Adapted from Authority Nutrition, article by Alina Petre, MS, RD
Each day, billions of people rely on caffeine for a wake-up boost. In fact, this natural stimulant is one of the most commonly used ingredients in the world.
Caffeine is often talked about for its negative effects on sleep and anxiety. However, studies also report its various health benefits.
This article examines the latest research on caffeine and your health.
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 to stay alert and preventing the onset of tiredness.
Historians track the first brewed tea to as far back as 2737 BC. 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.
How Does it Work?
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 being 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.
Caffeine’s main effect is on the brain. It stimulates the brain by blocking the effects of the neurotransmitter adenosine. 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 one hour to reach full effectiveness.
Which Foods and Beverages Contain Caffeine?
Caffeine is naturally found in the seeds, nuts or leaves of certain plants.
These natural sources are then harvested and processed to produce caffeinated foods and beverages. Here are the amounts of caffeine expected per 240 ml of some popular beverages:
Caffeine May Improve Mood and Brain Function
Caffeine has the ability to block the brain signaling molecule adenosine.
This causes an increase other signaling molecules, such as dopamine and norepinephrine
This change in brain messaging is thought to benefit your mood and brain function.
One review reports that after participants ingested 37.5–450 mg of caffeine, they had improved alertness, short-term recall and reaction time. In addition, a recent study linked drinking two to three cups of caffeinated coffee per day to a 45% lower risk of suicide.
Another study reported a 13% lower risk of depression in caffeine consumers.
When it comes to mood, more caffeine is not necessarily better. Indeed, a study found that a second cup of coffee produced no further benefits unless it was consumed at least 8 hours after the first cup. Drinking between three and five cups of coffee per day may also reduce the risk of brain diseases such as Alzheimer’s and Parkinson’s by 28–60%.
It May Boost Metabolism and Speed Up Weight Loss
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 per day. However, a 12-year study on caffeine and weight gain notes that the participants who drank the most coffee were, on average, only 0.4–0.5 kg lighter at the end of the study period.
Bottom Line: Caffeine may boost metabolism and promote fat loss, but these effects are likely to remain small over the long term.
Caffeine 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.
Caffeine may also improve muscle contractions and increase tolerance to fatigue.
Studies report benefits in team sports, high-intensity workouts and resistance exercises.
It may also be able to reduce perceived exertion during exercise by up to 5.6%, which can make workouts feel easier.
Bottom Line: Small amounts consumed about an hour before exercise are likely to improve exercise performance.
Protection Against Heart Disease and Type 2 Diabetes
Despite what you may have heard, caffeine does not raise the risk of heart disease
Recent evidence shows a 16–18% lower risk of heart disease in men and women who drink between one and four cups of coffee each day. One thing to keep in mind is that caffeine may slightly raise blood pressure in some people. However, this effect is generally small and tends to fade for most individuals when they consume coffee regularly.
It may also protect against diabetes. A recent review notes that those who drink the most coffee have up to a 29% lower risk of developing type 2 diabetes. Similarly, those who consume the most caffeine have up to a 30% lower risk.
Bottom Line: Caffeinated beverages like coffee and tea may reduce the risk of heart disease and type 2 diabetes, although this may depend on the individual.
Other Health Benefits
Caffeine consumption is linked to several other health benefits:
Keep in mind that coffee also contains other substances that improve health. Some of the benefits listed above may be caused by substances other than caffeine.
Bottom Line: Drinking coffee may promote a healthy liver, skin and digestive tract. It may also prolong life and help prevent several diseases.
Caffeine consumption is generally considered safe. However some side effects linked to excess intake include anxiety, restlessness, tremors, irregular heartbeat and trouble sleeping. Too much caffeine may also promote headaches, migraines and high blood pressure in some individuals.
Bottom Line: Caffeine can have negative side effects in some people, including anxiety, restlessness and trouble sleeping.
Take Home Message:
Caffeine is not as unhealthy as it was once believed to be.
In fact, evidence shows that it may be just the opposite. Therefore, it’s safe to consider your daily cup of coffee or tea as an enjoyable way to promote good health.