Is Coffee Bad for Diabetics?

Like most people, I can’t start my day without coffee. I joke that I’d put Starbucks out of business if I gave it up. But I may need to cut back. Research shows that while coffee may lower the risk of developing type 2 diabetes, it may cause issues for type 2 diabetics.

Coffee Lowers the Risk of Type 2 Diabetes

A study in Diabetologia showed that participants who increased their coffee consumption by over one cup per day over a four-year period had an 11% lower risk of type 2 diabetes. Those who lowered their daily coffee consumption by over one cup had a 17% higher risk for diabetes. The research defined a cup of coffee as eight ounces, black, or with a small amount of milk and/or sugar.

“Our findings confirm those of previous studies that showed that higher coffee consumption was associated with lower type 2 diabetes risk,” said Shilpa Bhupathiraju, lead author and research fellow in the Department of Nutrition at HSPH. “Most importantly, they provide new evidence that changes in coffee consumption habit can affect type 2 diabetes risk in a relatively short period of time” (Increasing daily coffee intake may reduce type 2 diabetes risk | News | Harvard T.H. Chan School of Public Health).

Benefits of Coffee

Coffee contains polyphenols, which may help prevent inflammatory illnesses, such as type 2 diabetes. As well as polyphenols, coffee contains the minerals magnesium and chromium, which are linked with lower rates of type 2 diabetes (Coffee and Diabetes – Benefits of Coffee & Effect on Blood Sugar).

Coffee and Type 2 Diabetes

But what if you have diabetes?

A 2020 British study found that drinking two cups of coffee before eating breakfast increased blood sugar levels by 50%.

Professor James Betts, Co-Director at the University of Bath said, “Put simply, our blood sugar control is impaired when the first thing our bodies come into contact with is coffee, especially after a night of disrupted sleep. We might improve this by eating first and then drinking coffee later if we feel we still feel need it. Knowing this can have important health benefits for us all.”

Problems with Coffee at Breakfast

Many diabetics wake up with high blood sugars because of the Dawn Phenomenon or the Somogyi Effect (https://backtonaturediabetic.com/two-reasons-your-blood-sugar-is-high-at-3-am/). Drinking coffee may worsen already high blood sugar levels.

However, it’s not coffee itself that can be bad for diabetics, but the caffeine in coffee.

First, caffeine in coffee can increase blood sugar levels and lower insulin sensitivity. Coffee can also increase insulin resistance in type 2 diabetics. 

Second, caffeine increases hormones such as cortisol and adrenaline in the body, which increase blood sugar levels.

Third, caffeine also blocks a protein named adenosine. This protein regulates how much insulin your body makes and how your cells respond.

Coffee Alternatives

I doubt many of us will do as the British research suggests and wait until after breakfast to drink coffee. Most people like to drink their coffee with breakfast. Luckily, you can still enjoy your morning brew and reduce the risks of increasing blood sugars. For instance, you can switch to decaf. Decaf coffee still contains minerals such as potassium and magnesium. For diabetics, these minerals help to improve insulin sensitivity and improve blood sugar levels.

You can also drink half a cup, or switch to half decaf (half-caff) coffee. My favorite instant decaf coffee is Taster’s Choice because it’s so smooth. I also like Folgers and Starbucks Via Italian Roast, which are bold in flavor. For half-caff k cups, I drink Green Mountain and Folgers, which are mellow and smooth.

Another alternative is green tea. Green tea has many benefits because it’s loaded with antioxidants. I didn’t care for the herbal, bitter taste of green tea, but I have found one I like, Teavana Emperor Clouds and Mist. It has a light and smoky taste. There are also green teas mixed with fruit and other flavors.

Unlike caffeinated coffee, green tea is beneficial to diabetics. Studies show that drinking green tea is associated with decreased fasting glucose and A1C levels (https://pubmed.ncbi.nlm.nih.gov/23803878/). And green tea has less caffeine than coffee, two to three times less.

Don’t Make Coffee Unhealthy

You can negate coffee’s benefits by adding too much milk and sugar. Also, some specialty coffee drinks have as many carbs as a meal. To make coffee healthier, you can use stevia or monk fruit to sweeten coffee, which won’t affect blood sugars. These sweeteners also do not have the negative effects associated with other sugar substitutes (https://backtonaturediabetic.com/the-best-sugar-substitutes-for-diabetics/). And just a splash of milk or alternative milk can make black coffee less bitter.

Conclusion

Coffee can help reduce the risk of type 2 diabetes. By contrast, research shows that caffeine in coffee can raise blood sugar levels and increase insulin levels in diabetics. Like most people, I would find it impossible to give up coffee. But what we can do is drink less regular coffee and drink more half-caffeinated coffee. We can also switch to decaf coffee, which also contains the minerals found in regular coffee. Minerals like magnesium and potassium are beneficial to diabetics, which might convince you to switch. We can also drink more green tea, which has a fraction of the caffeine and may improve A1C levels.

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