Does Caffeine Affect Blood Sugar? What People With Diabetes Should Know

Have you ever noticed a difference in your blood sugar after drinking a cup of caffeinated coffee or tea? According to the Mayo Clinic, caffeine can cause fluctuations in your blood sugar levels. Being mindful of how much caffeine you consume can help make blood sugar management easier.

Another study published by the ADA suggests that people with type 1 or type 2 diabetes can reduce their risk of hypoglycemia overnight by having a small to moderate amount of caffeine before bed. Some people also claim that symptoms of hypoglycemia become more noticeable when incorporating caffeine into their diet.

The effects of caffeine can vary from person to person based on your body’s sensitivity to the stimulant. Some people report noticeable effects of caffeine on their blood sugar levels, while others see little or no impact.

Let’s explore some variables that could contribute to the shift in blood glucose levels in relation to caffeine consumption.

Why Caffeine Can Spike Your Blood Sugar

We often think that it’s the caffeine itself that gives us energy when we drink a cup of coffee, tea or soda, but it’s actually related to what the caffeine triggers hormonally in our body.

Caffeine is a stimulant that gives you energy in a variety of ways, explains Science Direct:

• Caffeine blocks “adenosine receptors” from binding to your cells. Normally, these receptors bind to your cells to help you fall asleep. By blocking this binding, caffeine increases cellular activity.
• Caffeine also increases the effects of other natural stimulants produced by your brain: serotonin, dopamine and acetylcholine. These all give you an extra boost!
• Caffeine increases your body’s release of adrenaline. This is why caffeine can raise your blood sugar.

We also tend to think of adrenaline as something that simply gives us energy, but like caffeine, it’s more complicated than that! Instead, adrenaline actually triggers your liver to release stored glucose, giving you the fuel you need to endure a soccer game, a rollercoaster ride or your usual Monday morning.

Why caffeine affects everyone differently

For some people, a cup of coffee in the morning may cause no spike at all, but if you consume two or three cups, you may surpass your body’s tolerance for caffeine and can see a steep rise in blood sugar.

Another variable might be when you drink caffeine. Your body may tolerate it fine in the morning, but a single cup of coffee in the afternoon could send your blood sugar soaring. Take good notes to pinpoint how your body reacts to caffeine depending on when you have it.

It might not be the caffeine spiking your blood sugar

Certain common side effects of caffeine consumption may often explain shifts in blood sugar levels.

• Lack of sleep. Not enough sleep has proven to contribute to insulin resistance in the body for people with type 1 diabetes. Too much caffeine could certainly contribute to insomnia, especially since caffeine tolerance decreases as we grow older.
• Heartburn, upset stomach, or dehydration. Some people are less tolerant of coffee and other caffeinated beverages than others, so heartburn, upset stomach, and dehydration can often occur. Your body’s hormonal responses to these symptoms (and feeling ill in general) may cause blood sugars to rise.
• Dawn phenomenon. The dawn phenomenon is the term used to describe an abnormal rise in blood sugar levels in many people, between the hours of approximately 2 a.m. and 8 a.m. Most researchers believe this effect to be the result of hormone surges—the body’s overnight release of cortisol, glucagon and epinephrine, which all increase insulin resistance.

Don’t forget about sweeteners and add-Ins

Of course, if you plan on sweetening your caffeinated beverage with sugar, cream or milk, always check the carb count and bolus or take your injections accordingly!

While artificial sweeteners don’t cause a rise in blood sugar, they often contain other ingredients that may cause hyperglycemia.

The bottom line on caffeine and blood sugar

So—what is the takeaway from all of this? Everyone’s body reacts differently to foods and beverages, whether or not someone has diabetes.

It is important to keep in mind that studies thus far on caffeine and BG levels remain inconsistent. Knowing exactly how much effect it could have on you will take some experimentation, and could be dependent on many things—including time of day, carb counts, physical activity, hormone levels, and the amount of caffeine ingested.