Glucoraphanin supplements match broccoli sprouts for sulforaphane bioavailability: Study

Data published in PLoS One​​ indicated that the commercial Xymogen’s OncoPLEX supplements made from broccoli seeds produced equivalent outputs of sulforaphane metabolites in the urine as observed for equivalent doses of glucoraphanin in a simple boiled and lyophilized extract of broccoli sprouts.

“This was the first study in which we used a commercially available glucoraphanin-rich product made from broccoli seeds,”​ said lead author Jed Fahey, ScD, Johns Hopkins University School of Medicine. “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. From a public health perspective, this study will pave the way for future research on the efficacy of over-the-counter glucoraphanin supplements.”​

From glucoraphanin to sulforaphane​

Glucoraphanin is the precursor to sulforaphane, which has been identified as the most beneficial compound in broccoli and other cruciferous vegetables. Sulforaphane is a potent natural inducer of Phase 2 detoxification enzymes, which eliminate many types of free radicals and environmental pollutants, and trigger ongoing antioxidant action that lasts for as much as three days, said the company.

The enzyme myrosinase is required to convert glucoraphanin to sulforaphane, and it is often denatured during cooking, or not present in many commercial extracts. There is scientific evidence to support the production of sulforaphane from glucoraphanin by gut microflora, including Cancer Prev. Res.​​ (March 2011, Vol. 4, pp. 384-395), and Mol. Nutr. Food Res.​​ (Dec 2012, Vol. 56, pp. 1906-1916).

The Xymogen supplement used truebroc Glucoraphanin from Brassica Protection Products LLC, and Brassica’s CEO, Tony Talalay, welcomed the data.

“The recent trial at JHU Medical School demonstrates that glucoraphanin from broccoli seeds is equally as bioavailable as glucoraphanin from the broccoli sprouts that have been used by Johns Hopkins researchers and others in large-scale human trials throughout the world,”​ he said..

“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.”  ​

Study details​

The Johns Hopkins researchers recruited 20 participants with an average age of 51 years to participate in their study. Participants were given the following glucoraphanin preparations:
A broccoli sprout extract prepared by the researchers containing 30 mg or 100 mg of glucoraphanin; or the OncoPLEX supplements containing 30 mg or 100 mg of glucoraphanin.

Each participant received one dose of each preparation, and doses were separated by one week.

Data from the 17 subjects who completed the study indicated that the two sources were equally bioavailable. For the 30 mg glucoraphanin doses, the average conversions were 12.8% for the JHU broccoli sprout preparation and 11.2% for the OncoPLEX broccoli seed supplement preparation.

For the 100 mg dose of JHU-preparation and OncoPLEX supplement, the average conversion rates for the two preparations were 8.3% and 9.7%, respectively. Statistically, results from each preparation were equivalent.

“We show that following administration of glucoraphanin in a commercially prepared dietary supplement to a small number of human volunteers, the volunteers had equivalent output of sulforaphane metabolites in their urine to that which they produced when given an equimolar dose of glucoraphanin in a simple boiled and lyophilized extract of broccoli sprouts,”​ wrote the researchers.

“Furthermore, when either broccoli sprouts or seeds are administered directly to subjects without prior extraction and consequent inactivation of endogenous myrosinase, regardless of the delivery matrix or dose, the sulforaphane in those preparations is 3- to 4-fold more bioavailable than sulforaphane from glucoraphanin delivered without active plant myrosinase. ​

“These data expand upon earlier reports of inter- and intra-individual variability, when glucoraphanin was delivered in either teas, juices, or gelatin capsules, and they confirm that a variety of delivery matrices may be equally suitable for glucoraphanin supplementation (e.g. fruit juices, water, or various types of capsules and tablets).”  ​

Source: PLoS One​​
Published online, doi: 10.1371/journal.pone.0140963
“Sulforaphane Bioavailability from Glucoraphanin-Rich Broccoli: Control by Active Endogenous Myrosinase”​
Authors: J.W. Fahey, et al.