Dark Chocolate May Sweeten the Way to
Health
posted July 26, 2005
By Steven Reinberg, HealthDay Reporter
Daily dose lowered blood pressure, improved insulin sensitivity, study showed.
If it tastes
good it must be bad, so the saying goes, but delicious dark chocolate may be the
exception to the rule.
In addition to all the pleasurable
sensations associated with the sweet, it may also help lower blood pressure by
an average of 10 percent while improving the body's sensitivity to insulin,
researchers report.
However, this benefit applies only to
dark chocolate, which is rich in flavonoids -- the same antioxidant compounds
found in fruits, vegetables and whole grains that are known to help lower blood
pressure, according to the report in the July 18 online edition of
Hypertension.
"It turns out that chocolate is not only
a pleasurable food, but it fits in quite nicely with the other healthy
recommendations," said coauthor Jeffrey B. Blumberg, a professor of nutrition
and a senior scientist at the Jean Mayer USDA Human Nutrition Research Center on
Aging at Tufts University. "We found that three ounces of dark chocolate per day
over several weeks reduced blood pressure in patients with essential
hypertension and also seemed to provide a benefit on their insulin sensitivity,"
he added.
In their study, Blumberg's team had 10
men and 10 women eat 3.5 ounces of dark chocolate every day for 15 days. All of
these people had high blood pressure and none were taking blood pressure
medications.
First, the researchers had five of the
men and five of the women eat dark chocolate while the others ate white
chocolate, which contains no flavonoids. Then after another week of no
chocolate, the groups "crossed over" and ate the other chocolate.
In the 15 days they were eating dark
chocolate, individuals displayed an average 11.9 mm Hg drop in their systolic
blood pressure (the top number in a blood pressure reading) and a 8.5 mm Hg drop
in diastolic blood pressure (the lower number). However, there was no drop in
blood pressure when they ate flavonoid-free white chocolate, the researchers
found.
Given these results, Blumberg believes
that dark chocolate can be good for you. "Dark chocolate can be included as part
of a healthful diet in patients who have hypertension," he said.
However, he cautioned that you can't
just add it on top of your diet. "It's still a high-calorie food. You don't want
to have excess calories or put on weight if you have hypertension," Blumberg
said. "But as part of a healthful diet, it is something that you can enjoy and
not feel you are violating the principles of a healthful diet."
Blumberg thinks that being able to enjoy
some chocolate can also make it easier to stay on a healthy diet that is rich in
fruits, vegetables and whole grains.
One expert sees this study as part of a
body of evidence that shows that chocolate is good for us. "Dark chocolate may
be health-promoting," said Dr. David L. Katz, an associate clinical professor of
public health and director of the Prevention Research Center at Yale University
School of Medicine.
Katz, who is doing his own research into
the benefits of chocolate, noted that chocolate is rich in not only
antioxidants, but also magnesium and fiber. "The predominant saturated fat in
dark chocolate, stearic acid, does not raise cholesterol or harm blood vessels,"
he added.
"Milk chocolate and white chocolate do
not offer any known health benefits, and provide more calories, sugar, and
potentially harmful oils than dark chocolate," Katz said, but "dark chocolate
may well prove to be health food."
According to Katz, there are many
unanswered questions about chocolate: What is the optimal dose of dark
chocolate? How high does the cocoa content need to be to offer health benefits?
Who in the population stands to benefit from eating dark chocolate? Are the
benefits of liquid cocoa and solid chocolate the same? Can people eat chocolate
without gaining weight?
"These answers, and others, will come in
time," Katz said. "For now, it's clear that not all chocolate is created equal.
But it's delicious to think that indulgence and health may both reside beneath
the same wrapper."
Another expert is more cautious. Without
more definitive data on whether chocolate promotes weight gain that might
outweigh its benefits, Dr. Jeffrey Mechanick, the director of the Metabolic
Support Service at Mount Sinai School of Medicine, is hesitant to recommend it
as a health food. "I would never tell a heart patient or a diabetic to eat more
dark chocolate," he said.
For patients who do not have these
health problems, Mechanick is more lenient. "Having a treat every once in a
while is fine," he said. "My preference is that you have dark chocolate, because
it's looking like maybe dark chocolate may have some benefit. But there are no
data to support that it's truly beneficial. It's still unproven that it's
beneficial and there could be risks involved."
Mechanick also warned that the data
about the benefits of dark chocolate should not mean replacing other high blood
pressure therapy with chocolate. "Chocolate is not an alternative to traditional
lifestyle changes or to taking medications to reduce risk of heart disease or to
treat diabetes," he said.
Sources: MSN Health and Fitness: HealthDay: Jeffrey B.
Blumberg, Ph.D., professor of nutrition, senior scientist, Jean Mayer USDA
Human Nutrition Research Center on Aging, Tufts University, Boston, Mass.;
David L. Katz, M.D., M.P.H., associate clinical professor of public health,
director, Prevention Research Center, Yale University School of Medicine, New
Haven, Conn.; Jeffrey Mechanick, M.D., director, Metabolic Support Service,
Mount Sinai School of Medicine, New York, N.Y.; July 18, 2005, online edition
Hypertension: Journal of the American Heart Association.
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