Researchers at Johns Hopkins University School of Medicine found sulforaphane sourced from broccoli sprouts and broccoli seeds may be equally bioavailable.
Photo © iStockphoto.com/MarenWischnewski
Researchers at Johns Hopkins University (JHU) School of Medicine (Baltimore, Maryland) recently found that sulforaphane may be equally bioavailable if sourced from broccoli sprouts or from commercially available glucoraphanin supplements sourced from broccoli seeds.
Glucoraphanin is a “dietary precursor” of the antioxidant sulforaphane, an isothiocyanate with cancer-protecting properties that the researchers describe as “one of the most potent known, naturally occurring inducers of cytoprotective phase 2 enzymes.” When a person consumes broccoli, the inert glucoraphanin and the enzyme myrosinase (also present in broccoli) begin to interact and the glucoraphanin is converted into the antioxidant sulforaphane.
The new crossover clinical trial compared the bioavailability of sulforaphane from broccoli sprouts with the bioavailability of sulforaphane from supplements that contained Truebroc glucoraphanin powder, provided by Brassica Protection Products (Baltimore, MD). Researchers found that the two different sources of sulforaphane were “equally bioavailable.”
According to Jed Fahey, ScD, lead author of the study, JHU researchers have studied the bioavailability of sulforaphane from broccoli sprout extracts in the past, but this is the first study to look at “commercially available glucoraphanin-rich product made from broccoli seeds.”
“The study demonstrated that these specific glucoraphanin supplements are equally bioavailable to the glucoraphanin-rich broccoli sprout extract we have used in previous clinical studies,” says Fahey. “From a public health perspective, this study will pave the way for future research on the efficacy of over-the-counter glucoraphanin supplements.”
The study included a participant group of 17 adults with an average age of 51 years. Each participant consumed four different glucoraphanin preparations in random order, with one week separating each dose. The doses were 30 mg or 100 mg of glucoraphanin sourced from either JHU-made broccoli sprout extract or OncoPLEX dietary supplements made with Brassica’s Truebroc powder. Xymogen (Orlando, FL) produces the OncoPLEX supplements containing Truebroc that were used in the study.
Following each dose, researchers measured the excretion of sulforaphane metabolites in the participants’ urine to compare the bioavailability of the broccoli sprout extract with the OncoPLEX supplements. The two sources were found to be statistically equivalent, with the 30 mg glucoraphanin dose averaging a 12.8% conversion for the broccoli sprout preparation and a 11.2% conversion for the OncoPLEX broccoli seed supplement preparation. For the 100 mg glucoraphanin dose, the broccoli sprout preparation yielded a 8.3% average conversion, compared with a 9.7% average conversion for the OncoPLEX supplement.
Brassica says the study findings “validate the use of high-quality glucoraphanin supplements to help support the body’s detoxification pathways and eliminate toxins," in a press release.
“While supplements are not intended to substitute for a balanced diet with nutrient-packed vegetables such as broccoli, consumers now have the assurance of knowing that high-quality glucoraphanin supplements from broccoli seeds can help to support the body’s own natural detoxification processes,” says Tony Talalay, CEO, Brassica.
Nutritional Outlook Magazine
Fahey JW et al, “Sulforaphane bioavailability from glucoraphanin-rich broccoli: control by active endogenous myrosinase,” PLoS One, vol. 10, no. 11 (November 2015): e0140963.