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,"
"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
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
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.