Scientific research may soon help coffee shed some of its
image as an unhealthy drink. Or at least that's what the big companies that
sell it are hoping it will do.
With tens of millions of cups of coffee jolting Americans awake each day, a
bevy of research is under way trying to tease out the health advantages -- and
disadvantages -- of the nation's coffee fixation.
Coffee's image took a hit in 1982 when a major study concluded that frequent
use increased the risk of pancreatic cancer. Since then, coffee companies have
funded more and more research seeking to show the opposite: that coffee may
actually have some health benefits.
While studies are backing up some of the health warnings, a growing body of
research is suggesting that daily coffee consumption may lower the risk of type
According to Lenore Arab, PhD, a nutritional epidemiologist at UCLA, other
studies suggest less conclusively that coffee could help lower the risk of
liver cancer, Parkinson's disease, and possibly colon cancer. And Arab says
other research suggests high coffee intake by pregnant women can put their
children at risk of leukemia.
Arab spoke at the Federation of American Societies of Experimental Biology
annual meeting in Washington. He says two major studies, one from Canada and
the other from Uruguay, showed a 60% to 70% increased risk of bladder cancer
among regular coffee drinkers.
"Cancer -- the total picture -- is somewhat mixed," Arab says.
"Basically, it's neutral," says Dan Steffen, a scientific public
relations official with Kraft Foods.
But coffee companies are most excited about evidence suggesting coffee could
help prevent diabetes.
Rob M. van Dam, PhD, a Harvard researcher, says his 2005 analysis of eight
major studies concluded that adults who consume six to seven cups of coffee per
day lower their risk of diabetes by one-third over those who drink two cups per
Van Dam says a study last year showed two or three cups per day lowered
women's diabetes risk by 13%. Four or more cups per day cut the risk by more
At least seven other studies suggest similar benefits, says van Dam.
The findings are puzzling to researchers because several of caffeine's
individual components, including caffeine, raise cholesterol and lower sugar
metabolism. That should make them worse for diabetes, not better.
"We're not talking about caffeine," van Dam says. "It really
seems to be the coffee, rather than the caffeine."
Stronger Data Needed
Van Dam and other researchers warn that almost all of their evidence comes
from population- based studies, not the kind of controlled, randomized clinical
trials that can better determine true cause-and-effect relationships.
Coffee has thousands of components, most of which are not well studied. It's
not even clear that European studies on the benefits of a few daily cups of
coffee offer any good conclusions for America's legions of consumers.
"What the heck is a cup? Is it a Starbuck's 20-ouncer, or is it a
5-ounce teacup?" says James Coughlin, PhD, a private toxicology consultant
and one-time coffee industry scientist.
Van Dam also stresses that he does not recommend coffee as a diabetes
prevention aid. "If you want to lower the risk of diabetes, you'd better
focus on whole-grain consumption, physical activity, and weight loss," he
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By Todd Zwillich
Reviewed by Louise Chang
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