The study, published online in the journal Cancer Prevention Research , found the beverage produced "rapid, significant, and sustained higher levels of excretion of benzene, a known human carcinogen, and acrolein, a lung irritant," said the researchers from the Johns Hopkins Bloomberg School of Public Health.



They added that a plant compound in the beverage, sulforaphane, has been shown to have potent anti-cancer properties in animal studies.



"Air pollution is a complex and pervasive public health problem," noted John Groopman, a professor of environmental health at Johns Hopkins and one of the study's co-authors. "To address this problem comprehensively, in addition to the engineering solutions to reduce regional pollution emissions, we need to translate our basic science into strategies to protect individuals from these exposures. This study supports the development of food-based strategies as part of this overall prevention effort."



Air pollution causes as many as seven million deaths a year worldwide, according to the World Health Organization. Last year, the International Agency for Research on Cancer classified air pollution and particulate matter from air pollution as carcinogenic to humans.



Diets rich in cruciferous vegetables, such as broccoli, have been found to reduce risk of chronic degenerative diseases, including cancer. Broccoli sprouts are a source of glucoraphanin, a compound that generates sulforaphane when the plant is chewed or a beverage made from the vegetable is swallowed. It increases enzymes that enhance the body's ability to eliminate such pollutants.



The 12-week study included 291 people from a heavily industrialize area in Jiangsu Province, China. Some drank an inactive placebo beverage made of sterilized water, pineapple, and lime juice while the treatment group consumed a dissolved freeze-dried powder made from broccoli sprouts that contained glucoraphanin and sulforaphane.



The results showed men and women who drank the broccoli sprout beverage excreted 61 percent more of the carcinogen benzene than before the start of the study. In addition, the rate of excretion of the irritant acrolein, rapidly and durably increased 23 percent during the 12-week trial.



"This study points to a frugal, simple and safe means that can be taken by individuals to possibly reduce some of the long-term health risks associated with air pollution," noted Thomas Kensler, a professor at Johns Hopkins and a study co-authors. "This while government leaders and policy makers define and implement more effective regulatory policies to improve air quality."



The study was funded, in part, by the National Institutes of Health.

Johns Hopkins researchers have come up with yet another reason to eat — or even drink — your broccoli. A clinical trial involving nearly 300 men and women living in one of China's most polluted regions found that daily consumption of a half-cup of a broccoli sprout beverage helped rid their bodies of cancer-causing contaminants.