135 grapes a day could help lower blood pressure and minimise risk of heart attack
Daily Mail Reporter
Last updated at 10:38 AM on 29th October 2008
Grapes helped lower blood pressure and improve heart function in lab
rats fed an otherwise salty diet, U.S. researchers have said.
The findings, published in the Journal of Gerontology: Biological Sciences, may help people with high blood pressure, they said.
findings support our theory that something within the grapes themselves
has a direct impact on cardiovascular risk, beyond the simple blood
pressure-lowering impact that we already know can come from a diet rich
in fruits and vegetables,' said Mitchell Seymour of the
Cardioprotection Research Laboratory at the University of Michigan.
The research showed that rats on a high-salt diet had less cardiovascular risk when they ate grape powder
a study sponsored in part by California grape producers, Seymour and
colleagues examined the effects of ordinary grapes on rats that develop
high blood pressure when fed a salty diet.
Some of the rats
ate a diet containing a powder from red, green and purple table grapes
and a high-salt diet. Others were fed the grape powder and a low-salt
diet. The powder, which contained the same nutrients in fresh grapes,
allowed the scientists to measure the rats' intake carefully.
18 weeks, the rats that ate the grape-enriched diet had lower blood
pressure, better heart function, reduced inflammation throughout their
bodies, and fewer signs of heart muscle damage than rats that ate a
salty diet but no grapes.
'The inevitable downhill sequence to
hypertension and heart failure was changed by the addition of grape
powder to a high-salt diet,' Dr. Steven Bolling of the University of
Michigan, who heads up the lab, said in a statement.
said he thinks flavonoids, beneficial chemicals found in grapes, green
tea, cocoa and and tomatoes, could be having an effect on blood
pressure. Flavonoids have been shown in other studies to have
Food producers are keen to show the
health benefits of their products. Studies sponsored by chocolate
makers, almond and walnut producers have shown various heart benefits,
including reducing inflammation in blood vessels and lowering the risk
of heart attacks and stroke.
Grape powder comprised about
three percent of the rats' diet. For humans, that would be about nine
servings of grapes a day. One serving is about 15 grapes.
California Table Grape Commission provided financial support for the
study and supplied the grape powder. Other sponsors included the
National Heart, Lung and Blood Institute, part of the National
Institutes of Health.
High blood pressure, also known as hypertension, can lead to heart attack, heart failure, stroke and kidney failure.