Coffee and Diabetes: What's the Link?

More than 23 million Americans suffer from diabetes--90 to 95 percent of those cases are type 2 diabetes. It's a chronic condition that occurs when your body doesn't effectively use the insulin that it makes. Insulin helps to control blood sugar levels in the body and to carry them into the cells. Diabetes can lead to other serious conditions including blindness, kidney disease and nerve damage.

In a Dutch study, researchers gave nearly 82,000 women and just under 42,000 men a questionnaire to fill out every two to four years to determine how often they drank coffee and other beverages. The survey also collected information on the participants' health condition, including type 2 diabetes mellitus. The researchers then compared the frequency with which the disease developed in several groups of people with different intakes of coffee and other caffeine-containing drinks.

The researchers discovered that participants who drank more coffee were less likely to develop type 2 diabetes mellitus, while taking into account other diabetes risk factors, such as body size. This correlation between coffee and diabetes was stronger in women than in men.

However, the study design didn't allow researchers to reach a direct coffee and diabetes prevention connection. They suggest there might be another factor that protects coffee drinkers from the disease. Also, the study did not separate regular from decaffeinated coffee and did not ask the participants about other caffeine-containing drinks they may have consumed. In the end, the researchers recommended that future research examine the role caffeine plays in sugar metabolism.

Which is exactly what another study did. The results show that while coffee may be able to ward off type 2 diabetes, caffeine poses risks if you already have the disease. Duke University researcher James D. Lane, Ph.D. and his colleagues found that when patients with type 2 diabetes took caffeine capsules their blood sugar levels were eight percent higher.

After every meal--including dinner--their blood sugar spiked higher than it did when they didn't have caffeine. "In a healthy person, glucose is metabolized within an hour or so after eating. Diabetics, however, do not metabolize glucose as efficiently," said James D. Lane, Ph.D., associate research professor in the department of psychiatry and behavioral sciences at Duke, and lead author of the study. "It appears that diabetics who consume caffeine are likely having a harder time regulating their insulin and glucose levels than those who don't take caffeine."

Although the study involved only 10 people, the findings hint that the key player in coffee and diabetes prevention may not be caffeine, but some other ingredient.

Study References

Journal Name: Annals of Internal Medicine, Vol. 140 Issue 1, pp. 1-17

Study Date: 6 January 2004

Study Name: Coffee Drinkers at Lower Risk for Type 2 Diabetes


Authors: E. Salazar-Martinez, W.C. Willett, A. Ascherio, J.E. Manson, M.F. Leitzmann, M.J. Stampfer, and F.B. Hu.


Journal Name: Diabetes Care, Vol. 27 No. 8, pp. 2047-2048

Study Date: August 2004  

Study Name: Caffeine Impairs Glucose Metabolism in Type 2 Diabetes


Authors:  James D. Lane, PHD, Christina E. Barkauskas, AB, Richard S. Surwit, PHD and Mark N. Feinglos, MD