Broccoli May Bolster Body's Defenses Against Heart Disease and Stroke
Posted May 03, 2004
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FOR IMMEDIATE RELEASE - May 3rd, 2004 2004-05-01-OTHER
Broccoli May Bolster Body's Defenses Against Heart Disease and Stroke
Compounds in broccoli may supercharge the body's ability to mop up free
radicals and so protect against high blood pressure, stroke and heart
disease, according to research led by University of Saskatchewan health
scientist Bernhard Juurlink and recently published in the Proceedings of the
National Academy of Sciences (PNAS) in the U.S.
"Nearly all the studies to date have focused on the protective effects of
these substances against cancer," said Juurlink, head of the U of S
department of anatomy and cell biology. "This study is the first to show
that broccoli sprouts rich in these compounds, through raising the
antioxidant and thereby the anti-inflammatory capacities of cells, can
correct major dysfunctions such as hypertension and stroke."
The research team is exploring oxidative stress which occurs when free
radical production outstrips the body's ability to neutralize it. Free
radicals are unstable chemical byproducts of the body's normal metabolism
which damage essential cell molecules in a manner similar to the rusting of
iron. This damage leads to cardiovascular disease and other ailments.
Tissues have a variety of defenses to prevent this "rusting" - systems that
Juurlink and his team found can be bolstered by eating foods rich in
chemicals called phase 2 protein inducers. One such inducer, glucoraphanin
(Grn), is found in high levels in broccoli sprouts (baby broccoli plants
with a pleasant, tangy flavor).
"Phase 2 inducers promote the production of phase 2 proteins," Juurlink
says. "These proteins either promote scavenging of oxidants or decrease the
chance of these oxidants being formed in the first place. The result is a
huge multiplier effect. One phase 2 protein inducer likely has the same
effect as thousands of typical anti-oxidant molecules."
The researchers fed broccoli sprouts to two groups of rats that were prone
to high blood pressure and stroke. One group received sprouts high in Grn,
while the other group received a Grn-poor variety. At the end of 14 weeks,
the rats on the high-Grn diet displayed more vigorous antioxidant defense
mechanisms. They also had lower blood pressure and decreased inflammation of
the heart and kidney.
The study suggests a modest change in diet could have profound health
benefits. Juurlink says if humans respond the same way as the test animals,
one or two grams of fresh broccoli sprouts per day per kilo of body weight
would do the trick. This works out to 70 to 140 grams (roughly two to four
ounces) for a 70-kilogram person, or a smallish serving with supper every
day. The team hopes to repeat the study in human subjects to confirm the
beneficial effects.
Anti-cancer effects of the sprouts, documented in a study published in 2002
by a team at Johns Hopkins University School of Medicine in Maryland, appear
to be due to the same enhanced antioxidant effect. The 2002 study also
showed a powerful antibacterial effect against Helicobacter pylori, an
organism known to cause stomach ulcers.
Why sprouts? They have much higher concentrations of Grn than mature
broccoli. Juurlink estimates you would need to eat 20 to 50 times as much of
the mature plant to get the same benefits.
If broccoli sprouts are hard to come by in your supermarket, you can also
get phase 2 protein inducers into your system with other foods. Some
examples are flax seed, soy products, kale - and for dessert, raspberries,
blackberries, strawberries, blueberries and cranberries.
Funding for the study was provided by the Saskatchewan Agricultural
Development Fund. Other researchers on the team included Lily Wu
(pharmacology), Hossein Noyan Ashraf (post-doctoral fellow in anatomy and
cell biology), Marina Facci (graduate student), Rui Wang (physiology),
Phylis Paterson (pharmacy and nutrition), and Alison Ferrie (National
Research Council's Plant Biotechnology Institute).
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For more information, contact:
Bernhard Juurlink
Department of Anatomy and Cell Biology
College of Medicine
University of Saskatchewan
(306) 966-4083
bernhard.juurlink@usask.ca
Michael Robin
Research Communications
University of Saskatchewan
Tel: (306) 966-2427
michael.robin@usask.ca
www.usask.ca/research
