Shanghai: A human trial conducted in China shows broccoli sprouts can help the body detoxify carcinogens, which may reduce the risk of developing liver cancer.
A team from Johns Hopkins University School of Medicine and Bloomberg School of Public Health, in collaboration with scientists at the Qidong Liver Cancer Institute, Jiao Tong University in Shanghai and the University of Minnesota Cancer Center, conducted the study. It is published in the November issue of Cancer Epidemiology Biomarkers & Prevention.
This is the first study to provide direct evidence that broccoli sprouts can enhance the body’s detoxifying system to help prevent cancer. Although previous laboratory studies indicated this was true, this is the first time that a direct observation of this effect in humans was possible.
The blinded, placebo-controlled study was conducted in Jiangsu Province near Shanghai, a rural area where the incidence of liver cancer is extremely high due to consumption of foods tainted with aflatoxin, a powerful carcinogen produced by mold contaminating the grain that the population grows and eats. The toxin binds to DNA and becomes a chemical indicator, or biomarker, for an increased risk of developing liver cancer.
Three-day-old broccoli sprouts with known levels of sulforaphane glucosinolate (SGS) were grown at the site in China and prepared as a liquid extract to ensure standard dosages. One hundred test subjects drank 5 ounces of the extract (equivalent to eating about 2 ounces of broccoli sprouts) each day for 2 weeks. A control group drank a similar extract that contained virtually no SGS.
Tests of subjects’ urine showed carcinogens were being detoxified and removed from the body in those who drank the SGS extract. As the levels of sulforaphane derivatives in the urine increased, the amount of DNA damage decreased, which may indicate a reduction in cancer risk.
“While this study did not directly look at liver cancer, it is clear that liver cancer has had devastating consequences in this region of China and in other parts of the world. This study is an initial step in evaluating dietary methods for preventing this disease, and it may be applicable to other types of cancers,” said participating epidemiologist Jian-Guo Chen, MD, of the Qidong Liver Cancer Institute.
Further studies are in the planning phases to examine dose levels and implications for other high-risk populations.
In 1992, scientists at Johns Hopkins first determined that broccoli contained high levels of the long-lasting antioxidant sulforaphane. In 1997, they discovered that 3-day-old broccoli sprouts contained more than a 20 times higher concentration of SGS than mature broccoli.
More than 350 studies have appeared in peer-reviewed scientific publications pointing to sulforaphane and SGS from broccoli and broccoli sprouts as powerful health protectors.