Is Caffeine Bad For You? What The Science Says

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Is caffeine bad for you? Have you ever wondered that? I mean are you someone who has to have your caffeine fix first thing in the morning to get your day going? Do you love caffeine? If the answer is yes, trust me you're not alone because it is actually, the most commonly used drug worldwide and yes it is a drug, it's a stimulant. And the thing is, we believe that it has some beneficial effects but it also has some potentially dangerous effects as well. Today we're going to answer the question, is caffeine bad for you?


What Is Caffeine?

Well, caffeine is a drug, it's a stimulant. It is the most commonly consumed stimulant worldwide. It's a methylxanthine actually. And in its pure form caffeine is a white crystalline powder with a bitter taste. And you can find it in different places in nature. You can find it in coffee beans, in tea leaves, and you can find it in cocoa beans. You can even find it in the flowers of some citrus plants.


How Does Caffeine Affect The Body And Brain?

Caffeine affects your brain and your body. It affects your central nervous system and other parts of your body as well. So let's start with the central nervous system. It can work by blocking adenosine receptors so what in the world does that mean?

Well, you have these adenosine receptors in your body and when adenosine gets to them, it causes you to relax and maybe even feel a little drowsy, a little sleepy. That's when adenosine gets to them. But what it does, it blocks those adenosine receptors. And so the adenosine can't get to them and it keeps you from being tired. It actually makes you more alert and stay awake. And so that is one way it affects your central nervous system.


how caffeine affects the brain and body


Adenosine receptors are in other places on your body as well. You have adenosine receptors specifically the A1 receptors on your heart and your kidney. So again, when the adenosine is on these receptors in the heart, then it can cause the heart to have a slow heartbeat.  But if it gets to these receptors it will cause a faster heart rate. So caffeine can have the effect of speeding up your heart rate. You may have felt that before.

You also have adenosine receptors on your kidneys. When you have those adenosine receptors that are taken up by adenosine you tend to have a bit of a slower or lower urine output. You're not urinating as much, but again, when caffeine gets to those receptors you tend to urinate more and more frequently, and so you may notice, that when you're drinking a lot of caffeine you're running to the restroom, and you're urinating a lot. Caffeine also can affect your muscles as well.  It causes calcium to be released from muscles.


Benefits Of Caffeine

Now I want you to understand, that there is not enough data in order to promote or discourage caffeine use. However, there are certain benefits that we do believe you can find as well.

  • Caffeine can make you more alert - it can make you more feel alert, more awake, and more focused.
  • Can help with memory - We also believe that in some cases it can help with memory but we're not sure if it's actually helping your memory or if it's just taking away some of the withdrawal symptoms if you have somewhat of an addiction to caffeine.
  • May help decrease symptoms of depression - Another possible benefit is that in low to moderate doses, it may help to decrease depressive symptoms.
  • May be beneficial in some long-term neurodegenerative disorders - And there are some studies that suggest, that caffeine may actually be beneficial long-term in certain neurodegenerative disorders like Parkinson's disease and Dementia.
  • Medicinal purposes - Caffeine can be used in premature infants who have difficulty breathing. If they have spells where they stop breathing for short periods of time, apnea of prematurity, then it can actually help.


caffeine withdrawa


Side-Effects of Caffeine

Remember, there's not enough data in order to promote or discourage the use of caffeine. But we do know is that there are definitely some side effects that can affect your health. So is caffeine bad for you? First remember, that we believe that as long as you are not consuming more than 400 milligrams of caffeine a day as an adult, then it likely will not have a lot of adverse effects. For children and adolescents, it's not studied as well, but we believe, that if children consume less than 2.5 milligrams, per kilogram of body weight, that it is not likely to have bad effects on them either. But kids have to be careful and adults as well. You don't want to mix caffeine with other substances, like teenagers having energy drinks and mixing them with alcohol or other pills, sleeping pills, drugs, or substances.

Now, okay, here are some of the side effects:

  • Restlessness
  • Anxiety
  • Can worsen high blood pressure - If you're a person with high blood pressure, caffeine in some cases can exacerbate it or make your blood pressure worse.
  • Jitteriness
  • Fast heart rate - if you're a person who already has a fast heart rate or tachycardia, especially if you have an abnormal heart rate or you have an arrhythmia, then potentially, this fascinating or quickening of the heart rate from the caffeine could be a potentially negative side effect for you.
  • Dehydration - I mentioned that caffeine can cause a blocking of the adenosine receptors in the kidney and it can make you urinate more frequently. Well, this can actually cause dehydration and we know that dehydration can lead to other problems like kidney failure.

Caffeine Addiction -

You can also develop a tolerance to caffeine, where you need more and more. And so I mentioned that we believe that 400 milligrams or less, has a pretty low potential for causing bad problems. But if you're someone who drinks coffee daily and if you're drinking 400 milligrams to get that alertness, that focus, or memory sharpness that you want,  your body actually may develop a tolerance.

So in other words, it blocks those adenosine receptors and keeps you awake. Your body might actually make more adenosine receptors. What does that mean? That in order for caffeine to block those adenosine receptors, it's going to require that you drink more and more.

Caffeine Withdrawal -

And then there's withdrawal, if you become addicted and yes, as mentioned, you can become addicted to caffeine, then it can lead to withdrawal. If you are a regular consumer of it and you're having it daily, then if you stop suddenly you may feel caffeine withdrawal symptoms such as:

  • Headache
  • Fatigue
  • Irritability
  • Flu-like symptoms
  • Struggle to concentrate

These withdrawal symptoms can last anywhere from a few hours to a few days. And a lot of folks will just have more caffeine in order to get over the withdrawal. But it's really an important concept because, you really just don't want to be addicted to anything, to rely on a stimulant in order to function. And so it's important that you're aware that caffeine can definitely be addictive.

what is caffeine

How Much Caffeine Should You Have In A Day?

And remember, we believe that if you're taking in less than 400 milligrams of caffeine a day then you're not likely to have a lot of harmful effects. And again, for adolescents and teens, we believe that 2.5 milligrams per kilogram, per day or less, should be okay.

Do know that it is possible to have toxicity from caffeine and overdose? But that would take 10 grams 10,000 milligrams of caffeine! So not likely, but yes there is such thing as caffeine toxicity.


How Much Caffeine In Foods and Drinks?

Let's talk about how much is in the foods and the drinks that we take in each day.

  • AriZona Green Tea - has just over 11 milligrams of caffeine per can.
  • AriZona Mucho Mango Tea - they actually make this tea with no caffeine but there was a time where you could get it and it would have 120 milligrams. So just make sure you're watching your labels.
  • Peace Tea has only 23 milligrams in a 20-ounce can.
  • Chocolate - chocolate does have caffeine. And if you're looking at your typical chocolate bar, or your milk chocolate bar it's going to have about eight milligrams in it.
    - Milk chocolate - an ounce of milk chocolate, has about 3.5 milligrams per ounce of milk chocolate.
    - Dark chocolate  - has a little bit more a higher caffeine concentration. An ounce of dark chocolate has about 13.3 milligrams.
  • Chocolate Covered Espresso Beans - Now, if you have ever been in a situation where you have to be up all night studying, or if you're working a night shift, or you need to stay awake you may have had a Chocolate Covered Espresso Bean. There's a lot of caffeine in these beans,  Just one ounce of Chocolate Covered Espresso Beans has 230 milligrams. And so again, everything in moderation but you really want to be mindful of how much caffeine you're taking in when you're consuming these espresso beans.


is caffeine bad for you?


  • Green Tea  - a tea bag with 230 milliliters of water will have between 30 and 40 milligrams, this one serving of tea.
  • Coffee - Coffee is tricky because it's really going to vary depending on what kind of coffee you have, how it's brewed, where it comes from, and the coffee beans. But coffee can vary anywhere from 65 to about 300 milligrams. And so that's kind of the wild card, you really have to pay attention to how many cups of coffee you're drinking and pay attention to where you're getting it from.
  • Energy drinks - These are the caffeine-filled drinks that many people take in to try to stay alert, and stay focused, but pay close attention because if you're not careful you can really go over that daily limit of caffeine.
    - Red Bull - In 12 ounces of Red Bull, you get 114 milligrams
    - Monster Juice -  In on can you have 160 milligrams
    - C4 Energy - One can have C4 energy has 200 milligrams
    Bang - One can of Bang has 300 milligrams

So these are just some of the examples, reminding you to be careful label watchers because there are foods that you eat, things that you drink that have caffeine and you must be aware of what you're putting in your bodies.


Is Caffeine Bad For You?

Okay, so what's the answer to the question is caffeine bad for you? Well, there is no black and white, or right or wrong answer.  Remember we don't have enough scientific data to either promote or discourage the use of caffeine. What we do know, is that there are certain dangerous side-effects and you must be aware of them. On the same note, there are some potential benefits. It is important that you consult your physician to find out, how much caffeine is going to be safe for you.

The general rule is less than 400 milligrams a day for adults, but again, consult your physician. Caffeine is the most widely consumed stimulant in the world. And so this definitely affects a lot of people. We have over 150 million Americans who consume coffee daily. So the next time you pick up your cup of coffee, a cup of tea, or you're grabbing that energy drink, just really be cognizant.

Think about how much caffeine you're taking in and make sure you do things in moderation. And while you're getting those benefits, like being alert being awake, trying not to be sleepy, trying to focus, or to do things in a more efficient way, think about the potentially dangerous effects as well,  like developing tolerance or getting withdrawal symptoms or having a fast heart rate, or dehydrating yourself. Everything in life is about balance.

Dr. Frita - Frita McRae Fisher, M.D.
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