Exposure to air pollutants is associated with an increased risk of developing many health disorders, including heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections. Some evidence suggests that exposure to air pollution can impair neurological development in children. A 2014 study showed that reducing exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with improved cognitive development and increased BDNF levels in children.

Polycyclic aromatic hydrocarbons are produced during the combustion of coal, oil, gasoline, trash, tobacco, and wood. High-temperature cooking, such as grilling, promotes the formation of PAHs in meat and other foods. PAHs promote the formation of DNA adducts – covalent modifications of DNA that can drive carcinogenesis.

The study involved two cohorts of mother-child pairs who lived near a coal plant in China. One cohort of pairs was made up of 150 women who were pregnant while the coal power plant was operational and the other was made up of 158 women who were pregnant after it closed. None of the women smoked, and they all lived within 2.5 kilometers (about 1.5 miles) from the coal plant.

The authors of the study analyzed BDNF levels and their relationship to adduct formation and developmental outcomes in the two cohorts. They collected umbilical cord blood and maternal blood samples and measured the amount of DNA adducts in the samples. They also measured plasma levels of BDNF. When the children reached the age of two years, they underwent standardized testing that assessed motor, adaptive, language, and social development.

The children who were born to women who were pregnant after the plant closed had lower levels of PAH-DNA adducts, higher concentrations of BDNF, and higher developmental scores than those who were born to women who were pregnant when the plant was operational. Higher BDNF levels were associated with developmental scores. The findings suggest that reducing exposure to air pollutants during pregnancy lowers levels of PAH-DNA adducts and increases BDNF levels in infants.

Interestingly, clinical trials have demonstrated that sulforaphane, a compound derived from cruciferous vegetables (especially broccoli sprouts), can reduce the harmful effects of exposure to air pollutants (including PAHs) in humans. Sulforaphane works by switching on the activity of the body’s in-house detoxication pathways. Learn more about sulforaphane in this podcast featuring Dr. Jed Fahey.

• Link to full study.