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Nutrition Notes
Week of December 11, 2006

Coffee: Health Food or Simply Not a Risk?

Karen Collins, MS, RD, CDN
American Institute for Cancer Research

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.

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.

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 instant) 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.

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The American Institute for Cancer Research (AICR) offers a Nutrition Hotline online at or via phone 9 a.m. to 5 p.m. ET, MondayFriday, at 1-800-843-8114. This free service allows you to ask questions about diet, nutrition and cancer. A registered dietitian will respond to your email or call, usually within 3 business days. AICR is the only major cancer charity focusing exclusively on how the risk of cancer is reduced by healthy food and nutrition, physical activity and weight management. The Institute’s education programs help millions of Americans lower their cancer risk. AICR also supports innovative research in cancer prevention and treatment at universities, hospitals and research centers across the U.S. Over $78 million in funding has been provided. AICR is a member of the World Cancer Research Fund International.

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