Learn everything that you need to know about caffeine, from what it is to where to find it, and how much is considered safe for daily consumption for adults.
Coffee is one of the most popular beverages in the world. You can drink it hot or cold, bitter and black or sweetened with sugar, syrups, or honey and mixed with milk for a creamier taste. It is hugely versatile, and it contains a certain key ingredient that people love: caffeine.
Caffeine is frequently discussed in relation to the negative impact it can have on a person’s sleep habits, anxiety, or health in general, but there are also various benefits caffeine can have when consumed in moderation. This article will take a look at both sides of the story.
We have put together this guide to understanding coffee: the pros and the cons, so that you can have a better understanding of what you are putting into your body and what it will do.
- What Is Caffeine?
- How Does Caffeine Work?
- Drinks That Contain Caffeine
- The Pros of Caffeine
- The Cons of Caffeine
- How Much Caffeine Is Too Much Caffeine?
What Is Caffeine?
Caffeine is typically found in a variety of different drinks and even food, but what exactly is this substance and what effect does it have on adults? That is what this section will look at.
Caffeine Is a Natural Stimulant
First things first: caffeine is a natural stimulant, hence why so many people reach for a mug of joe first thing in the morning when they wake up. Caffeine can be used to help you get going for the day as it provides an energy boost and so helps you feel more awake and alert.
In fact, this stimulating effect is one of the key reasons why caffeine is one of the most commonly used ingredients in the whole world. However, there are both advantages and drawbacks to relying on coffee for its stimulating effect which this article is about to go into.
The highest naturally occurring levels of caffeine are commonly found in drinks such as tea, coffee, and energy drinks, as well as cacao plants. Several experts have traced the first use of brewed, caffeinated tea back to 2737 B.C. according to a number of reliable sources.
From its first use as a naturally-occurring stimulant, caffeine is now added to soft drinks (although it is worth noting that drinking too many sugary drinks is bad for your health) to provide consumers with a boost of energy after drinking them. This started in the 1800s.
Works by Stimulating the Brain and Central Nervous System
Caffeine does more than just create a placebo effect of feeling more alert – it actually affects the body’s central nervous system as it is able to stimulate the brain to create that feeling.
According to a number of experts, including James D. Lane, PhD, Professor of medical psychology at Duke University Medical Center in Durham, N.C. and someone who has dedicated years to the study of caffeine, “caffeine locks the receptor normally used by adenosine, a brain modulator that provides feedback to avoid overstimulation of nerve cells.”
How Does Caffeine Work?
What happens after caffeinated food or beverage passes your lips and enters the body?
Caffeine Is Absorbed From the Gut Into the Bloodstream, Once Consumed
Straight away, caffeine finds its way into your bloodstream from the gut after you have consumed it. This travels to the liver and in order for it to have the desired effect on, it is then broken down into manageable-size compounds to influence the function of certain organs.
From the moment of consumption, it will typically only take around 20 minutes for you to begin feeling the effects of caffeine, so it is clearly a substance that can get to work quickly.
Caffeine’s Main Effect Is On the Brain
As we have already mentioned, caffeine mainly affects the brain and how it sends signals to your body. It does this by preventing adenosine from being able to transmit signals of tiredness or fatigue to the body which results in you feeling less tired and more awake.
Additionally, it can help to increase the adrenaline levels in your blood which also increases brain activity, in particular, the two key neurotransmitters, dopamine and norepinephrine.
At the same time, caffeine is able to decrease the cerebral blood flow to induce a relative brain hypoperfusion, according to an article on caffeine and the central nervous system.
Drinks That Contain Caffeine
Now you know what caffeine is and does, let’s take a look at some of the drinks it is found in. Don’t forget that caffeine can also be found in certain foods as well as in hot or cold drinks!
According to the United States Department of Agriculture (USDA), there are around 90 to 100 milligrams of caffeine in one 1.5-ounce shot of espresso. You might be surprised to learn that this is not, in fact, the most caffeinated beverage you can currently find on the market.
If you opt for a double espresso or if it is a slightly larger measurement, you can expect to consume anything from around 240 to 720 milligrams of caffeine in a cup of espresso.
Compared to an espresso, a standard cup of drip coffee would contain around 128 milligrams of caffeine, so if it all came down to a choice between the two, a regular cup of coffee would provide you with more of a caffeine boost than you would find in an espresso.
With that being said, there are many different types of coffee and different ways of making it, so regular long coffee will often contain anything from 102 to 200 milligrams of caffeine.
So, we hate to be the ones to tell you this, but decaf caffeine isn’t actually caffeine-free.
Yep, you heard us right – even decaffeinated coffee can still contain a small amount of caffeine. The total can be anywhere between three and 12 milligrams, so it is still worth checking how much caffeine your favorite decaf coffee contains so you can stay on track.
This may sound like it is only a trace amount of caffeine, and to the people who frequently drink caffeine as part of their regular diet, it probably is, but this is still enough to affect anyone who is particularly sensitive to caffeine. That means you should keep an eye on it.
Even Soft Drinks, Brewed Tea, and Chocolate Milk Contain Caffeine
You would probably be surprised at some of the drinks that you will typically find caffeine in, even when it is not something that is necessarily marketed as being a caffeinated drink.
Chocolate milk, for example, can contain between two and seven milligrams of caffeine which is the same as pretty much any cocoa beverage that is currently on the market.
The Pros of Caffeine
Looking for a reason to justify or further enable your current caffeine intake? Well, you will certainly find one somewhere in this next section as we discuss a few of the pros of caffeine.
Caffeine Improves Memory
We knew there was a reason why we drank so much of the stuff when we were studying at university… caffeine has actually been proven to improve memory to a certain extent.
This is great news for anyone with a bunch of upcoming exams on the horizon, I’m sure!
Research from Johns Hopkins University revealed that even a small amount of caffeine can help to improve memory. In fact, there have been studies that have shown that even just 200 milligrams of caffeine, taken in the form of a pill, can help boost memory consolidation.
There have also been other studies that have pointed toward an improvement in alertness and performance in mental tasks after consuming a number of small doses of caffeine. In this particular study, the amount of caffeine given to participants was 4 x 65 mg over 5 hours.
So, you better start brewing up some coffee or grab an energy drink if you need to study.
One of the most obvious benefits of caffeine is that it can help reduce feelings of fatigue and tiredness. One study in particular was able to determine that caffeine “relieves pain associated with sleep loss better than analgesics”, resulting in less fatigue overall.
As we have already explained, caffeine stimulates the central nervous system. What you might not already know is that caffeine can actually be absorbed by the body and into your bloodstream in a matter of just 45 minutes after being consumed, which is pretty fast action.
That means that you can grab a caffeinated beverage and expect to feel more awake and alert just over half an hour later. It is the perfect midday pick me up for those who need it.
The one downside to using caffeine as a way to reduce feelings of tiredness is that, as it is explained on bodybuilding.com, “if you continually consume caffeine, your body will adapt to the presence of caffeine by increasing the number of adenosine receptors within the central nervous system.” This essentially means that the total number of adenosine receptors will increase, whilst the desired stimulatory effects of caffeine will begin to decrease over time.
So, the more caffeinated products you consume, the more you will need in order to achieve the same desired effect. However, it is important that you try to avoid consuming too much caffeine, for reasons which we will go into in more detail a little bit later on in this article.
Improves Short-Term Memory and Speeds Up Your Reaction Time
In addition to improving your overall memory skills, caffeine has also been linked to a notable improvement in short-term memory, in particular. WebMD gives the example of a study in which it was found that “caffeine boosted activity in the brain regions related to attention and short-term memory” when using a subject pool of a dozen healthy adults.
But can it really speed up your reaction time? According to Live Science, yes it can, as research has also indicated that caffeine can speed up older adults’ reaction times.
We are not trying to claim that you will suddenly never forget a set of instructions given to you not five minutes before again, or that you would be able to dodge a bullet due to your newfound super fast reaction times, but even just a slight improvement would be beneficial.
Caffeine Before Exercise Increases Fat Burn
Now, there is a reason for the fact that a lot of fat-loss promoting products will typically contain caffeine if you were to check the list of ingredients. This is because caffeine is able to stimulate the central nervous system, which may in turn help to increase your metabolism.
There is still more research that needs to be done before anything can be concretely confirmed from a medical and scientific point of view, but some initial studies have suggested that caffeine may be able to increase metabolism by up to as much as 11 percent as well as being able to aid with fat burning by as much as up to 13 percent.
Okay, so it is hardly a huge amount, but even so, this is not far off the calorie excess that is responsible for the average American person’s yearly weight gain, which is 2.2 pounds.
In all honesty, whilst caffeine has been proven to promote fat loss and to boost metabolism, it is not likely that these will have significant results for you in the long run. Unfortunately, the best thing for fat burn is still a healthy diet and plenty of exercise to keep your body moving!
There is also the fact that caffeine may be able to enhance exercise performance in general, which will obviously lead to a faster rate of fat-loss as you push your body to its limits. On the other hand, it could also be largely due to the fact that caffeine is thought to increase the use of fat as fuel which will help to promote fat-loss throughout the duration of your workout.
Detoxes the Liver and Cleanses the Colon
When taken as a caffeine enema, caffeine has also been known to help detoxify the liver and can also cleanse the colon, according to certain areas of research. This is a form of colon cleansing that is commonly used in alternative medicine, rather than traditional uses.
The procedure involves brewing up a mixture of both caffeinated coffee and water and then inserting it into the colon. Look away from this next part now if you are squeamish, but this happens by means of insertion via the rectum. Ouch – doesn’t sound like something we’d try.
With that being said, this is actually a longstanding practice that has been around since before the 1900s, and coffee enemas are “thought to stimulate bile flow and the production of glutathione, a detoxifying antioxidant”, according to an article by the Healthline.
Relieves Post-Muscle Workout Pain by 48 Percent
Whilst we are not about to coerce you into thinking that you should swing past your nearest local Starbucks before you set about completing a workout in the gym, there has also been some research that has suggested that caffeine can help to reduce feelings of soreness after a workout. This is good news for those who avoid exercise out of fear of DOMS the next day!
(That’s delayed onset muscle soreness, for anyone who is not already a gym bunny).
One study in particular published its findings on the effects of caffeine when it comes to post-workout muscle pain, which were that having moderate doses of caffeine (which would be the equivalent of drinking two cups of coffee) before a workout has the potential ability to reduce feelings of muscle pains and soreness after working out by up to 48 percent! Score!
This was only done on a small selection of subjects, but it is an interesting benefit of caffeine that not many people would think of when it comes to listing its favorable qualities.
The Cons of Caffeine
Although the pros of caffeine probably all sound great to you, as with anything in life, there are also a few drawbacks to consuming too much caffeine, which this next section will cover.
Caffeine May Raise Blood Pressure
Unfortunately, if you consistently consume high quantities of caffeinated food or beverages, you will likely be more at risk of developing high blood pressure and other associated issues.
This is a serious problem for anyone who is already suffering from hypertension, as well as people who do not regularly consume large amounts of caffeine. One study, in which participants who suffered from hypertension were given 250 milligrams of caffeine (this is roughly the equivalent of drinking four cups of coffee), showed that they experienced raised blood pressure for approximately two to three hours after the coffee was initially consumed.
Similar studies have since been conducted and have received similar results, so this is something to consider if you are already someone who is experiencing high blood pressure.
Increased Heart Attacks in Young Adults
Another serious con for caffeine is that it has been linked to an increased number of heart attacks occurring among young adults. Again, this is considered to be a higher risk if you are someone who already suffers from hypertension or if you do not usually consume caffeine.
Experts including Dr. Lucio Mos have determined that young adults that had previously been diagnosed with a mild to moderate case of hypertension were at a higher risk of having a heart attack after drinking four cups of coffee or the equivalent by up to four times as much.
Even moderate consumption of caffeinated beverages and foods can be a cause for concern if you are particularly sensitive to the substance, as this can put you at up to three times the risk of experiencing a heart attack at a younger age. So, this is something to keep in mind.
Linked to Gout Flare Ups
One of the disadvantages of consuming caffeine regularly is that it can be linked to gout flare ups and attacks, which can be incredibly unpleasant for those who suffer from this condition.
There are certain studies that have suggested that suddenly doubling your caffeine intake out of nowhere, for example, could actually increase the risk of you experiencing symptoms of gout pain by up to as much as 80 percent. The sugar that often comes with it doesn’t help!
With that being said, it is admittedly those who binge on caffeinated products and consume it in excessive amounts who are mainly at a risk of experiencing a gout flare up as a result. You might not need to cut out caffeine completely, but you should still moderate your intake.
Could Cause Incontinence
One of the disadvantages of caffeine which is perceived to be more embarrassing (but it shouldn’t be – it is a condition that you cannot help or control, therefore there is absolutely nothing to be embarrassed about), is that excessive consumption can lead to incontinence.
This is particularly true for women, who are especially at risk of developing incontinence issues if they consume more than the recommended daily amount of caffeine each day.
In fact, one study from the University of Alabama found that women who regularly consume high quantities of caffeine are up to 70 percent more likely to experience incontinence issues compared to men. Plus, it often has a worse effect on people with a weak bladder already.
If you are experiencing urinary incontinence then like we have said, there is no need to feel embarrassed or ashamed by it. This is something that affects more than 13 million Americans, the majority of whom are women. However, it is only extremely high levels of caffeine that has been linked to urinary incontinence, so a cup or two a day won’t hurt!
Can Cause Headaches and Indigestion
One of the other less pleasant effects of caffeine consumption is the fact that it can cause headaches and indigestion, which can be highly uncomfortable for you to experience.
Surprisingly, this is often when you suddenly stop consuming caffeine or if you do not have time to grab your first cup of coffee of the day, for example. These are effectively like withdrawal symptoms that your body will go through when it is craving its next caffeine hit.
These symptoms can typically range from mild to severe, depending on how much caffeine you are usually used to consuming, and it can also cause feelings of fatigue and irritability. Unfortunately, this can cause a lot of people who are trying to quit to reach for another cup.
When it comes to indigestion, the bitterness and acidity of coffee can actually increase the acidity of gastric secretions which can cause painful symptoms of indigestion not long after.
The severity, however, will depend on how prone you are to indigestion and acid reflux.
Could Worsen Menopause Symptoms
Recently, studies have been published that point towards caffeine having a negative impact on menopause symptoms. In fact, The Journal of The North American Menopause Society has proven that people who were going through menopause and who also consumed caffeine on a regular basis displayed a wider degree of vasomotor (menopause) symptoms.
Although these findings are still relatively preliminary and more research will need to be conducted before anything can be concluded, many experts would now suggest to people who are going through menopause that it is a good idea to try and limit your caffeine intake.
Reducing your caffeine has also been found to help minimize the risk of developing further issues with your mood, memory, and concentration in premenopausal people. Symptoms of menopause are unpleasant at the best of times, but they will only be exacerbated by the consumption of excessive amounts of caffeine, so it is advisable that you try and avoid this.
How Much Caffeine Is Too Much Caffeine?
Now that we have told you all about the benefits of caffeine and the consequences that can come of drinking too much of the stuff, it is time for us to get into the all important question:
How much caffeine is too much caffeine? Keep reading to find out in this next section!
Up To 400 mg of Caffeine Per Day Is Safe For Adults
In case you didn’t already know, 400 mg of caffeine is around the equivalent of four cups of brewed coffee. This is the amount of caffeine that a number of expert scientists have determined is the limit of what is considered safe for adults to consume on a daily basis.
Controversially, some experts have actually claimed that drinking more than 150 mg of caffeine is too much. So, whilst drinking up to 400 mg of caffeine every day might technically be considered safe, it might be better for you to stick to drinking around 150 mg each day.
The fact that some people are more sensitive to caffeine and its effects than others also plays a factor in how much caffeine is safe for you to consume on a daily basis. If you are more sensitive to caffeine, for instance, you may feel the effects after just one cup of coffee.
Consuming more than the recommended 400 mg amount of caffeine in a day can cause some serious health issues, and in the worst case scenario, it can even result in fatality.
It Is Important To Not Consume Too Much Caffeine, Especially When Pregnant
Another thing we should mention is that it is best to limit your caffeine consumption during pregnancy because high caffeine levels have been linked to some pregnancy complications.
According to the U.S. Food and Drug Administration, people who are pregnant or who are actively trying to get pregnant should try to avoid consuming more than 200 mg per day.
If you are thinking about trying to cut back on your caffeine consumption, then you might experience the following side effects. Think of them like withdrawal symptoms for caffeine:
- Fast heartbeat
- Frequent urination or a loss of ability to control urination
- Muscle tremors
Whether you are cutting back on the caffeine because you are trying to have a baby or for other health reasons, the most important thing to do is to monitor your intake to ensure you are sticking to a reduced amount. And remember, caffeine isn’t only found in coffee!
Caffeine can be controversial in that there are both pros and cons for it, making it hard to determine overall which side outweighs the other. It all comes down to you as an individual and your body’s response to caffeine, and this can obviously vary from person to person.
If you are someone who is particularly sensitive to caffeine or if you are not a frequent coffee drinker but you are hoping to incorporate more coffee into your daily diet, be mindful of the fact that your sensitivity to caffeine will in part depend on how much you usually consume. It is much better to increase your caffeine intake slowly rather than all at once.
Similarly, if you currently consume too much caffeine and you are hoping to cut down, try to ease back slowly rather than cutting it out of your diet completely one day, as this will mean you are more likely to experience a few of the negative side effects of caffeine withdrawals.