Three Cups of Coffee a Day Could Keep Type 2 Diabetes Away

Coffee lovers keep getting tossed between studies showing the side effects of the beverage and the health benefit. Another new study can be added to the benefits of coffee -- this time, the benefits of coffee in protecting against type 2 diabetes. 

Over the last several years, studies have consistently shown a link between drinking coffee and having a lower risk of developing type 2 diabetes.

A new analysis from a team in Sweden finally puts a number with that reduced risk. People who report moderate to heavy coffee drinking have a 25 to 29 percent lower risk of developing type 2 diabetes compared to those who don't drink it at all. 

The type 2 diabetes problem

In the United States alone, roughly 29.1 million people live with type 2 diabetes. More than one in every 10 adults aged 20 or over in the US have diabetes. And in senior adults (those over 65 years old), that figure grows to more than one in four. 

Type 2 diabetes isn't just a prevalent problem; it's an expensive one as well. Diagnosed type 2 diabetes cases in the US run a cost of $245 billion in 2012, and that number has increased in recent years. 

Correlating coffee and type 2 diabetes

The global study was conducted by two researchers from the Karolinska Institutet in Sweden and can be found in Nutrition Reviews. The findings reflected a comprehensive look at 30 major studies comparing coffee and diabetes. In total, the data included over 1.18 million participants. 

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“The inverse association between coffee consumption and type 2 diabetes was shown in both men and women,” said Dr. Carlstrom a professor of physiology and pharmacology in Sweden.

The study noted there are a number of relevant compounds in coffee, most of which could provide benefits to drinkers: caffeine, hydroxycinnamic acids notably chlorogenic acid, trigonelline, diterpenes eg cafestol and kahweol, and caffeic acid. 

Trying to stay away from all that caffeine? No worries; the researchers discovered the effects happened with both caffeinated and decaffeinated coffee. Thus, the benefits stem from something in the bean rather than the caffeine. 

“Results for both caffeinated and decaffeinated coffee were available in 10 studies. Comparing the highest versus the lowest category, both caffeinated coffee consumption (RR [risk ratio] 0.73) and decaffeinated coffee consumption (RR, 0.80) were inversely associated with risk of T2D,” they wrote. "The risk of T2D decreased, respectively, by 7% and 6% per cup-per-day increment of caffeinated and decaffeinated coffee consumption.”

Other health benefits to coffee

Like eggs and dairy, coffee is one of those headline-making food/beverage items that people can't stop debating. A few years ago, studies claimed coffee would lead to extensive sleep impairment or more cases of cancer. 

However, after further investigation, the World Health Organization removed coffee from its list of possible carcinogens. And since then, the evidence has been stacking pretty consistently in favor of the dark beverage. 

In addition to type 2 diabetes, coffee can help stave off other diseases like cardiovascular issues, Parkinson's disease, liver cancer, gout, and cirrhosis. 

Harvard Health Publishing faculty editor Robert Shmerling said it still remains relatively impossible to pinpoint exactly what in coffee leads to these benefits. 

"One factor, of course, could be the caffeine, but that can be hard to sort out from the research because many studies do not distinguish whether the coffee is caffeinated or decaffeinated," he noted.