A daily broccoli sprout drink helped people in a heavily polluted area of China rid their bodies of an airborne cancer-causing chemical and lung irritant, scientists report.
In a clinical trial, researchers used the broccoli beverage to get nearly 300 Chinese men and women to consume sulforaphane, a plant compound already demonstrated in animal studies to have cancer-preventive properties.
The cruciferous cocktail produced rapid, significant, and sustained higher levels of excretion of the two air pollutants: benzene, a known human carcinogen, and acrolein, a lung irritant.
“Air pollution is a complex and pervasive public health problem,” says John Groopman, professor of environmental health at the Johns Hopkins Bloomberg School of Public Health.
“In addition to the engineering solutions to reduce regional pollution emissions,” he says, “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.”
Groopman and colleagues report their results online in Cancer Prevention Research.
Air pollution, an increasing global problem, causes as many as 7 million deaths a year worldwide, according to the World Health Organization, and has reached perilous levels in many parts of China. Last year, the International Agency for Research on Cancer classified air pollution and particulate matter from air pollution as carcinogenic to humans.
The broccoli sprout compound
Diets rich in cruciferous vegetables, including 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 someone chews the plant or swallows the beverage. Sulforaphane acts to increase enzymes that enhance the body’s capacity to expel these types of the pollutants.
The trial included 291 residents of a rural farming community in Jiangsu Province, about 50 miles north of Shanghai, one of China’s more heavily industrialized regions.
Controls drank sterilized water, pineapple, and lime juice while the half-cup daily drink for the treatment group also contained dissolved freeze-dried powder made from broccoli sprouts. The powder contained glucoraphanin and sulforaphane. Urine and blood samples were taken over 12 weeks to measure the fate of the inhaled air pollutants.
Among participants receiving the broccoli sprout beverage, excretion of benzene increased 61 percent beginning the first day and continuing throughout the 12-week trial. Acrolein excretion rapidly and durably increased 23 percent.
Secondary analyses suggested that sulforaphane may exert its protective actions by activating a signaling molecule, NRF2, that elevates the capacity of cells to adapt to and survive a broad range of environmental toxins. This strategy may also be effective for some contaminants in water and food.
Cutting health risk
“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,” notes coauthor Thomas Kensler, professor of toxicological science at the Bloomberg School.
“This while government leaders and policy makers define and implement more effective regulatory policies to improve air quality.”
More clinical trials, to evaluate optimal dosage and frequency of the broccoli sprout beverage for preventing disease, are planned in the same general region of China.
The National Institutes of Health paid for the work. Safeway Inc. donated the lime juice used in the study.
Source: Johns Hopkins University