We don't know, actually. But this week we saw the second large study to show that drinking a lot of regular coffee cuts the chances of getting Type II diabetes–the most common kind, affecting 17 million Americans–by about 50 percent.
advertisement
E-mail your comments or suggestions to Josh Fischman: pulse@usnews.com
This is particularly odd because doctors have, in the past, warned diabetics away from coffee. The caffeine, in a few short-term studies, interfered with the body's ability to use sugar, which is the basic problem with diabetes anyway. Plus, people tend to load their coffee with cream and sugar, two substances that can play havoc with cholesterol and blood pressure levels and heart disease risk; again, diabetics already have trouble controlling these things.
This new study looked at people over the course of 12 to 18 years. The results, reported in this week's Annals of Internal Medicine, were striking. Among the 42,000 men followed, drinking six or more cups of regular coffee per day cut their diabetes risk by 54 percent. Drinking four or five cups cut the risk by 29 percent. Last year a large Dutch study found a similar risk reduction. Among 84,000 women followed in the new study, the big coffee guzzlers cut their risk by 29 percent, and women drinking four or five cups cut their risk by a similar margin.
Obviously the relationship is stronger and clearer in men. It may be one of the few clear things about the study, because there's no simple explanation for the sex differences. It's not due to obesity, because the researchers took that into account to make sure they weren't really comparing a bunch of skinny, hyper caffeine addicts to heavier people who–simply because of their weight–carry a heightened risk of diabetes.
Gender aside, caffeine appears to make a difference. The new study found no significant protective effect among decaf drinkers. Since this study lasted longer than the previous ones, researchers speculate that while caffeine may have a negative effect at first, over time it may have a positive one. And while they're speculating, they also note that coffee has helpful substances such as antioxidants, which may kick in over time to protect cells from damage.
Given all the questions, however, this clearly isn't the time to park yourself at the Starbucks counter in the hope of warding off diabetes. Don't, in fact, park yourself at any counter. Exercise has a very strong protective effect against diabetes, as it improves the body's ability to utilize sugar. And that fact doesn't need to be qualified with a lot of mystifying speculation.
