You may wonder as you grab a mug to pour yourself a cup of “Joe” or head into your local café to order a latte…is drinking coffee harmful or helpful when it comes to diabetes? Let’s take a look at the latest information when it comes to drinking coffee and it’s impact on diabetes prevention as well as on those currently diagnosed.


What the Research Shows…Mostly Good News!


There is no shortage of research looking into coffee consumption and diabetes, namely type 2 diabetes. Being that coffee is one of the most popular beverages and is consumed by populations all over the globe, it has proved worthwhile to investigate its impact on chronic diseases and their prevention.

For many years, a multitude of studies have found that coffee drinkers are less likely to develop type 2 diabetes.  A recent meta-analysis published in Diabetes Care noted that consumption of both caffeinated and decaffeinated coffee offers a protective effect when it comes to type 2 diabetes risk. In comparison to those who do not drink any coffee, the analysis found that consuming six cups of coffee was associated with a 33 percent lower risk of developing type 2 diabetes. Other studies have shown different amounts of risk reduction, with a range between 11-60 percent.  And, the amount of coffee consumed in a day that has been indicated to be protective has varied between 2 cups to over 6 cups a day in studies.


For those who have already been diagnosed with type 2 diabetes, a recent study published this year has revealed that drinking coffee may be associated with reduced all cause and cardiovascular disease mortality, but more research is needed to solidify this conclusion.  


However, there are some conflicting studies that have shown that the caffeine in coffee can raise after meal blood sugars in people with diabetes by as much as 20 percent, namely when it was consumed with a meal containing carbohydrates.  Caffeine has the potential to lower insulin sensitivity in those with diabetes as well.


Why is Coffee Beneficial?


There are a few proposed mechanisms as to why coffee is protective against the development of type 2 diabetes. 


  • A phenolic compound called chlorogenic acid, which is a major component in coffee, has demonstrated the ability to lower blood sugar. It may help lower glucose absorption in the intestines, and reduce the glucose output by the liver.
  • Coffee also contains magnesium, a mineral that has been associated with lower diabetes risk, along with other substances like lignans and quinides, that also help with glucose metabolism.
  • A UCLA study revealed that coffee drinkers have higher levels of sex hormone-binding globulin (SHBG) which can help lower insulin resistance
  • The caffeine in coffee and its effects are mixed. Studies show that caffeine can lower insulin sensitivity in the short term, namely in those who already have diabetes, whereas there has been some animal research suggesting that caffeine may exert beneficial effects on insulin activity in the long term, namely when it comes to preventing development of diabetes in those yet to be diagnosed.


Coffee Considerations


When deciding whether to consume coffee and the best way to do so, you may want to take into account:


  • Caffeinated vs. decaffeinated: for those without diagnosed diabetes, both caffeinated and decaffeinated has shown to be protective. However, if you need to avoid caffeine for other reasons- such as heart/digestive/headache or anxiety issues, you can still get the protective benefits by drinking decaf. For those diagnosed with type 2 diabetes, try paying attention to if the caffeine interferes with your blood sugar control and consult with your health care team about the best choice for you. Everyone responds differently – whereas coffee increases blood sugar in some individuals, others can see a lowering effect .
  • Time of Day: if you have been with diagnosed diabetes, you may find that you are prone to higher blood sugars in the morning and you may want to consider if caffeine compounds the problem. Some find that drinking caffeinated coffee later in the day interferes with sleep and that in turn can affect blood sugar control, so switching to decaf may help.
  • What you put in your coffee: for some it may not be the coffee as much as what you put in it that can be the concern with diabetes prevention and control. Adding too much sugar, heavy cream or choosing coffee drinks with syrups/additives can defeat the purpose of its health benefits and add excess carbohydrates and calories that can interfere with blood sugar and weight control.