.1073/pnas.1618545114