Veggie Diet May Lower High Blood
Pressure
By Karen Pallarito
January 21, 2005
Blood thickness and body weight improve on plant-based
regimen, study finds.
Vegetarians tend to have lower blood pressure than
the general population, but it hasn't been clear whether
their diet or their lifestyle guards them against hypertension.
A new review of previously published studies claims
that diet provides the protection.
"It's the diet itself, and it is clearly the diet
of choice for people who want to get their blood pressure
under control," said Dr. Neal D. Barnard, president
and founder of the Physicians Committee for Responsible
Medicine and co-author of the report, which appears
in the January issue of Nutrition Reviews.
Barnard, a nutritionist and author of the book Breaking
the Food Seduction: The Hidden Reasons Behind Food Cravings
and Seven Steps to End Them Naturally, concluded that
a person who suffers from hypertension and has yet to
switch to a vegetarian diet is "really trying to
fight their condition with one arm tied behind their
back."
About 65 million American adults have high blood pressure,
according to the National Heart, Lung, and Blood Institute.
Hypertension is often called the "silent killer"
because it usually has no symptoms but leads to increased
risk for heart disease, congestive heart failure, stroke
and kidney failure.
Barnard and committee nutritionist Susan Berkow analyzed
80 scientific studies, including observational studies
of individuals on vegetarian diets compared with non-vegetarians
and randomized, controlled trials in which outcomes
of people who switch to a plant-based diet were compared
with control subjects.
"The purpose of our review was to bring together
what is known about the effect of the diet, but also
what we know about the mechanism and try to explain
why this occurs," Barnard explained.
Some of the best observational data, according to the
report, come from studies involving Seventh-Day Adventists,
who advocate an alcohol-free, tobacco-free, vegetarian
lifestyle. About 50 percent of Adventists follow a lacto-ovo-vegetarian
diet, which includes dairy products and eggs, the authors
noted.
One study involving California Adventists found that
vegetarians have about half the prevalence of hypertension
compared to non-vegetarian Adventists. When hypertensives
were defined as those taking medication intended to
reduce their blood pressure, a nearly threefold difference
in the prevalence of hypertension was seen between the
groups.
Overall, the randomized controlled trials included
in the review found that blood pressure is lowered when
animal products were replaced with vegetable products
in both people with normal blood pressure and those
who are hypertensive.
To understand the blood-pressure-lowering effects of
a plant-based diet, the authors examined changes in
body weight and intake of specific food groups and nutrients.
Studies show that vegetarians tend to be slimmer, on
average, which may help explain their lower incidence
of hypertension. A vegetarian diet also is significantly
lower in saturated fat, reducing the viscosity, or thickness,
of the blood.
Blood becomes "less like oil, more like water,"
Barnard explained.
And because vegetarian diets are generally high in
fruits and vegetables, people who follow this diet consume
more potassium than those who eat a diet of meat and
vegetables. The analysis cites two reviews involving
a total of 52 randomized clinical trials showing potassium
supplementation significantly lowered blood pressure
in people with normal and elevated blood pressure.
There are those who disagree with the finding, however.
Dr. Lawrence J. Appel, a nutrition specialist at the
Johns Hopkins Bloomberg School of Public Health, said
the paper fails to establish a clear cause-and-effect
relationship between consuming a plant-based diet and
lowering one's blood pressure.
"It's a good review, but there are still unanswered
questions," he said.
He also noted that very few clinical trials have been
conducted, and that those that have been done are small
and not tightly controlled. Much of the data is observational.
So, he said, it remains unclear whether a vegetarian
diet alone is responsible for lowering blood pressure
or whether some aspect of a vegetarian regimen -- such
as eating lots of fruits and vegetables rich in potassium
and fiber while maintaining a desirable body weight
-- could have the same effect.
And then there there is the fact that not everyone
who has high blood pressure eats poorly or is overweight;
genetic factors significantly influence a person's risk
for hypertension.
Still, Barnard insists a vegetarian diet is healthy
for everyone, whether or not they have high blood pressure.
He offers this caveat for people taking blood pressure
medication: "Don't throw your medication in the
trash." High blood pressure is a serious medical
condition requiring immediate medical attention. Even
if you switch to a vegetarian diet to trim down, you
won't lose the weight overnight, he said. It could take
more than a year for a person who is 60 pounds overweight
to drop that excess baggage.
Barnard hopes the review will prompt more doctors to
recommend a vegetarian diet. Many are reluctant to do
because they fear that patients won't stick with it,
but there's no reason to believe patients would be less
likely to go vegetarian than to comply with other diets,
he said.
"They may not hit the mark 100 percent, but they'd
do much better if a doctor recommended it," he
said.
Barnard's group, the physicians committee, is a Washington,
D.C.-based nonprofit that promotes good nutrition, opposes
unethical human experimentation and advocates alternatives
to animal research.
Source:http://drkoop.com
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