The New Complete Book of Food
with laboratory rats, sulforaphane appears to increase the body’s production of phase-2
enzymes, naturally occurring substances that inactivate and help eliminate carcinogens.
At the Johns Hopkins University in Baltimore (MD), 69 percent of the rats injected with a
chemical known to cause mammary cancer developed tumors vs. only 26 percent of the rats
given the carcinogenic chemical plus sulforaphane.
In 1997, Johns Hopkins researchers discovered that broccoli seeds and three-day-old
broccoli sprouts contain a compound converted to sulforaphane when the seed and sprout
cells are crushed. Five grams of three-day-old broccoli sprouts contain as much sulforaphane
as 150 grams of mature broccoli. The sulforaphane levels in other cruciferous vegetables have
not been calculated.Adverse Effects Associated with This Food
Enlarged thyroid gland (goiter). Cruciferous vegetables, including radishes, contain goitrin,
thiocyanate, and isothiocyanate. These chemicals, known collectively as goitrogens, inhibit
the formation of thyroid hormones and cause the thyroid to enlarge in an attempt to produce
more. Goitrogens are not hazardous for healthy people who eat moderate amounts of crucif-
erous vegetables, but they may pose problems for people who have a thyroid disorder.Food/Drug Interactions
False-positive test for occult blood in the stool. The active ingredient in the guaiac slide test
for hidden blood in feces, alphaguaiaconic acid, a chemical that turns blue in the presence of
blood. Alphaguaiaconic acid also turns blue in the presence of peroxidase, a chemical that
occurs naturally in radishes. Eating radishes in the 72 hours before taking the guaiac test may
produce a false-positive result in people who do not actually have any blood in their stool.