What is Caffeine?
Caffeine is a naturally occurring compound found in plants including coffee, tea, cocoa, and guarana. Most caffeine is consumed in the drinks made from these plants, but is also added to energy drinks, diet supplements, medications.
Many people consume caffeine for its stimulating effects, which increase energy and alertness, and reduce drowsiness. Caffeine has other short term effects on the body including reduced appetite, increased metabolism, nervousness, insomnia and stomach upsets. Long-term effects of caffeine consumption include a reduced risk of diseases, an increased risk of osteoporosis in women, and bladder problems.
Why Does Coffee Have Caffeine?
Coffee has caffeine because there is caffeine in the beans that it is made from. Coffee plants have caffeine in order to protect themselves from predators and other plants, but also to attract pollinators. Caffeine is toxic to insects and small herbivores and deters these animals from eating the plant. When coffee leaves fall on the ground, the caffeine is absorbed into the soil, preventing competing plants from growing nearby. The caffeine in coffee flowers also causes addiction in pollinating insects such as bees, helping to spread the cultivation of the plant.
Decaffeinated coffee contains up to 97% less caffeine than regular coffee, but it is not completely caffeine-free. Decaf coffee contains around 5 mg caffeine per 6 oz (177 ml) cup, compared to regular coffee, which contains around 72 mg caffeine per 6 oz (177 ml) cup.
To create decaffeinated coffee, the caffeine must be removed from the green coffee beans by Swiss water processing, treatment with chemical solvents, or treatment with CO2. There is no coffee that is naturally free from caffeine.
What Does Caffeine Do to the Human Body?
Caffeine acts as a stimulant on the human body’s central nervous system, creating both positive and negative effects.
The most common short-term effect of caffeine on the human body is its ability to reduce drowsiness and increase mental alertness. This is the reason that most people drink coffee first thing in the morning. Caffeine can also improve athletic performance by increasing energy and delaying the onset of fatigue. Caffeine can reduce appetite and increase the energy used for digestion, which can help with weight loss.
Negative short-term effects of caffeine include nervousness, headaches, confusion, stomach irritability, sleeping problems, increased blood pressure, increased urination, and heartburn. Caffeine withdrawal may cause short-term effects such as headaches, irritability, and muscle aches.
Positive long-term effects of caffeine consumption include a decreased risk of suicide, a decreased risk of developing Alzheimer’s and Parkinson’s disease, and possibly an improved memory.
Negative long-term effects of caffeine include issues during pregnancy, bladder instability, an increased risk of osteoporosis, and worsening of symptoms of anxiety and depression.
Is Caffeine Healthy?
Yes, caffeine is healthy as long as it’s consumed in the correct amounts. Caffeine has many benefits for your health including a reduced risk of diseases. The benefits of caffeine are due to the stimulating effect it has on the body’s nervous system.
Caffeine consumption has been shown to reduce the risk of depression and Parkinson’s disease. Both of these conditions are linked to low dopamine levels in the brain. Caffeine does not increase dopamine but makes your brain more sensitive to dopamine, as well as providing protective benefits for dopamine receptors.
Caffeine reduces the risk of colon cancer by speeding up digestion. An increased bile production means that colon tissue spends less time in contact with carcinogens found in food.
Caffeine can also be used to aid in weight loss. The stimulating effect increases your metabolism, helping you to burn more calories.
It’s important to note that some of the pros and cons of coffee are not due to caffeine. One example is antioxidants, which are found in both regular and decaffeinated coffee. Antioxidants neutralise harmful free radicals in the body, helping to prevent diseases such as cancer and slow the aging process.
For information on a safe daily caffeine intake, read our guide to how much caffeine is too much.
Is Caffeine Bad for Your Kidneys?
Yes, caffeine is bad for your kidneys because it increases stress on the kidneys and increases the list of kidney stones, However, caffeine can also have some beneficial effects against chronic kidney disease (CKD).
Caffeine has a stimulating effect on the central nervous system which creates increased blood pressure. This causes the kidneys to work harder, placing them under continued strain. High levels of caffeine have also been linked to kidney stones. There is another compound in coffee known as oxalates that can increase the risk of kidney stones. Oxalates are found in both caffeinated and decaffeinated coffee.
One study has shown that caffeine consumption can actually reduce the risk of developing chronic kidney disease as well as prolong the life of people with chronic kidney disease. This benefit is thought to be due to the fact that caffeine can improve vascular function. For people with CKD that are on a fluid-restricted diet, the benefits of caffeine will need to be balanced with the additional fluid intake when drinking coffee.
Related: What are the harms of coffee?
Is Caffeine Bad for Your Brain?
Yes, caffeine is bad for your brain if consumed in large amounts, but when taken in moderation it can have positive effects.
Caffeine acts as a stimulant on the brain, which increases brain activity. In small amounts, this can improve alertness and energy, but in large amounts, it can cause confusion as the brain becomes overstimulated. Other short-term effects on the brain include increased anxiety, insomnia, and headaches. One study has shown that drinking more than six cups of coffee per day over extended time periods can shrink the size of the brain.
When consumed in moderation, caffeine is safe and can even have benefits for brain health. In the short term, caffeine increases mental performance and short-term memory by stimulating brain activity. In the long term, caffeine can reduce the risk of depression, and reduce the risk of degenerative brain conditions such as Alzheimer’s and Parkinson’s disease.
Related: Nootropic coffee
What is Caffeine Made Of?
Caffeine is made of carbon, nitrogen, hydrogen, and oxygen atoms, with the chemical formula C8H10N4O2. These atoms are arranged in heterocyclic rings to form a purine alkaloid.
When metabolized by the body, the caffeine molecule breaks down into three different compounds: Paraxanthine, Theobromine, and Theophylline. Paraxanthine is a nervous system stimulant and is believed to help improve short-term memory and response times and protect against neurodegeneration. Theobromine is a mild stimulant and reduces blood pressure by dilating the blood vessels. It can also cause sweating, headaches, and nausea. Theophylline opens the air passages in the lungs and can be used to treat symptoms of respiratory issues including chronic bronchitis, emphysema, and asthma.
How Much Caffeine Does One Cup of Coffee Have?
The amount of caffeine in one cup of coffee will vary depending on the brewing method, the type of coffee beans used, and the serving size of the coffee.
Espresso coffee has the highest concentration of caffeine with 2240-2730 mg/L but is consumed in smaller serving sizes. A standard 1 oz (30 ml) shot of espresso contains 70-80 mg of caffeine.
Regular drip coffee has a caffeine concentration of 680-740 mg/L but is consumed in larger servings. A standard 8 oz (236 ml) cup of regular coffee contains 115-175 mg of caffeine.
Decaffeinated coffee does contain some caffeine but at much lower concentrations. A standard 8 oz cup of decaf coffee contains 2-4 mg of caffeine.
Some of the strongest coffee beans are sourced specifically for their high caffeine content and contain much higher concentrations of caffeine than regular beans. For example, an 8 oz cup of regular coffee made with Death Wish coffee beans contains 430-485 mg of coffee.
Can Caffeine Make You Feel Awake?
Yes, caffeine can make you feel awake. This stimulating effect is one of the most common results of consuming caffeine.
Caffeine keeps you awake by blocking the activity of adenosine, a chemical compound that promotes sleep. Adenosine builds up in the body during the course of the day and attaches itself to receptors in the brain. When the levels of adenosine reach a certain threshold, you begin to feel drowsy. Caffeine stops the adenosine from attaching to the receptors in the brain and prevents the feeling of drowsiness.
Who Should Not Consume Caffeine?
People who should not consume caffeine include pregnant women, children, and people with heart conditions, anxiety, insomnia, or irritable bowel syndrome.
Pregnant women or women who are trying to get pregnant should avoid caffeine or at least limit their intake to 200 mg per day. Caffeine can increase the risks of miscarriage, premature birth, and underweight babies.
Children under 12 are more susceptible to the negative side effects of caffeine. Even small amounts of caffeine can cause hyperactivity, anxiety, an increased heart rate in children, as well as affecting their sleep schedule.
Caffeine’s stimulatory effects can increase the symptoms of heart conditions including arrhythmias, anxiety and panic attacks, insomnia and irritable bowel syndrome, or other stomach upsets.
Can Caffeine Make You Gain Weight?
No, caffeine alone can not make you gain weight, in fact, it is sometimes used to aid with weight loss. Caffeine is sometimes added to weight loss supplements.
Caffeine can help with weight loss in two ways: by increasing energy expenditure and reducing energy intake. The stimulating effect of caffeine can increase your resting metabolic rate (RMR) by 3-11%, so you burn more calories even without any additional activity. Caffeine decreases the levels of ghrelin, the hormone responsible for hunger. A single cup of coffee a day can temporarily reduce your appetite and increase feelings of fullness.
The reason some people may gain weight when consuming large amounts of caffeine is the way that they are consuming it. Many caffeinated drinks such as iced coffees or energy drinks can be very high in calories due to the sugar and fat content.
Is Caffeine Addictive?
Yes, caffeine is addictive, but caffeine use is scientifically considered a dependence and not an addiction.
Caffeine’s addictive properties are due to the way that it changes your brain chemistry. Once absorbed into the bloodstream, caffeine blocks adenosine receptors in the brain. This has the effect of stimulating your body’s production of natural stimulants including dopamine and norepinephrine. Prolonged consumption of caffeine prompts the body to create more adenosine receptors in the brain, requiring increased levels of caffeine to receive the same levels of stimulation.
Caffeine dependence can cause withdrawal symptoms in the absence of caffeine. Symptoms include headaches, muscle aches, fatigue, nausea, and mental fog. Symptoms normally dissipate within 7-12 days.
Can Caffeine Affect Your Memory?
Yes, it’s possible that caffeine can affect your memory, but more research is needed. Different studies show conflicting results about whether caffeine’s effect on memory is positive or negative, or if it has no impact at all.
A study conducted by Johns Hopkins in 2014 showed that caffeine had a positive impact on long-term memory. Participants were shown a series of images, then given a caffeine tablet or a placebo. Those who were given caffeine were better able to recognise the images after 24 hours.
Researchers at Pusan University found that long-term consumption of low doses of caffeine would have a negative effect on memory. The 2007 experiment found that caffeine slowed hippocampus-dependent learning and impaired long-term memory.
An earlier study from the University of South Dakota conducted in 1987 showed mixed results according to gender. When asked to memorise a list of words, male participants showed no difference in recall ability when given caffeine, but female participants had an impaired recall ability when given caffeine.
What are the Benefits of Caffeine?
Caffeine has many benefits in both the short term and long term, including increased energy and a decrease in your risk of disease.
Some of the benefits of caffeine are:
- Increased alertness – caffeine blocks the activity of adenosine, a chemical in the brain that makes you feel drowsy.
- Increased energy – caffeine triggers the release of adrenaline, which increases your heart rate and delivers more blood to your muscles.
- Aids weight loss – caffeine increases your metabolic rate to help you burn energy.
- Reduced risk of depression – caffeine makes your brain more receptive to dopamine, a mood-elevating chemical.
- Reduced risk of Parkinson’s disease – caffeine has a protective effect on dopamine receptors. Low dopamine is linked to the development of Parkinson’s.
- Reduced risk of Alzheimer’s disease – caffeine blocks adenosine receptors in the brain, which are linked to brain dysfunction and disease.
- Reduced risk of colon cancer – caffeine speeds up the digestive process, so that colon tissue has reduced contact with carcinogens.
- Increased longevity for sufferers of chronic kidney disease – caffeine improves vascular function, which reduces the risk and severity of CKD.
What Are the Drinks That Have the Highest Caffeine Amount?
The drinks that have the highest caffeine amount are energy shots, energy drinks, and sodas, which contain added caffeine. Drinks that are naturally high in caffeine are coffee, tea, yerba mate, and cocoa.
Drinks with the highest caffeine content per fluid ounce are:
- Energy shots: Up to 310 mg / fl oz (30 ml)
- Espresso coffee: 70 mg / fl oz (30 ml)
- Energy drinks: Up to 39.5 mg / fl oz (30 ml)
- Regular coffee: 20 mg / fl oz (30 ml)
- Sodas: Up to 7.4 mg / fl oz (30 ml)
- Black tea: 5.3 mg / fl oz (30 ml)
- Yerba mate: 5 mg / fl oz (30 ml)
- Cocoa: 5 mg / fl oz (30 ml)
- Green tea: 2.2 mg / fl oz (30 ml)
This list refers to the concentration of caffeine in each fluid ounce, and not the total amount of caffeine consumed when drinking these beverages. For the total amount of caffeine, you will need to refer to the serving size. For example, a regular espresso shot contains 70 mg of caffeine, but an 8 oz can of energy drink could contain up to 316 mg of caffeine.
Is Pure Caffeine Legal?
No, pure caffeine is not legal for sale to consumers in the United States. However, the possession of pure caffeine is legal.
In 2018, the US Food and Drug Administration (FDA) issued a guidance to ban the sale of concentrated caffeine in liquid or powder form. This applies to packages or bottles containing multiple doses of caffeine, where the consumer is required to measure each dose.
Concentrated caffeine products that are not affected by the ban include foods and drinks, over-the-counter medication, and concentrated caffeine products that are pre-portioned such as tablets or capsules.
What is the Color of Pure Caffeine?
Pure caffeine is a white crystalline powder. It has a very bitter taste, but no smell.
Pure caffeine in this form must be extracted from natural sources such as coffee or guarana, or synthetically produced.
What are the Long-Term Effects of Caffeine?
The long-term effects of caffeine consumption can be both positive and negative.
The positive long-term effects in caffeine consumption are disease prevention and longevity. Caffeine can reduce the risk of depression, Alzheimer’s disease, Parkinson’s disease, and colon cancer.
The negative long-term effects of caffeine include issues during pregnancy, bladder instability, an increased risk of osteoporosis in post-menopausal women, chronic insomnia and worsening of symptoms of anxiety.
Some studies have shown that long-term consumption of caffeine, even in small doses, can have a negative impact on memory. However, there are conflicting studies that show caffeine improves long-term memory.