What is caffeine?
Caffeine is a natural stimulant most commonly found in tea, coffee, and cacao plants.
It works by stimulating the brain and central nervous system, helping you stay alert and prevent the onset of tiredness.
Historians track the first brewed tea as far back as 2737 B.C.
Coffee was reportedly discovered many years later by an Ethiopian shepherd who noticed the extra energy it gave his goats.
Caffeinated soft drinks hit the market in the late 1800s and energy drinks soon followed.
Nowadays, 80% of the world’s population consumes a caffeinated product each day, and this number goes up to 90% for adults in North America.
How it works
Once consumed, caffeine is quickly absorbed from the gut into the bloodstream.
From there, it travels to the liver and is broken down into compounds that can affect the function of various organs.
That said, caffeine’s main effect is on the brain.
It functions by blocking the effects of adenosine, which is a neurotransmitter that relaxes the brain and makes you feel tired.
Normally, adenosine levels build up over the day, making you increasingly more tired and causing you to want to go to sleep.
Caffeine helps you stay awake by connecting to adenosine receptors in the brain without activating them. This blocks the effects of adenosine, leading to reduced tiredness.
It may also increase blood adrenaline levels and increase brain activity of the neurotransmitters dopamine and norepinephrine.
This combination further stimulates the brain and promotes a state of arousal, alertness, and focus. Because it affects your brain, caffeine is often referred to as a psychoactive drug.
Additionally, caffeine tends to exert its effects quickly.
For instance, the amount found in one cup of coffee can take as little as 20 minutes to reach the bloodstream and about 1 hour to reach full effectiveness.
May improve mood and brain function
Caffeine has the ability to block the brain-signaling molecule adenosine.
This causes a relative increase in other signaling molecules, such as dopamine and norepinephrine. This change in brain messaging is thought to benefit your mood and brain function.
May boost metabolism and fat burning
Because of its ability to stimulate the central nervous system, caffeine may increase metabolism by up to 11% and fat burning by up to 13%.
Practically speaking, consuming 300 mg of caffeine per day may allow you to burn an extra 79 calories daily.
May enhance exercise performance
When it comes to exercise, caffeine may increase the use of fat as fuel.
This is beneficial because it can help the glucose stored in muscles last longer, potentially delaying the time it takes your muscles to reach exhaustion.
Coffee consumption is linked to several other health benefits:
- Liver protection. Coffee may reduce the risk of liver damage (cirrhosis) by as much as 84%. It may slow disease progression, improve treatment response, and lower the risk of premature death.
- Longevity. Drinking coffee may decrease the risk of premature death by as much as 30%, especially for women and people with diabetes.
- Decreased cancer risk. Drinking 2–4 cups of coffee per day may reduce liver cancer risk by up to 64% and colorectal cancer risk by up to 38%.
- Skin protection. Consuming 4 or more cups of caffeinated coffee per day may lower the risk of skin cancer by 20%.
- Reduced MS risk. Coffee drinkers may have up to a 30% lower risk of developing multiple sclerosis (MS). However, not all studies agree.
- Gout prevention. Regularly drinking 4 cups of coffee per day may reduce the risk of developing gout by 40% in men and 57% in women.
- Gut health. Consuming 3 cups of coffee a day for as few as 3 weeks may increase the amount and activity of beneficial gut bacteria.
Keep in mind that coffee also contains other substances that improve health. Some benefits listed above may be caused by substances other than caffeine