Diabetics, rejoice: For some, an extra cup of coffee might be just what the doctor ordered

By Anastasia Climan, RDN, CD-N | Fact-checked by Barbara Bekiesz
Published September 5, 2023

Key Takeaways

  • Coffee has several bioactive compounds that are protective against diabetes and diabetes-related complications.

  • There’s evidence that drinking two cups of coffee each day is beneficial, and even up to four cups is likely safe for most.

  • Other lifestyle goals should take priority over quitting coffee, but if their morning cup of joe spikes your patient’s blood sugar, they might consider monitoring their consumption.

Epidemiological studies have linked the daily consumption of two to four cups of coffee with a lower risk of type 2 diabetes, according to research published in Food and Chemical Toxicology.[]

But how does coffee affect people who are already diagnosed and living with diabetes? Although coffee is filled with beneficial plant compounds, it can also be high in caffeine, sugar, and cream, depending on how it is prepared. Patients can easily feel confused by mixed messages about their beloved morning brew.

Due to sometimes conflicting research, answering diabetes patients’ questions about coffee may give you the jitters. Here’s how to offer an evidence-based perspective.

Coffee’s anti-inflammatory properties

In the United States, 83% of adults drink coffee. However, not every cup is created equally. In fact, the compounds in coffee can vary quite a bit based on how it’s brewed.

The primary bioactive compounds in coffee include:

  • Chlorogenic acid: This is an antioxidant and the most abundant phenolic compound in coffee.

  • Diterpene alcohols: These are strong coffee antioxidants, which include cafestol and kahweol.

  • Trigonelline: After caffeine, this is the second-highest alkaloid in coffee.

These coffee compounds have established anti-obesity effects, according to the Food and Chemical Toxicology authors, as does caffeine. In addition, studies demonstrate coffee’s ability to lower inflammatory markers like C-reactive protein and leptin, as reported in a 2023 international study in Clinical Nutrition.[]

Coffee intake has also been linked to higher adiponectin levels. Adiponectin is not only anti-inflammatory, but it also boosts insulin sensitivity. Low levels of adiponectin are associated with higher rates of diabetes, obesity, and heart disease.

Less-processed coffee drinks produce the strongest effects, the Clinical Nutrition researchers found, with more significant benefits observed in ground coffee and espresso vs decaf or instant coffee. As a result, the net positive of coffee intake on a progressive and inflammatory disease like diabetes is hard to deny.

Coffee’s impact on diabetes complications

In the United States, diabetic retinopathy (DR) impacts 40% of those with diabetes, strongly affecting their quality of life.[] Although researchers have yet to confirm a causal relationship, Korean investigators reported that drinking two cups of coffee per day is significantly associated with a lower rate of DR vs drinking no coffee.[]

After analyzing data from 1,350 participants, the study investigators noted that, “[R]egardless of the type of coffee, the prevalence of DR tended to decrease with increases in coffee intake of both black coffee and coffee with sugar or cream, adjusted for confounders such as energy intake.”

While it’s not as clear whether coffee has the power to ward off other diabetes complications, such as kidney problems or heart disease, its overall anti-inflammatory effects are promising for a multitude of conditions.

Nonetheless, clinicians should keep in mind that caffeine may affect people differently. Up to 400 mg of caffeine is considered safe for most adults (the amount in three to four cups of coffee).[]

But for some people with diabetes, caffeine leads to unexpected blood sugar fluctuations that interfere with glycemic control and the action of diabetes medications. In addition, sweetened coffee drinks can be a significant source of carbohydrates and should be accounted for as part of the total diabetes diet.[]

For people with diabetes, as for many others, drinking coffee is often more than just a dietary choice. It’s a morning ritual that can be tough to change. Fortunately, coffee is generally something you don’t need to encourage your patients with diabetes to give up. Instead, prioritizing healthy weight loss, physical activity, and medication compliance are likely more worth your while.

What this means for you

Many people with diabetes will benefit from drinking a couple of cups of coffee per day, regardless of how it’s prepared. Coffee has known antidiabetic effects and may be protective against obesity, diabetes progression, and related complications. Encouraging patients to monitor their blood sugar can help identify individual differences in response to caffeine or sweetened coffee drinks.

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