Chopping And Cooking Affect
Garlic's Anti-Cancer
Activity
University Park, Pa. ---
Penn State researchers have
shown that microwave heating
or roasting garlic can
diminish or destroy its
anti-cancer activity -
unless the herb is chopped
or crushed, and allowed to
"stand" for at least 10
minutes before cooking.
Kun Song, doctoral candidate
in nutrition, and Dr. John
A. Milner, professor and
head of the Department of
Nutrition, conducted the
study.
The research was the first
to show that as little as
one minute of microwaving or
45 minutes of oven roasting
can completely block
garlic's ability to retard
the action of a known
cancer-causing agent in
rats. Garlic's anti-cancer
activity was retained,
however, if the herb was
first chopped or crushed and
allowed to stand for 10
minutes before being heated.
In the case of roasted whole
garlic, anti-cancer activity
was partially retained if
the top of the bulb was
sliced off prior to heating.
Song presented the results
in a poster session titled,
"Heating Blocks Garlic's
Protection Against 7,12
Dimethylbenz(a)anthrancene (DMBA)
Induced Rat Mammary DNA
Adducts," at a conference on
"Recent Advances on the
Nutritional Benefits
Accompanying the Use of
Garlic as a Supplement" at
the Marriott Newport Center,
Newport Beach, Calif.
The conference is a
continuing and distance
education service of the
Penn State College of Health
and Human Development
Department of Nutrition in
cooperation with Wakunaga of
America Co. Ltd. The
conference is supported by
Wakunaga, National Cancer
Institute and Rexall-Sundown
Inc.
In a recent interview, Song
said that the 10-minute
"standing period" after
chopping or crushing the
garlic enables an enzyme
naturally present in certain
garlic cells to come in
contact with and act on
chemicals in other cells.
Chopping or crushing the
garlic opens the cells and
enables the enzyme to start
a reaction that produces
chemicals called allyl
sulfur compounds that
possess anti-cancer
properties.
"The allyl sulfur compounds
produced from the enzyme's
reaction are critical to
garlic's anti-cancer
effects," Song noted. "If
garlic was heated or roasted
immediately after crushing,
the enzyme was de-activated
by the heating process and
garlic's anti-cancer effects
were blocked."
Song and Milner conducted
the study with rats given
garlic by intubation six
times over a two-week
period. The rats received
garlic equal to 2 percent of
their daily food ration.
After the feeding period was
over, the rats were treated
with a breast tumor inducer
called DMBA. Genetic
material (DNA) from the
rats' breast tissue then was
examined in order to count
the number of instances in
which DMBA reaction products
or metabolites had become
attached to the DNA. The
number of DMBA metabolites
binding to DNA, called DNA
adducts, was used as the
measure of cancer incidence.
Rats that received no garlic
had the highest number of
adducts. Rats given raw
garlic showed an average
decrease of 64 percent in
adduct formation compared
with rats that had received
no garlic. Rats given garlic
that had been heated for one
minute in the microwave oven
or roasted in a convention
oven for 45 minutes after
being crushed and allowed to
"stand" for 10 minutes
showed 41 percent and 21
percent reductions in adduct
formation, respectively.
Rats given heated or roasted
garlic that had not been
allowed to stand showed no
decrease in adducts compared
with non-garlic fed rats.
The study was supported by a
grant from the American
Institute of Cancer
Research.
Article Source
Contact: Barbara Hale
bah@psu.edu
814-865-9481
Penn
State
|
