The 12-week trial, published in the journal Cancer Prevention Research, included 291 participants who lived in a rural farming community in the Chinese province of Jiangsu - about 50 miles from Shanghai, the largest city by population in the world.
According to the US and Chinese researchers, the participants given the broccoli drink increased their rate of benzene excretion by 61% on the first day and sustained this rate throughout the 12-week period. For the irritant acrolein, the rate of excretion increased by 23% during the trial. Urine and blood samples were taken before and during the trial to determine these rates.
Professor John Groopman, one of the study’s authors, said air pollution was a complex and pervasive public health problem.
"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," he said.
Participants in the control group drank a beverage made of sterilised water, pineapple and lime juice, while the beverage for the treatment group also contained a dissolved freeze-dried powder made from broccoli sprouts that contained glucoraphanin and sulforaphane. The researchers said the broccoli sprout beverage provided daily doses of 600 micromolars (µmol) of glucoraphanin and 40 µmol of sulforaphane.
The researchers said broccoli sprouts were a convenient and rich source of the glucoraphanin, which produced the chemopreventive agent sulforaphane when chewed or swallowed.
“It acts to increase enzymes that enhance the body's capacity to expunge these types of the pollutants,” they said.
Food strategies to tackle pollution
According to the World Health Organisation, air pollution may be behind as many as seven million deaths a year globally. Professor Thomas Kensler, another Johns Hopkins Bloomberg School researcher behind the paper, said the findings should be considered while governments and policy makers define and implement more effective regulation to improve air quality.
"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," Kensler said.
Of the 291 participants, 62 were men and 229 were women, with an average age of 53 (ranging from 21-65 years old).
Source: Cancer Prevention Research
Published online ahead of print, doi: 10.1158/1940-6207.CAPR-14-0103
"Rapid and Sustainable Detoxification of Airborne Pollutants by Broccoli Sprout Beverage: Results of a Randomized Clinical Trial in China"
Authors: P. A. Egner, J. Guo Chen, A. T. Zarth, D. Ng, J. Wang, K. H. Kensler, L. P. Jacobson, A. Munoz, J. L. Johnson, J. D. Groopman, J. W. Fahey, P. Talalay, J. Zhu, T. Y. Chen, G. S. Qian, S. G. Carmella,
S. S. Hecht and T. W. Kensler