Caffeine: Health Benefits, Side Effects, Risks

Do you feel like a zombie until you’ve had your first cup of coffee? Do you hoard energy drinks and soft drinks with high caffeine levels when studying for college exams? Do you continuously down high caffeinated beverages throughout the day to stay sharp?

80% of the world’s population consumes at least one caffeinated product daily, and this number increases to 90% for adults in North America. As a result, businesses seize the opportunity to churn out all sorts of caffeinated products in energy drinks, traditional coffee and soft drinks.

But what is caffeine, and why is it such an indispensable part of our daily lives?

How Does Caffeine Affect You?

Caffeine is a stimulant that affects our brains and other organs. It is absorbed from the gut to the bloodstream, where it travels to the liver and is broken down into compounds that can affect our organs’ functions.

It can be found naturally in foods such as:

  • Coffee beans
  • Tea leaves and buds
  • Dola nuts
  • Cacao beans
  • Guarana seeds
  • Yerba mate leaf

Health Benefits of Caffeinated Drinks


Now that we know the basics, let’s dive deeper into the effect this chemical has on our bodies.

  1. Increase in Alertness

A small dose (~75mg) may make you more attentive, and a larger amount (160-600mg) may increase your alertness, speed reasoning, and memory.

  1. Fatigue is Reduced

Adenosine is the culprit of making us feel tired. Caffeine binds to adenosine receptors, hence blocks its effects.

  1. Improved Concentration

Caffeine may make you more alert and focused because of the spike in adrenaline levels and brain activity of your neurotransmitters, dopamine and norepinephrine.

  1. Help with Weight Loss

Consuming caffeinated products may cause weight loss as it can suppress your appetite.

  1. May Boost Sports Performance 

Caffeine may boost your sports performance, particularly for endurance and your perceived exertion.

  1. Reduced risks of Alzheimer’s and Parkinson’s disease

Research has shown that lifelong caffeine consumption may lead to a lower risk of Alzheimer’s and Parkinson’s disease.

  1. May Prevent Eyelid spasms

Caffeine may protect against blepharospasm, an eye disorder caused by abnormal brain function that makes you blink non-stop. In severe cases, it can cause blindness.

  1. May Reduce the Risk of Certain Cancers

The possible cancer-related benefits include:

  • Lower risk of skin cancer
  • Decreased risk of mouth, throat, and other cancers
  • Lower risk of endometrial cancer
  • Reduced risk of prostate cancer
  • Lower risk of head and neck cancer
  • Reduced risk of recurrence of breast cancer

How Much is Too Much?

As with all good things, it’s best when it is consumed in moderation.

According to the Food and Drug Administration (FDA) recommends, adults should not drink more than 400mg of caffeine (two to four cups of coffee) per day.

The FDA also cautions against caffeine powder and liquid because the levels of caffeine are too high. To put things into perspective, a single teaspoon of caffeine powder has as much caffeine as about 28 cups of coffee. As a result, consuming caffeine in such amounts can lead to serious health issues and potentially death.

Mixing caffeine with alcohol and drugs is also not a good idea as you do not know how the substances will react. You may also end up drinking more than you anticipated if you mix it with alcohol.

While caffeine is safe for adult consumption, it is not suitable for children. Pregnant women, women trying to get pregnant, and breastfeeding women should consult their health professional before drinking caffeinated beverages. They should also try to reduce their caffeine intake to 200mg or less per day.

Those with caffeine sensitivity may face unpleasant side effects even when they consume less than the recommended daily limit.

Side Effects of Consuming Too Much Caffeine


When you consume too much caffeinated drinks, here are some of the most common adverse side effects that can occur:

  1. Headache

Consuming caffeinated products is a common cause of headache because the blood vessels around your brain narrow when you consume caffeine and enlarge when you stop. This can cause increased blood flow and pressure on surrounding nerves can trigger a headache known as a caffeine withdrawal headache.

  1. Insomnia

Many people consume caffeine to stay awake and alert, but this can interfere with sleep too. Hence, people may find it hard to fall asleep or get deep sleep because the chemical can stay in your system for about five hours.

  1. Nervousness

While caffeine helps you feel alert, it can also make you feel on high alert as it triggers your fight-or-flight response.

  1. Fast heartbeat

Consuming too many caffeinated beverages can change the speed or regularity of your heartbeat. If you think you have an irregular or abnormal heartbeat after drinking caffeine, it is a serious concern, and you should consult your doctor immediately.

  1. Jitters

Caffeine overconsumption can cause physical stimulation that makes you feel jittery. This reaction to stimulant drugs is common and can also make you have rambling thoughts and speech. Hence, people find it hard to relax or calm down after having too many caffeinated drinks.

  1. Muscle tremors

Your muscles may involuntarily twitch as a side effect of high caffeine consumption.

  1. Stomach problems

A multitude of stomach problems can occur when you have too many cups of coffee. As a result, you may feel stomachaches, feeling gassy, heartburn, constipation, diarrhoea, nausea, and vomiting.

  1. Irritability

The combination of these side effects can cause you not to get enough rest, making you feel exhausted and irritable the next day.

Health Risks of Consuming Too Much Caffeine


On top of all the aforementioned negative side effects of coffee, more severe health risks can occur in extreme cases.

  1. Depression

Caffeine can worsen symptoms of anxiety and depression (as seen in the negative side effects) when consumed in large amounts. People who suffer from depression and consume many caffeinated products may also face worse symptoms when they suddenly stop drinking caffeine.

  1. Blood sugar

Your blood sugar levels can rise after consuming certain caffeinated products as it may disrupt your insulin action. Research shows that caffeine can cause a blood sugar level spike in people who have Type 2 diabetes.

  1. Fertility

This study reported that caffeine could decrease muscle activity in the fallopian tubes, which may decrease the chances of getting pregnant.

  1. Pregnancy

Some studies show that drinking more than 300mg of caffeine a day may leaded to delayed fetal growth and abnormal fetal heart rhythm. In severe cases, it may also cause loss of pregnancy.

  1. Frequent urination or inability to control urination

Besides coffee, tea, and energy drinks being liquids, consuming caffeinated products also stimulates your bladder, making you feel a more frequent need to urinate. In the long run, this can also lead to incontinence.

  1. Worsen menopause symptoms

Women who consume caffeinated products during menopause may be more prone to hot flashes and night sweats.

  1. Caffeine Dependence

In serious cases, you can also become physically and psychologically dependant on this chemical. People with this dependency may find it hard to go about their day without coffee.

  1. Caffeine Withdrawal

This dependence can lead to caffeine withdrawal, with symptoms including:

  • Low or bad mood
  • Headaches
  • Nausea
  • Lack of mental clarity
  • Lightheadedness

Do You Know the Caffeine Content in Your Favourite Drinks?

If you love coffee, tea, and energy drinks, chances are, your daily caffeine consumption is pretty high – unless you’re a decaf drinker. Have you ever wondered what the caffeine content in your favourite drinks is?

The caffeine content in drinks can vary due to differences in product, processing, and brewing. If your drink doesn’t come with a label, you can use these numbers as a general guide to the caffeine content in your favourite beverages.


  • Brewed coffee: 96mg per 8oz serving
  • Brewed decaf coffee: 2mg per 8oz serving
  • Espresso: 64mg per 1oz serving
  • Decaf espresso: 0mg per 1oz serving
  • Instant coffee: 62mg per 8oz serving
  • Instant decaf coffee: 2mg per 8oz serving


  • Brewed black tea: 47mg per 8oz serving
  • Brewed black decaf tea: 2mg per 8oz serving
  • Brewed green tea: 28mg per 8oz serving
  • Bottled tea: 19mg per 8oz serving


  • Cola: 22mg per 8oz serving
  • Energy drink: 29mg per 8oz serving
  • Energy shot: 215mg/1oz serving

The Take-Away

Don’t worry. There is no reason to cut coffee out of your life. It usually isn’t a cause for concern when not consumed excessively. Furthermore, drinking caffeinated beverages in moderation can bring several health benefits.

However, you should always take note of caffeine’s adverse side effects and health risks so you know when to cut back if needed.

It is advisable to avoid caffeinated products if you:

  • Are pregnant or breast-feeding
  • Have problems sleeping
  • Have migraines and chronic headaches
  • Have anxiety
  • Have fast or irregular heartbeats
  • Have high blood pressure
  • Are currently on medication
  • Are a child or teenager

The impact of caffeine varies greatly depending on factors such as your size, sex, and sensitivity. You should be aware of your health condition, so you know when something is awry. Want to know if you’re sensitive to caffeine? Use the promo code “CIRCLE25” to get a 25% discount on CircleDNA kits.

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