It’s estimated that 17 million Americans have type 2 diabetes , a number that researchers say is expected to increase dramatically due to the growing rates of obesity . Research has shown that you can lower your risk of developing type 2 diabetes by maintaining a healthy weight and being physically active.

Limited research has also suggested that coffee consumption may be associated with a reduced risk of developing type 2 diabetes. It’s an area that has not been thoroughly investigated, but could have important public health implications given coffee’s worldwide popularity and the increasing prevalence of type 2 diabetes.

A new study, published in the March 10, 2004 issue of the Journal of the American Medical Association , suggests that the more coffee you drink, the lower your risk of type 2 diabetes. Researchers are still not sure, however, why coffee appears to reduce diabetes risk.

About the Study

The researchers combined the data from three of their previous studies, all conducted in Finland, where coffee consumption is the highest in the world. A total of 6974 men and 7655 women aged 35 to 64 years, without a history of stroke, coronary heart disease, or diabetes at the start of the study, were included in this analysis.

The researchers recorded the number of new cases of diabetes among the participants over an average 12-year follow-up period. They also looked at a variety of lifestyle factors, including physical activity, smoking habits, alcohol consumption, socioeconomic status, and education. Coffee consumption was classified as: 0–2, 3–4, 5–6, 7–9, or 10 or more cups per day. Tea consumption was also examined, but only a few people reported drinking tea.

The researchers then calculated the likelihood of developing diabetes based on the amount of coffee consumed.

The Findings

The risk of developing diabetes decreased as the amount of daily coffee consumed increased. Compared to those who drank the fewest cups of coffee a day,

  • Women who drank 3–4 cups a day had a 29% lower risk of diabetes, while those who drank 10 or more cups a day had a 79% lower risk.
  • Men who drank 3–4 cups a day had a 27% lower risk of diabetes, and those who drank 10 or more cups a day had a 55% lower risk.

The risk of diabetes did not differ between non-coffee drinkers and those who drank only 1–2 cups per day. Additionally, men who drank coffee the old-fashioned way, pot-boiled, had a 2.9 times higher risk of developing diabetes compared with men who drank filtered coffee.

A limitation of this study is that the researchers did not measure other aspects of the diet that may have affected diabetes outcome, such as fiber, fat, and calorie intake. Also, this study was done on Finnish men and women, a predominantly white population. Future research should look at a wider array of the world’s population, especially since ethnicity plays a role in diabetes risk.

How Does This Affect You?

Despite the study’s weaknesses, its findings do provide further evidence that coffee consumption may help prevent diabetes. Specifically, this study suggests that the more coffee you drink, the lower your risk of developing diabetes.

What this study does not tell us, however, is what component of coffee is responsible for lowering diabetes risk. More research is needed to know whether similar beverages, such as tea and decaffeinated coffee, have the same beneficial effect.

It should be noted that while upping daily coffee intake may be an option for some, it’s not for everyone. A cup of filtered coffee has about 135 milligrams of caffeine. Some people experience “coffee jitters” or insomnia from too much caffeine. And those accustomed to regular doses of caffeine can experience headaches and fatigue due to “caffeine withdrawal” when they stray from their usual intake pattern.

Additionally, consuming high amounts of caffeine may be associated with adverse health effects for certain individuals, including those who are pregnant. The American Heart Association states that more research is needed to determine whether heavy coffee drinking is associated with heart disease. And, this study says nothing about the health benefits of drinking coffee in individuals who already have diabetes.

Although increasing your coffee habit to 10 or more cups a day is probably not justified, apparently you need not feel guilty about drinking a moderate amount. Still, when it comes to preventing diabetes, don’t ignore the many established ways to lower your risk:

  • Regular exercise
  • Low fat and calorie intake
  • Weight loss if necessary