Here's one reason why you can go ahead and indulge yourself in another round of coffee today: Drinking extra coffee a day can apparently reduce your risks of developing diabetes, a disabling and potentially fatal disease that affects at least 8 percent of America's population.

In a new study published in the journal Diabetologia Thursday, researchers from the Department of Nutrition at Harvard University's School of Public Health studied the link between changes in coffee intake and risks of developing diabetes by analyzing the health, lifestyle and diet of over 100,000 individuals in a span of 20 years using data from three large observational studies.

The researchers found that the participants who increased their coffee intake by more than one cup a day lowered their risks for Type 2 diabetes by 11 percent compared to those who did not make changes to their coffee consumption. Those who reduced their coffee intake by one cup or more a day, on the other hand, increased their risks by 17 percent compared to those who did not make changes to their coffee drinking habits.

For individuals who drink three or more cups of coffee a day and did not adjust their coffee drinking habits, their risks for diabetes is 37 percent lower than those who drink one or less than a cup of coffee per day. The researchers also noted that the results appear to be independent of other factors such as the initial coffee intake of the participants and changes in their diet and lifestyle.

Study author Shilpa Bhupathiraju, a research fellow at the Harvard School of Public Health, said that individuals with high risks for diabetes may want to drink an extra cup or 8 ounces of coffee a day. The coffee Bhupathiraju and his colleagues discussed about in their study though are not the coffee blended drinks typically available at Starbucks but plain black coffee or perhaps with a little milk and sugar.

"Changes in coffee consumption habit appear to affect diabetes risk in a relatively short amount of time," the researchers concluded. "Our findings confirm those of prospective studies that higher coffee consumption is associated with a lower type 2 diabetes risk, and provide novel evidence that changes in coffee consumption habit is related to diabetes risk."

The study [downloadable zip file] entitled "Changes in coffee intake and subsequent risk of type 2 diabetes:three large cohorts of US men and women" is published in the journal Diabetolgia.