In short term studies,
these finding may be contradicted, suggesting that coffee
with caffeine may
reduce the body's sensitivity to insulin and therefore pose
additional problems. However, in the Harvard study, over
100,000 men and women were followed for almost 20 years. Hu
indicated that the next step would be to try and replicate the long
term study's results. The question being of course, how many
of us have 20 years to sit around and wait to see if we should be
drinking coffee.
Coffee is Good for Men
and Women
The more
coffee the men and women drank, the more it seemed to help prevent
diabetes. The findings held true even after accounting for other
risk factors linked to diabetes, including age and weight.
For men:
- 1 to 3 cups of coffee a day
dropped the risk of diabetes in men by 7%.
- 4-5 cups a day cut the risk of
diabetes by 30%.
- 6 or more cups of coffee a day
dropped the risk of diabetes by more than 50%.
For
women:
- No effect on diabetes prevention
was seen for women who drank 1 to 3 cups a day.
- Four cups or more a day reduced
their risk of diabetes by about 30%.
- 6 cups did not seem to be any
better than four cups.
Decaf
or Regular Coffee?
Caffeine might be
coffee's best-known ingredient, but it's not the only one, Hu notes.
Coffee houses dozens of other substances that could affect disease
risk. There's magnesium, niacin, potassium, and even such
antioxidants as tocopherol.
Hu's team reasoned
they could tease out the effects of caffeine on diabetes prevention
by also looking at tea and decaf coffee.
"Decaf coffee
has the
same amount of these other substances, but less caffeine," Hu
says. "Tea has other substances and is relatively low in
caffeine."
Four or
more cups of decaf coffee a day was associated with a modest effect
on diabetes prevention. But the findings could have been due to
chance, Hu says.
Tea had
no impact on diabetes prevention, the researchers found.
The
researchers then looked at total caffeine intake from coffee, sodas,
and other foods, and found it, too, appeared to help prevent
diabetes. Men and women who consumed the most caffeine were about
25% less likely to develop diabetes compared with those who consumed
the least.
I'm a
believer in coffee
The new
findings on coffee have made a believer out of at least one former skeptic,
and a key one at that: Terry E. Graham, PhD, who performed one of
the studies showing caffeine reduces the body's ability to handle
blood sugar.
"When
the Dutch coffee study came out, I was shocked," says Graham, chairman
of human biology & nutritional sciences at the University of
Guelph in Guelph, Canada. "But now, with this second study that
shows the same thing, you start to believe it."
The
Harvard study is more thorough, he says, with more accurate data
about the participants' coffee habits over 10 to 15 years.
"Plus, they evaluated tea and decaf coffee, which the first study
didn't."
Some
clues into why the short-term and long-term studies arrive at such
different results might come soon, he says. Vanderbilt University
researchers who are studying compounds produced when coffee beans
are roasted appear to have homed in on some with disease-fighting
properties.
In the
meantime, Hu says he is not yet ready to recommend coffee to help
prevent diabetes.
"We
still need more study," he says. "But it's intriguing. And
it's not detrimental -- one thing coffee lovers don't have to worry
about."
Gourmet
coffee lovers rejoice
