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A cup of confusion: Is coffee healthy or not?

By Karen Collins, R.D. Special to msnbc.com

Considering all the past concern about possible health risks from drinking coffee, newer reports of coffee's
possible protective effects may leave many people confused. 

Overall, recent studies suggest that coffee (regular and decaffeinated) may offer a variety of health benefits against
diseases such as cancer and diabetes. However, coffee may not deserve a place in the same category with other
healthful foods like vegetables, fruits and whole grains.

Laboratory studies suggest that the anti-inflammatory, antioxidant compounds in coffee could help reduce risk
of cancer. Coffee also has a tendency to speed the passage of waste through the digestive tract. Potentially,
this may lessen the time that cancer-causing compounds spend in contact with the intestinal tract, which could
reduce the risk of colon cancer. Population studies, however, tend to split between coffee intake having no
effect on or reducing risk of breast and colon cancer.

Diabetes prevention
The case for coffee's ability to protect against diabetes is strengthened by several recent studies. In the
Iowa Women's Health Study, more than 28,000 women were followed for 11 years. The women who
drank four or more cups of coffee daily were about 20 percent less likely to develop diabetes.
That became a 30 to 40 percent drop among those who drank decaf coffee. 

A study in Finland linked consumption of three to six cups of coffee per day with a 25 percent lower risk
of diabetes. In both studies, benefits were seen after adjusting for other diabetes risks, such as weight, diet,
and activity level. Several studies now link moderate coffee consumption with lower risk of Type 2 diabetes.
Researchers are working to understand the potential advantage of decaf versus regular coffee and how
weight control is involved.

Potential increased risk of high blood pressure and heart disease has been one of the long-standing concerns
about coffee. Recent studies confirm that caffeine can raise blood pressure, but this effect is observed with
soft drinks, not coffee. Laboratory studies suggest that perhaps coffee's healthful compounds can counterbalance
the blood-pressure raising effects of caffeine.

In the Iowa Women's Health Study noted above, four to five cups of coffee a day were linked with a 19
percent lower risk of heart-related death. Other studies have found no effect of coffee consumption on heart
disease risk. But people should follow their doctor's advice.

Before you drink a whole pot ...
Coffee does warrant some cautions, however. Both regular and decaf coffee relax the muscle that keeps
stomach acids from rising into the throat, so those with heartburn or reflux disease (GERD) are encouraged
to avoid or strictly limit coffee. People with trouble sleeping should limit or avoid caffeinated coffee.

Studies now suggest it is unnecessary for pregnant women to completely avoid caffeinated coffee. Until the
impact of caffeine is more clearly understood, however, many experts suggest that pregnant women limit their
daily caffeine from coffee, soft drinks and other sources to about 300 mg, the equivalent of three cups of regular
coffee.

It's exciting that something as simple as drinking coffee might help lower our risk of cancer, diabetes and heart
disease. However, while brewed coffee (not freeze dried) is a concentrated source of antioxidants, it can't be a
substitute for berries, legumes, nuts, and other fruits and vegetables that provide antioxidants along with a
wide range of vitamins, protective compounds and dietary fiber.

Nutrition Notes is provided by the American Institute for Cancer Research in Washington, D.C.

© 2008 MSNBC Interactive
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