How Caffeine Affects Blood Sugar Levels

Whether it’s your morning cup of coffee, an afternoon green tea, or a pre-workout energy drink, caffeine is a daily ritual for many. Caffeine can help boost alertness and concentration while even enhancing physical performance. However, if you're trying to manage your blood sugar, especially with diabetes or prediabetes, it's essential to understand how caffeine interacts with your body’s glucose levels.

Unfortunately, the relationship between caffeine and blood sugar isn’t always straightforward. While some studies suggest that regular coffee consumption may lower the risk of developing type 2 diabetes, others show that caffeine can temporarily raise blood sugar levels and reduce insulin sensitivity, particularly in those already living with diabetes. Here, we'll explore the relationship between the two and provide more insight into how caffeine affects blood sugar levels.

What Is Caffeine?

Caffeine is a natural stimulant found in coffee, tea, and chocolate. Other sources of caffeine include energy drinks and some medications. Regardless of the source, caffeine helps stimulate the central nervous system and makes you more awake and alert. This is because it blocks the effects of adenosine, the chemical in the brain responsible for promoting relaxation or sleepiness.

Caffeine is absorbed quickly by the body, usually reaching peak levels in the blood within 30 to 60 minutes after consumption. Its effects can last three to six hours, depending on metabolism, age, and tolerance. According to many experts, up to 400 milligrams of caffeine is safe for most healthy adults, but everyone is different.

The Link Between Caffeine and Blood Sugar Levels

For most adults, caffeine doesn't have a notable effect on blood sugar. However, for people living with type 2 diabetes, caffeine may affect the way your body uses insulin. This can result in higher or lower blood sugar depending on individual circumstances. These effects of caffeine may happen with only 200 milligrams of caffeine, so it's important to check your blood sugar levels and see how your body reacts.

One reason why caffeine can cause fluctuating blood sugar levels is that it can lower insulin sensitivity. This means that coffee may make it harder for your cells to react to the hormone.

A study found that people with type 2 diabetes who took a 250-milligram caffeine pill at breakfast and another at lunchtime found that their blood sugar was 8% higher than on days when they didn't have caffeine. The readings also spiked by more than 8% after each meal.

But why does caffeine noticeably affect blood sugar in some people with type 2 diabetes? The direct link is still being researched, but some experts believe that it's due to the increase in certain stress hormones like adrenaline after drinking coffee or other caffeinated beverages. Adrenaline can also decrease the amount of insulin your body makes. Another reason is that caffeine can reduce your sleep quality, and poor sleep quality and duration can lower insulin sensitivity.

If you have concerns about caffeine and the ability to control your blood sugar, it's best to talk with your doctor.

Long-Term Effects of Caffeine

The long-term effects of caffeine on people with diabetes are complex and, in some cases, contradictory. While short-term studies often show that caffeine can raise blood sugar and reduce insulin sensitivity, long-term consumption, especially coffee, may be associated with beneficial health outcomes. Some of the most conflicting things about short-term vs. long-term caffeine intake include the following.

Chronic caffeine consumption may lead to a sustained reduction in insulin sensitivity, particularly in individuals with type 2 diabetes. However, the body can build tolerance over time, potentially blunting caffeine’s impact on blood glucose after regular use. It may even improve glucose metabolism over time.

Several studies show that long-term coffee consumption is linked to a lower risk of developing type 2 diabetes. However, similar benefits were found regardless of whether the coffee was caffeinated or decaffeinated, which may mean that coffee, not caffeine, is the beneficial factor at play.

Individual Factors That Influence Caffeine’s Impact

Although a certain amount of caffeine daily is generally safe for most people, it's important to understand what works for you. Some individual factors that can impact caffeine's effect on the body include the following:

• Your genetic makeup determines how quickly your body metabolizes caffeine.
• As we age, our metabolism generally slows down, which can make the effects of caffeine more pronounced or longer-lasting.
• People with diabetes, anxiety, high blood pressure, or heart conditions may be more sensitive to caffeine's effects.
• In particular, individuals with type 2 diabetes may experience a temporary rise in blood sugar after consuming caffeine.
• If you're already stressed or sleep-deprived, caffeine may amplify those issues.

You may also be hyper-sensitive to its effects if you don't drink much caffeine. Therefore, it's important to be mindful of any hidden caffeine in foods or drinks you may not realize. For example, dark chocolate, protein bars, soft drinks, and even over-the-counter pain relievers can contain caffeine, so always check labels.

Coffee vs. Other Caffeinated Beverages

It's important to note that where the caffeine comes from can also impact whether or not you experience a spike in blood sugar. For example, brewed coffee or tea may not affect your blood sugar in the same way as a sugar-filled energy drink. Plus, depending on the type of coffee, there can be compounds that are beneficial for blood sugar management. Black tea and green tea have similar benefits.

Energy drinks or sweetened beverages, especially those with high levels of caffeine, are often best avoided. Supplements and pre-workout formulas are also high in stimulants, but they have been less studied.

Tips for Managing Caffeine Intake and Blood Sugar

The average individual drinks about two 8-ounce cups of coffee a day with no negative effects, but this can vary quite a bit from person to person. To help minimize blood sugar fluctuations and reduce the risk of developing long-term complications, it’s important to learn how caffeine affects your body. Here are some practical strategies to guide you:

1. Monitor Blood Sugar Before and After Caffeine

Check your blood glucose levels before and one to two hours after consuming caffeinated beverages. This can help you spot trends or spikes related to your caffeine intake.

2. Keep a Food and Drink Journal

Track what you eat and drink along with your blood sugar readings. Over time, this can reveal patterns, such as whether caffeine contributes to unexpected highs or lows.

3. Consider Decaf or Lower-Caffeine Alternatives

If caffeine affects your glucose levels, try switching to decaffeinated coffee, herbal tea, or drinks with lower caffeine content. These options can offer the ritual of a warm beverage without the added impact on blood sugar. Alternatively, cut the cups of brewed coffee or tea to one in the morning.

4. Avoid High-Sugar Caffeine Combos

Skip sugary coffee shop drinks, sweetened energy drinks, or soda, which can cause a double blood sugar spike due to caffeine and high carbohydrate content. Opt for unsweetened or lightly sweetened options when possible.

5. Talk to Your Healthcare Provider

If you're unsure how caffeine impacts your blood sugar or if you’re experiencing frequent fluctuations, consult your doctor or a diabetes specialist. They can help tailor advice to your unique health needs.

Final Thoughts: Should You Quit Caffeine?

If you find that including caffeine in your diet affects your blood sugar, it's best to talk to your doctor. Limiting the amount of caffeine per day or serving may help, but it's important to put your health and safety first.

Caffeine affects blood sugar levels in complex ways that can vary from person to person. While moderate consumption may not be harmful and could even offer some long-term health benefits, people living with diabetes or who have insulin resistance should pay close attention to how their bodies respond. Monitoring your blood sugar after consuming caffeine can help you make informed decisions about your diet and overall health.

If you're managing diabetes, having access to the right tools and supplies is essential. That’s where Byram Healthcare comes in. We carry a wide range of diabetes management products that can be delivered directly to your door. We also partner with various public and private insurance providers to help you offset costs when possible. To learn more about our diabetes care programs or inquire about product specifications, contact us today.