Bioavailability and Kinetics of Sulforaphane in Humans After Consumption of Cooked Versus Raw Broccoli

Bioavailability and kinetics of sulforaphane in humans after consumption of cooked versus raw broccoli.

J Agric Food Chem. 2008 Nov 26;56(22):10505-9.

Vermeulen M, Klöpping-Ketelaars IW, van den Berg R, Vaes WH.

TNO Quality of Life, AJ Zeist, The Netherlands.

The aim of this study was to determine the bioavailability and kinetics of the supposed anticarcinogen sulforaphane, the hydrolysis product of glucoraphanin, from raw and cooked broccoli. Eight men consumed 200 g of crushed broccoli, raw or cooked, with a warm meal in a randomized, free-living, open cross-over trial. Higher amounts of sulforaphane were found in the blood and urine when broccoli was eaten raw (bioavailability of 37%) versus cooked (3.4%, p ) 0.002). Absorption of sulforaphane was delayed when cooked broccoli was consumed (peak plasma time ) 6 h) versus raw broccoli (1.6 h, p ) 0.001). Excretion half-lives were comparable, 2.6 and 2.4 h on average, for raw and cooked broccoli, respectively (p ) 0.5). This study gives complete kinetic data and shows that consumption of raw broccoli results in faster absorption, higher bioavailability, and higher peak plasma amounts of sulforaphane, compared to cooked broccoli.


Note from ISS:  Several crucifer sprouts including broccoli sprouts are currently the most potent natural source of sulforaphane known.  They often produce 10 to 100 times the amount of sulforaphane as their corresponding mature vegetables. ("Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens.", Proc Natl Acad Sci U S A 1997 Sep 16;94(19):10367-72.)

Broccoli sprouts are consumed raw whereas a very large percentage of mature broccoli is cooked.