Is caffeine bad for you?

For many people in the modern world, the morning cup of coffee or afternoon energy drink seems like a part of the very fabric of society.

We hear so much about caffeine. So we thought we would find out what the deal is once and for all. Is caffeine good for you? Is it bad for you? Is it both?

Within this article we’ll do our best to dispel any myths and decanter the truth. 

What is caffeine?

As a household item, caffeine is something that we use to wake up in the mornings or to give us a bit of an energy boost. But outside of that, how much do we really know?

In its natural habitat, caffeine is a toxin that some plants produce to work an all-around defence mechanism.

it’s a natural insecticide which does a good job of paralysing and killing off nasty pests which could threaten the plant.¹

It works by saturating soil around the coffee seedlings with caffeine, which inhibits other nearby seedlings from germinating.²

This basically guarantees that the most caffeine-rich coffee seedlings are the ones which manage to survive and claim a particular patch of land.

This wonder substance is found in a variety of different plant sources including, of course, coffee beans, cocoa beans, tea leaves, kola nuts and guarana berries.

Fortunately, small amounts of caffeine is not harmful to humans, but instead work as a stimulant, making users feel more alert and energised.

Typical use of the drug comes from caffeinated drinks such as coffee and tea, and also soft drinks such as cola and ‘energy drinks’.

Like other stimulant drugs such as cocaine, caffeine in high enough doses can harm and kill.

However, caffeine use is very much safer and more manageable than the use of cocaine and other potent stimulants, and only causes such harm in much more extreme cases.

How does it affect people?

Caffeine works by interrupting natural processes in your brain chemistry which result in you becoming tired and sluggish.

There’s a specific molecule called adenosine which builds up in the central nervous system throughout the day and which binds to special adenosine receptors. This ultimately results in feelings of tiredness.

What caffeine does is block adenosine from binding to the adenosine receptors, thereby increasing alertness.

The absence of the adenosine causes neurons to fire faster, and the process also stimulates the release of dopamine and adrenaline.

In other words, it gives you a boost.

Is caffeine good for you?

Caffeine is a stimulant, so when you drink it, you feel more alert and less lethargic.³

Realistically, caffeine can affect some people more than others, which can depend on how much caffeine you would normally consume.

Caffeine intake is generally considered safe, and there are many health benefits which we will go into below. But it’s more about moderation and how much caffeine you feel comfortable with yourself.

There are advantages and disadvantages that you need to weigh up. Firstly we’ll go through the benefits.

Six benefits of caffeine

We all know that caffeine makes you feel more energetic. The benefits don’t end there, however:

1. Caffeine can boost your athletic performance

Research has shown that caffeine has the potential to seriously increase overall athletic performance.

One 2001 study found that taking caffeine allowed athletes to train with greater intensity, for longer, while experiencing less fatigue as a result.⁴

Other studies found that caffeine significantly reduced post-workout aches and pains over the course of several days.⁵

Further research found that taking caffeine before heading to the gym significantly increased the ability of the test subjects to perform intense strength exercises.⁶

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2. Caffeine improves your mood and boosts mental function

Some research has connected caffeine with positive mood outcomes, including a reduced risk of depression.⁷

This is perhaps not so surprising given the fact that, as mentioned earlier, caffeine causes a spike in dopamine production. Low dopamine levels have been linked with depression.⁸

Another 2014 study linked caffeine consumption with improvements in long-term memory.⁹ Despite these positive studies, more research is needed in this area.

3. Caffeine may protect against disorders like Alzheimer’s disease

Caffeine consumption has been consistently linked to positive health outcomes for a range of mental disorders, including Alzheimer’s disease however more research is needed.

Caffeine appears to reduce inflammation in the brain and prevents the accumulation of the “tau” protein, both of which are closely linked with Alzheimer’s.^10,11

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4. May support your liver

One 2013 study found that coffee may reduce risks of liver damage (cirrhosis) by nearly 84%.

It may slow disease progression, improve treatment response, and lower the risk of premature death.

5. May prevent gout

Studies also suggest that drinking 4 cups of coffee a day may reduce the risk of you developing gout.

For men this is thought to be around 40%, and for women it's around 57%.^12,13

6. May promote gut health

Drinking three cups of coffee a day for three weeks is thought to improve the amount of and the activity of good bacteria in the gut.

Is caffeine bad for you?

Despite the above information, it has to be said that there are some downsides to caffeine and certain things you should be careful of.

According to advice from the NHS, pregnant women should try and limit their caffeine intake.¹⁴ 

They also advise that caffeinated drinks are also unsuitable for toddlers and young children.

Below are listed more drawbacks to caffeine that you should look out for.

Disadvantages of caffeine

Unfortunately, every silver lining has its cloud.

Here are some of the less savoury aspects of caffeine:

• Caffeine boosts cortisol, makes you stressed and anxious

Caffeine is known to significantly boost the levels of the hormone cortisol in the body. Cortisol is one of the primary stress hormones and elevated cortisol levels have long been associated with heightened anxiety.¹⁵

This probably comes as no surprise to anyone who’s ever over-indulged in caffeine. Caffeine-induced “shakes” and “butterflies” are notorious.

• Caffeine is highly addictive

When all is said and done, caffeine is a drug and caffeine addiction can become a very real issue to those who suffer from it.

The more caffeine you consume regularly, the more likely you are to become seriously addicted.

The addiction requires you to consume ever greater levels of caffeine to feel and function “normally” and if you’re forced to go without, withdrawal symptoms can set in.

Symptoms of caffeine withdrawal include:

1. Extreme tiredness
2. Depression
3. Headaches
4. Constipation
5. Muscle cramps
6. Lack of focus

• Heavy caffeine use increases the risk of bone fractures

This may be linked to the elevated cortisol levels, as cortisol is also known to reduce bone density and strength, but whatever the cause, a 2012 meta-analysis found that caffeine increased the overall risk of bone fractures.¹⁵

This risk was dose-dependent, meaning that the more you drink, the more at risk you are.

• Many cause digestive issues

You can rely on the morning cup of coffee to help keep things regular. This laxative effect has been credited to the release of gastrin, a hormone produced by the stomach which is proven to speed up activity in the colon.

This is said to be the same for decaffeinated coffee, so it could be the liquid itself being drawn into the bowel.

However, caffeine itself has been known to stimulate bowel movements by increasing peristalsis, the contractions that move food through your digestive tract.¹⁶

For this reason, it is thought that caffeine may cause activity in the colon, and too much may cause digestive problems.

• May increase blood pressure

Caffeine doesn’t appear to increase the risk of heart disease or stroke in most people.

Although, it has been known to raise blood pressure in numerous studies, which is thought to be down to the stimulatory effect on the nervous system.

This does add an element of risk for heart attack and stroke, which can cause damage over time. Fortunately, though, caffeine’s effect on blood pressure seems to be temporary.

So, there should be an emphasis on paying attention to the dosage and timing of your caffeine intake is important, particularly if you have high blood pressure.

What is too much caffeine?

It’s rare that you would monitor your caffeine intake. However, it’s recommended that you should not exceed more than 300mg per day.¹⁷

However, the average Brit is thought to drink 876 cups of tea a year, which calculates to over 77.5mg of caffeine over that recommended dose.¹⁸

If you were looking to keep track, the NHS has provided this handy information:¹⁹

There is:

• 100mg in a mug of instant coffee
• 140mg in a mug of filter coffee
• 75mg in a mug of tea (green tea can have the same amount of caffeine as regular tea)
• 40mg in a can of cola
• 80mg in a 250ml can of energy drink
• less than 25mg in a 50g bar of plain dark chocolate
• less than 10mg in a 50g bar of plain milk chocolate

What has more caffeine coffee or tea?

This is always one of those questions that come up. But as above, and according to the NHS – a mug of filter coffee has 140mg of caffeine, a mug of instant coffee has 100mg and tea is the lowest with 75mg.

Is caffeine safe for everyone?

Caffeine is considered safe for most adults. You should avoid giving it to toddlers and children.

If you are pregnant, it is thought that you should not exceed more than 200mg of caffeine per day.

However, if you have any concerns about your caffeine intake then you should discuss it with your GP or a health professional.

Last updated: 24 June 2021