Can Coffee Keep Diabetes at Bay?

Multiple cups of coffee a day might be enough to bring on insomnia, or at least make you feel wired and jittery, but it could also have a positive effect.

Drinking four cups a day cuts a woman's risk of getting type 2 diabetes by more than 50 percent, according to a new study reported by

Researchers at the University of California, Los Angeles examined the medical histories of 359 diabetic women and 359 non-diabetic women over a period of 10 years. They also looked at the two groups' coffee-drinking habits, using information from the Women's Health Study, run by the National Institutes of Health. The study was published in the journal Diabetes.

The researchers found that the women who consumed four cups of caffeinated coffee daily had higher blood levels of a substance called SHBG (sex hormone-binding globulin, which regulates the levels of sex hormones in the blood). Increased levels of SHBG are associated with a lower risk of getting type 2 diabetes. The four-cup-a-day coffee consumers were 56 percent less likely to get type 2 diabetes as the coffee abstainers.

It's not the first time coffee's been linked to a decreased risk of developing type 2 diabetes. Past research had linked coffee drinking with a reduced risk of developing not just type 2 diabetes, but also liver cancer, gallstones, Parkinson's disease, and even Alzheimer's disease, according to Diabetes Forecast magazine. Those findings are promising but inconclusive, according to Rob van Dam, Ph. D., assistant professor in the Department of Nutrition at the Harvard School of Public Health, as reported in Diabetes Forecast.

Spyros Mezitis, MD, an endocrinologist at Lenox Hill Hospital in New York City, calls the study interesting. "But at this point, I would like to see larger studies and more carefully done trials where they look at all the other risk factors for diabetes in these patients, such as being overweight or being a smoker," he says. He said he'll still advise his patients to limit themselves to two cups of coffee per day.

One downside of drinking coffee is that it can make you feel jittery and has been associated with high blood pressure, notes Diabetes Forecast. In some people, it causes insomnia.

"Sleep deprivation is linked to obesity, which is linked to diabetes," says Adee Rasabi, RD, CDN, CDE, senior dietitian of the Ambulatory Care Network at New York Presbyterian Hospital in New York City. "Getting seven or eight hours of sleep is just as important as what you eat during the day."

If coffee keeps you up and you don't get enough sleep, your body tends to crave sugary foods, Rasabi adds. Also, while coffee itself doesn't have calories, it's all too easy to stir in the cream, whole milk, sugar, and syrups, she says. "People like coffee with all the bells and whistles," Rasabi says. "And what you put into coffee can really rack up the calories and fat content."

If you like milk in coffee, choose skim. And since coffee is a diuretic, make sure you stay properly hydrated with lots of water. And, Rasabi says, keep in mind that there's another way to reduce your risk of type 2 diabetes. "My suggestion is to focus on making dietary and lifestyle modifications as a way to reduce your risk," Rasabi says.


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Goto, Atsushi, Song, Yiqing, Manson, JoAnn, Buring, Julie, Liu, Simin, "Coffee and Caffeine Consumption in Relation to Sex Hormone-Binding Globulin and Risk of Type 2 Diabetes in Postmenopausal Women." January 2011. Diabetes.