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A Green Giant?
Souped-up
broccoli may be new cancer weapon
By Liz Lynch
HealthSCOUT Reporter
THURSDAY, June 1 (HealthSCOUT) -- Now you can ditch that boring old regular
broccoli in favor of a plate of superbroccoli. Mind you, the new stuff
tastes the same as the old stuff, so for those who dislike broccoli, this is not
exciting news. But this newly bred broccoli could be a potent weapon in cancer
prevention.
Scientists at the Institute for Food Research in Norwich, England,
crossed a wild Sicilian strain of broccoli with an ordinary variety to produce
the new broccoli. They describe it in the current issue of New Scientist.
It looks and tastes the same as your basic broccoli, but the new variety contains
10 times as much sulforaphane as its ordinary cousin, says Gary Williamson,
head of the superbroccoli research team. Sulforaphane is one of a number of
plant byproducts thought to help neutralize cancer-causing substances in the
body. Apparently, when released in the stomach, sulforaphane steps up production
of cancer-fighting enzymes.
Just how this happens, however, is still being untangled by researchers. In a
study set to begin later this year, Williamson plans to further examine the
process by having people eat either regular broccoli or superbroccoli and then
comparing the effects. He expects that to indicate whether the superbroccoli
boosts concentrations of anti-cancer enzymes in the blood even higher than
regular broccoli does.
Sulforaphane is derived from a substance called glucoraphanin, a "secondary
metabolite" of the plant. "Plants don't have kidneys, so they produce
complex secondary metabolites instead," explains Elizabeth Jeffery, a
nutrition professor at the University of Illinois. "[The secondary
metabolites] play hormone-like roles in the plant or protect the plant from
noxious insects and other predators."
In cruciferous vegetables such as broccoli, several substances, including
sulforaphane, are produced from secondary metabolites. Several of these products
"have been found to be active in cancer prevention trials," Jeffery
says. Cruciferous vegetables -- a family of vegetables known for the shape of
their flowers and pods and for their strong odor -- also include cabbage,
turnips, radish and horseradish.
While glucoraphanin and its derivative, sulforaphane, can be found in a number
of vegetables, "it is in much higher concentration in broccoli than other
vegetable types," she says. Still, the amount of sulforaphane varies widely
among types of broccoli.
"Not
all broccolis are created equal," Jeffery says, "and the new product
from Britain is even more unequal." But does any of this add up to advice
on how much broccoli to eat?
Few
studies have pinpointed things that precisely, Jeffery says. In clinical tests,
people who ate 250 grams a day of cruciferous vegetables raised their levels of
anti-cancer enzymes, she says. And, she adds, "as little as two to three
servings a week was found to significantly decrease risk for prostrate cancer in
a study in the Journal of the National Cancer Institute earlier this
year.
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