Nearly four million women living in the United States have a history of breast cancer. Evidence suggests that dietary interventions improve breast cancer outcomes and enhance survival. Findings from a recent study indicate that consumption of an isothiocyanate-rich broccoli sprout extract may improve outcomes in women with breast cancer.
Isothiocyanates are byproducts of a reaction between compounds present in cruciferous vegetables. Isothiocyanates inhibit the activity of enzymes that transform procarcinogens into carcinogens. One of the most studied isothiocyanates is sulforaphane, which is derived from broccoli and is particularly abundant in broccoli sprouts.
The study involved 30 women (average age, 61 years) who were about to undergo surgery to remove breast cancer tumors. The investigators randomly assigned half of the women to receive 200 micromoles of isothiocyanates from a broccoli sprout extract every day for two weeks prior to their surgery. (This daily dose of broccoli sprout extract is roughly equivalent to that provided in 500 grams – a little more than one pound – of fresh broccoli.) The remaining half of the women received a placebo. The investigators measured isothiocyanate metabolites and cytoprotective proteins in the women’s urine and biomarkers of anticancer activity in the excised tumor tissue.
They identified multiple proteins in the participants' urine that indicated increased activity of cytoprotective pathways, including the Nrf2-mediated oxidative response pathway. They also observed changes in biomarkers of anticancer activity, including a trend toward increased levels of proteins that regulate programmed cell death and immune cells that recognize and kill cancer cells, as well as a trend toward decreased levels of proteins involved in proliferation. These changes were not statistically significant, however.
These findings indicate that consumption of an isothiocyanate-rich broccoli sprout extract may improve outcomes in women with breast cancer. The authors posited that the absence of statistically significant findings was likely due to their small sample size and suggested further study with a larger sample.