How Coffee Can Lower Your Risk of Type 2 Diabetes

By , Category : Diabetes Tips ,Food and Nutrition

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Shapiro_181115Studies show that coffee can affect your chances of developing type 2 diabetes—and it’s even more interesting to see what drinking coffee might mean to someone who is already diabetic. The results are interesting, informative, and even slightly paradoxical!

Coffee, being the world’s most popular stimulant, has naturally attracted a good deal of scrutiny over its possible health risks and benefits. Countless studies have examined the drink’s effects on the heart and brain, how it impacts various diseases and conditions, even whether it helps you to lose weight. Let’s take a further look at the link between coffee and type 2 diabetes.

Type 2 Diabetes—The Quick Version

In cases of type 2 diabetes, the body produces insulin normally but your cells are not able to use it properly. This is a condition called “insulin resistance” and can progress to a point where the body can’t get rid of sugar fast enough and it builds up in the blood. Insulin resistance can come from a multitude of different factors including obesity, genetics, metabolic disorders, or liver issues. There is an associated condition called “prediabetes” which basically means that your blood sugar levels aren’t normal, but not yet high enough to count as diabetes.

How Coffee Lowers Your Risk of Developing Type 2 Diabetes

Unlike with, say, heart disease, coffee is definitely known to reduce an individual’s risk of  developing type 2 diabetes. Depending on the study consulted, increasing your coffee intake by around one cup a day (total consumption becoming around three to four per day) results in anywhere from a six percent to 11% decrease in the risk of developing type 2 diabetes. The exact level of this reduction varies depending on the study involved, the length of time the increase is maintained, whether you’re dealing with decaf or regular coffee (regular showed more improvements), and sample size.

The exact reason this reduction happens isn’t fully understood, but the fact that decaf coffee can provide the same long term effects (and that tea does not) means that the cause isn’t in the caffeine itself. There are a few theories, although none have been definitively proven.

  • Adiponectin: Adiponectin is a protein that is known to help regulate blood sugar levels. Diabetics are known to have lower levels of adiponectin in their bodies while regular coffee drinkers have higher levels.
  • Antioxidants: Coffee contains a large number of antioxidants and some believe this may affect the body’s insulin levels or the insulin substance itself. Among these antioxidants are substances called polyphenols, which have anti-inflammatory properties believed to help protect against conditions like type 2 diabetes.
  • Liver effects: Some of the studies that looked at coffee and type 2 diabetes also noted that coffee appears to have some protective effects on the liver. Non-alcoholic fatty liver disease is strongly linked to insulin resistance, so coffee may reduce diabetes risk as a secondary result of reducing liver disease.
  • Magnesium: Coffee contains magnesium, which has been linked to lower rates of type 2 diabetes. A habitual coffee drinker, especially one who increases their intake, would naturally receive a larger amount of the mineral.

Drinking Coffee As a Diabetic

So, with this information in mind, should someone who is already diabetic drink coffee? Probably not, as it turns out. This is where the above-mentioned paradox comes in. Although the long term effects of coffee show its ability to reduce the risk of developing type 2 diabetes, the short term effects of consumption are quite different.

Coffee can result in increased blood sugar levels and insulin resistance. For someone with diabetes or prediabetes this can be extremely problematic and needs to be accounted for so as to avoid a hyperglycemic incident.

It is worth noting that the heightened blood sugar response is only observed when drinking regular coffee, as it is directly related to caffeine. Decaf provides many of the protective effects without extra impact on your blood sugar. Alternatively, it is known that habitual coffee drinkers can become desensitized to many of caffeine’s effects and this can lead to them not experiencing the blood sugar spike normally expected.

Just to add even more confusion to the mix, some studies have found that prolonged periods of high levels of caffeinated coffee (five cups a day) can result in lower blood sugar levels than decaf or no coffee at all.

The Connection Between Coffee and Type 2 Diabetes: What It Means for You

Regular and decaf coffee are known to reduce your risk of developing type 2 diabetes, although the exact reason for this is still unidentified. If you have prediabetes or are already diabetic, you will want to be wary of how coffee—especially caffeinated coffee—can cause a spike in blood sugar and promote insulin resistance. If you are diabetic and manage to make it within a few months of drinking five cups of caffeinated coffee per day, you may find yourself with lower blood sugar levels than when you started.

Basically, coffee can reduce your risk of type 2 diabetes but if you are already diabetic then you’d better stick to decaf. Of course, all of this assumes you are just drinking your coffee black. If you add milk, cream, sugar, syrups, or other additions available at your local coffee shop, your results will definitely change.

Sources for Today’s Article:
Bhupathiraju, S. N., et al., “Changes in Coffee Intake and Subsequent Risk of Type 2 Diabetes: Three Large Cohorts of US Men and Women,” Diabetologia , 2014; 1346-354, doi:10.1007/s00125-014-3235-7.

Bjarnadottir, A., “How Does Coffee Affect Blood Sugar and Diabetes?” Authority Nutrition, November 13, 2015;
Case-Lo, C., “Coffee’s Effect on Diabetes,” Healthline web site, September 8, 2014;
“Coffee and Diabetes,”,, last accessed November 17, 2015.  
Bhaktha G., et al., “Relationship of Caffeine with Adiponectin and Blood Sugar Levels in Subjects with and without Diabetes,” Journal of Clinical Diagnostic Research , 2015; doi:10.7860/JCDR/2015/10587.5371.
Huxley, R., et al., “Coffee, Decaffeinated Coffee, And Tea Consumption In Relation To Incident Type 2 Diabetes Mellitus: A Systematic Review With Meta-analysis,” Archives of Internal Medicine, 2009; 2053-063; doi:10.1001/archinternmed.2009.439.
“Type 2 Diabetes: Causes, Symptoms, Prevention, and More,” WebMD web site, June 22, 2015;

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Dr. Jeffrey Shapiro, MD

About the Author, Browse Jeffrey's Articles

After receiving athletic and academic awards at Yale and Stanford, Jeff has coached those seeking peak wellness, appeared on ABC News 20/20 and served as a consultant for CBS News 60 Minutes and The Late Show with David Letterman. As the author of many research studies and practicing anesthesiology/critical care medicine for more than 20 years, Jeff can be your guide to common sense decision making regarding drugs, supplements and vitamins. With no corporate sponsors and no vitamins or supplements... Read Full Bio »