Foods and drinks directly affect blood glucose levels. This means that dietary choices are especially important for people with diabetes.
This has led some people with diabetes to wonder whether coffee or possibly caffeine may be beneficial.
Coffee contains many chemicals beyond caffeine, and according to current research, it seems that some have beneficial effects, while others have less positive ones.
This article looks at scientific investigations into the effects of coffee on diabetes and diabetes risk.
Polyphenols are molecules with antioxidant properties believed to help prevent a wide range of diseases, including type 2 diabetes, heart disease, and cancers.
Antioxidants help keep the heart healthy. People with diabetes have a higher risk of developing heart disease and stroke, and eating plenty of foods that contain antioxidants may help reduce this risk. Read about antioxidant-rich foods here.
Coffee also contains the minerals magnesium and chromium. Increasing magnesium intake has been linked to lower rates of type 2 diabetes.
However, coffee contains very small amounts of these nutrients, compared with other foods; it is far from the most reliable source of these minerals.
The following sections look specifically at how components of coffee may affect diabetes.
According to research, drinking 3 to 4 cups of coffee per day could help reduce a person’s risk of developing type 2 diabetes.
In a large 2013 study, people who increased the amount of coffee that they drank by more than 1 cup per day over a 4-year period had an 11% lower risk of developing type 2 diabetes than those who made no changes to their coffee intake.
The study also found that people who decreased their coffee consumption by more than 1 cup per day had a 17% higher chance of developing type 2 diabetes.
In a press release, the lead author of the study, Shilpa Bhupathiraju, Ph.D., stated:
“Our findings confirm those of previous studies that showed that higher coffee consumption was associated with lower type 2 diabetes risk. […] 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.”
In a review published a year later, scientists analyzed 28 studies, including more than 1 million total participants. The researchers found that both caffeinated and decaffeinated coffee reduced the risk of developing type 2 diabetes.
The accumulated evidence strongly suggests that drinking coffee may help protect against this condition.
Plain coffee does not seem to directly increase levels of blood sugar, or blood glucose. This is good news for people with diabetes who like black coffee.
However, some research suggests that the caffeine in coffee could impair insulin sensitivity, which is not ideal for people with diabetes.
That said, other compounds in coffee — notably magnesium, chromium, and polyphenols — may play a role in improving insulin sensitivity, which may offset the effects of caffeine.
Because of this, some experts suggest that people with diabetes drink decaffeinated coffee — to get the benefits of components such as antioxidants and minerals without affecting insulin sensitivity.
According to a small pilot study in people with type 2 diabetes, drinking caffeine before exercising may reduce blood sugar levels.
Another study in people with type 1 diabetes suggests that taking a caffeine supplement could modestly attenuate low blood sugar during exercise. However, the researchers caution that this could increase this risk of late-onset low blood sugar.
Caffeine is the major stimulant in coffee. It occurs naturally in coffee beans and green tea. Caffeine speeds up the central nervous system and may increase mental alertness, relieve tiredness, and improve concentration.
In the general population, the Food and Drug Administration (FDA) report, 400 milligrams of caffeine — or 4 to 5 cups of coffee — per day usually have no negative effects.
However, because research in people with diabetes has been mixed, it is a good idea to ask a healthcare provider about how much coffee is safe.
Some people are more sensitive to the effects of caffeine than others. This is true for people with or without diabetes.
Some experts suggest that decaffeinated coffee is the safest option for people with diabetes because it provides the benefits of other coffee components without the potential risks of caffeine.
It is also important to note that adding sugar or creamer to coffee increases blood sugar levels.
People with diabetes benefit from choosing drinks without added sugar.
Some people use artificial sweeteners, but research indicates that some of these products, particularly sucralose, may affect blood sugar levels in a way that is harmful.
A diabetes-friendly noncaloric sweetener such as monk fruit may be a more healthful choice when a drink needs sweetening. A person might try using a bit less each day, aiming to eventually cut out sweeteners altogether.
Coffee contains many chemicals that have different effects on the body. Some are beneficial for people with diabetes, while others may be less healthful.
Research suggests that coffee may reduce a person’s risk of developing type 2 diabetes.
For people who live with diabetes, the guidance from scientists is mixed. Some studies say that caffeine may reduce insulin sensitivity, though other healthful chemicals in coffee could attenuate these effects.
For this reason, some doctors believe that switching to decaffeinated coffee is a safer bet.
It is crucial to note that coffee with sugar or creamer can raise blood sugar levels. For a person with diabetes, the most healthful way to drink coffee is black or with a natural alternative sweetener.