Is Coffee Good for Diabetes?

Should people with diabetes drink coffee? If you do, should it be decaf or regular? The health effects of coffee have been well studied, but we still have no definite answer.

I have to admit — I don’t drink coffee and never have. The closest I get is coffee ice cream. But some of this data has me thinking I should start.


• Coffee reduces risk of death. In a study of over 700,000 people done by the University of Southern California, people who drank coffee were 18% less likely to die in the next 10–16 years. The study group included people of various races and ethnic groups.

• Coffee is linked with lower risk of stroke. Since stroke is a major complication of diabetes, lowering your risk seems like a good idea.

• Studies indicate that coffee lowers risk ofliver and mouth cancer, improves memory, and protects against Type 2 diabetes and Parkinson’s disease.

• A recent study from India found that coffee drinkers have lower fasting blood sugars. Other studies have found that coffee improves insulin function. It may lower insulin resistance.

• Some nutritionists say coffee is a major source of antioxidants, molecules that slow aging and tissue breakdown.

Downside of coffee
Coffee has some undesirable side effects. The Mayo Clinic states that consuming more than 500–600 milligrams of caffeine a day may lead to “insomnia, nervousness, restlessness, irritability, an upset stomach, a fast heartbeat, and even muscle tremors.” It’s worth noting that 500–600 milligrams a day is a lot (about six cups of coffee or nine ounces of espresso), but some research has linked even moderate amounts of caffeine to bad health effects, according to Medical News Today.

Coffee drinking in pregnancy may increase the risk of low-birth-weight babies. Drinking coffee with a meal containing carbs seems to raise the after-meal glucose spike.

But coffee also gets an undeserved bad rap. Coffee does not raise risk of heart attack or stroke, according to researchers. Coffee appears not to raise people’s blood pressure more than a few points, and it does so only for a short time.

How can coffee do all these different things? It really is a natural miracle. Each tropical bean contains over a thousand different chemicals. Only about 30 have been studied.

The best-known ingredient is caffeine, which Dr. Steven E. Meredith of Johns Hopkins University School of Medicine calls “the most commonly used psychoactive substance in the world.” Some studies have given people caffeine capsules instead of coffee, but they’re not the same. There’s a lot of other good stuff in coffee.

Some people drink decaffeinated (“decaf”) coffee to reduce the stimulating effect of caffeine. This is where it gets confusing. Some studies show decaf having the same benefits for diabetes as regular coffee, but others do not.

Personally, if I do start drinking coffee, it will be regular. The chemical processes involved in making decaf sound like they couldn’t be healthy, although there’s not much scientific evidence for that.

So is coffee good for people with diabetes or not? Dr. Meredith believes individuals vary in their response to caffeine, which “may explain why there are mixed messages surrounding whether [it’s] good or bad for us.”

I notice that coffee is found in some studies to lower fasting glucose levels, but in others to raise post-meal levels. So it might make sense to drink coffee away from mealtimes. I haven’t seen any studies on this idea, though.

You will have to decide if it’s right for you. Hope this information, along with speaking with your health-care provider, helps you decide. You can see a lot more about coffee, specifically for diabetes in “The Mystery of Coffee and Diabetes.”

Want to learn more about coffee and diabetes? Read “Coffee: Friend or Foe? (Part 1)” and “Coffee: Friend or Foe? (Part 2).”