Coffee, Lower Type 2 Diabetes Risk Tied
But Researchers Aren't Ready to Recommend Coffee for Diabetes Prevention
July 5, 2005 --
But don't count on a daily jolt of java to fend off diabetes just yet.
The researchers reporting the finding aren't advising coffee as a diabetes
They say they found support for the idea that "habitual coffee
consumption is associated with a substantially lower risk of type 2
However, more studies are needed, they write in The Journal of the
American Medical Association.
Grounds for Research
One of the researchers was Rob M. van Dam, PhD. He works in the nutrition
department at Harvard School of Public Health.
He and his colleagues didn't do a new experiment. Instead, they reviewed 15
past studies of coffee and type 2 diabetes.
Nine studies were done over a long time -- six to 20 years. They included a
combined total of more than 193,000 people in the U.S. and Europe.
People who drank the most coffee had the lowest risk of type 2 diabetes.
They downed at least six or seven cups of coffee per day. They were 35% less
likely to develop type 2 diabetes as those who drank less than two cups of
Those who drank four to six cups per day had a 28% lower risk of type 2
diabetes, compared with people who drank the least coffee, say the
Similar patterns were seen in six other studies. Those were one-time-only
checks; they didn't track diabetes risk over time. More than 17,000 people took
part in those projects.
Filtered, Instant, Decaf Brews
Been in a coffee shop lately? If so, you've seen the array of coffee
If coffee has some advantage against diabetes, does it matter what kind you
The findings mainly reflect consumption of drip-filtered coffee. The studies
didn't have as many drinkers of instant or unfiltered coffees, say the
What about decaf coffee? The European studies didn't distinguish between
But decaf coffee was associated with lower type 2 diabetes risk in two U.S.
studies, say the researchers.
Milk & Sugar
Do milk and sugar make a difference?
A Swedish study tracked insulin sensitivity when milk, cream, or sugar was
added to coffee or tea.
Insulin is a hormone made by the body to control blood sugar.
In that study, insulin sensitivity dropped when sugar was added to coffee or
tea. Insulin sensitivity didn't change when only milk or cream was added, say
"For most people, the amount of sugar and milk added to coffee is small
compared to other food sources," say van Dam and colleagues.
Pattern, Not Proof
Coffee wasn't directly tested for diabetes prevention. No one was asked to
change their coffee consumption.
The coffee drinkers weren't healthier. "Higher coffee consumption was
generally associated with a less healthy lifestyle," say the
Future work should examine coffee's key ingredients, say van Dam and
"Currently, it is premature to recommend increasing coffee consumption
as a public health strategy to prevent type 2 diabetes," they write.
should also be considered."
A study reported by WebMD showed that regular coffee drinkers had more
stiffness to major blood vessels compared with noncoffee drinkers. Decreased
elasticity of major blood vessels is a risk factor for developing heart disease
including heart attack and stroke. Heart disease is a leading killer in the