As children, many of us were forced to finish all the broccoli on our dinner plates, but new research from the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, suggests new benefits of the green vegetable.
Study participants from one of the most polluted regions in China who consumed half a cup of broccoli sprout beverage were shown to excrete high levels of benzene and acrolein - a known human carcinogen and lung irritant, respectively.
The Johns Hopkins researchers note that diets rich in cruciferous vegetables, such as broccoli, have previously been found to reduce the risk of several chronic diseases, including cancer.
But broccoli in particular is a source of glucoraphanin - a compound that generates sulforaphane when the vegetable is chewed or the beverage is swallowed.
The researchers explain that sulforaphane increases enzymes that improve the body's ability to get rid of pollutants in the body, which is why the study participants exhibited significantly high levels of excreted benzene and acrolein.
The 'complex and pervasive' problem of air pollution
According to the Agency for Toxic Substances & Disease Registry, an arm of the Centers for Disease Control and Prevention (CDC), increases in air pollution have been linked to decreases in lung function and increases in heart attacks. Poor air quality can also affect people with asthma and other types of lung or heart disease.
In March of this year, Medical News Today reported on a study from the World Health Organization, which suggested around 1 in 8 global deaths - or 7 million deaths annually - are a result of exposure to air pollution.
And last year, the International Agency for Research on Cancer classified air pollution and particulate matter as carcinogenic to humans, say the researchers. But in many parts of China, air pollution has reached dangerous levels.
Prof. John Groopman, study author from Johns Hopkins, says:
"Air pollution is 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."
He adds that their study "supports the development of food-based strategies as part of this overall prevention effort."
Broccoli: 'frugal, simple and safe way to minimize pollution's effects'
For 12 weeks, the research team studied 291 participants who lived in a rural farming community in Jiangsu Province, China. This is an area around 50 miles north of Shanghai - a heavily industrialized region in the country.
In total, there were 62 men and 229 women, whose ages ranged from 21 to 65. Their urine and blood samples were taken during the trial to assess measurements of inhaled air pollutants.
The study participants were split into two groups. The control group drank a beverage consisting of sterilized water, pineapple and lime juice. The treatment group drank the same beverage, but it also contained a dissolved freeze-dried powder made from broccoli sprouts, which contained both glucoraphanin and sulforaphane.
Results showed that the participants in the treatment group exhibited a 61% increased rate of excretion of the carcinogen benzene on day one, and this continued during the following 12 weeks.
Additionally, their rate of excretion of the irritant acrolein increased by 23%, compared with the placebo group during the study.
After conducting a secondary analysis, the team says sulforaphane may be activating a signaling molecule - called NRF2 - that increases the ability of cells to adapt to and survive a wide range of environmental toxins.
This strategy may also be used for contaminants in water and food, the team adds.
Prof. Thomas Kensler, study co-author from Johns Hopkins, says:
"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. This while government leaders and policy makers define and implement more effective regulatory policies to improve air quality."
They are planning further clinical trials in the same region of China to assess the best dosage and frequency of the broccoli sprout beverage.
Meanwhile, Medical News Today recently reported on a study that suggested high exposure to traffic pollution is linked to changes in the mass and size of the heart's right chamber.
For more information on the health benefits of broccoli, see our Knowledge Center article.