Gaby
For many people, the urge for a cup of coffee is the main reason to crawl out of bed in the morning. What gives this aromatic drink so much power over us? How harmful or helpful is it, really?
The Secret Weapon
First and foremost, like morphine and nicotine, caffeine is an alkaloid. That helps explain our attachment to coffee. Ancient peoples discovered that plants containing caffeine provided energy and a clear stimulating effect.
When we think of caffeine sources, coffee is the first thing that comes to mind. But caffeine is also found in tea, yerba mate, cocoa, the flowers of citrus trees like lemon, orange, and grapefruit, and in camellia. In total, botanists identify around 200 species of such plants.
The natural role of caffeine in plants was a mystery for a long time. In the 1980s, researchers at Harvard discovered that plants use caffeine as a natural pesticide. In concentrated doses, it can kill insects within hours. Under its influence, insect behavior changes, appetite decreases, and reproduction is suppressed in tobacco worms, milkweed beetles, moth larvae, and mosquitoes.
This raises the question: if caffeine can be lethal to insects, does it harm the human body?
The Dark and Light Sides of Caffeine
Both the positive and negative effects of caffeine come from how it acts on the nervous system and the brain. Among the benefits are:
- Stimulates and Energizes
Caffeine blocks adenosine receptors in the brain. Adenosine normally slows brain activity and signals tiredness, so blocking it makes you feel more alert. - Increases Endurance
Caffeine changes how muscles use glycogen, letting them work longer before fatigue sets in. - Improves Mood
A cup of coffee boosts dopamine levels, which can improve mood. - Relieves Pain
Caffeine can help block certain pain pathways and enhance pain relief.
The negative effects of caffeine depend on dose and individual sensitivity.
Insomnia
Drinking large amounts of coffee throughout the day can interfere with sleep at night and lead to chronic insomnia.
Tremors
In some people, caffeine can cause hand tremors.
Headaches
Because caffeine can cause mild dependence, cutting back may trigger withdrawal symptoms such as headaches.
Increased Blood Pressure
Caffeine metabolism releases stress hormones that can raise blood pressure.
Exacerbation of Cardiovascular Diseases
Because caffeine increases the force and rate of heart contractions, it can be risky for people with certain heart conditions.
Anxiety.
Caffeine can heighten anxiety, especially in people with anxiety disorders or during stressful situations.
Reduce or eliminate coffee consumption if you experience negative side effects from caffeine.
In one form or another, over 80% of the world’s population consumes caffeine—making it the most widely used psychoactive substance on the planet.
How Much Coffee is Too Much?
Safe caffeine limits vary with sensitivity, weight, age, and health. Here are general guidelines to follow.
Healthy adults can safely consume 300–400 mg of caffeine per day. That is roughly equivalent to about 5.5 cups of espresso made with 7–11 grams of ground coffee and 25–35 milliliters of water. Pregnant women should limit themselves to no more than 200 mg per day.
For teenagers aged 13–18, doctors recommend no more than 100 mg of caffeine per day. Children under 12 should limit their intake to no more than 3 mg per kilogram of body weight. Although children rarely drink coffee, watch the caffeine content in sugary sodas and energy drinks, which is usually listed on the label.
In recent years, several teenage deaths have been linked to caffeinated energy drinks, prompting doctors to call for restrictions on the sale of energy drinks and other high-caffeine products to children. In many countries, selling caffeine in the form of dietary supplements is also prohibited.
An Unexpected Turn
Just a few decades ago, medical professionals warned that coffee might increase cancer risk. After years of research, the World Health Organization removed coffee from its list of potential carcinogens in 2016. Why the change? Early studies often failed to account for other factors: coffee drinkers were more likely to be smokers and to lead sedentary lifestyles.
When newer studies adjusted for those factors, they sometimes found an association between coffee consumption and lower mortality. Besides caffeine, coffee contains antioxidants and other active compounds that may reduce internal inflammation and protect against disease.
Cancer.
A growing body of research suggests coffee’s antioxidant properties may help lower the risk of certain cancers. Coffee drinkers appear less likely to develop melanoma, cancers of the oral cavity, uterine and prostate cancer, brain cancer, and colorectal cancer.
Type 2 Diabetes.
Many studies show that regular coffee drinkers process glucose more effectively, which reduces the risk of developing type 2 diabetes.
Neurological Diseases.
Regular daily caffeine consumption, even from tea, is associated with a lower risk of Alzheimer’s and Parkinson’s disease.
Liver Disease.
Coffee appears to protect against liver cirrhosis in people with alcohol-related liver damage or fatty liver disease.
Depression.
The pleasure of a creamy cappuccino or strong espresso can improve mental well-being. Several studies find that coffee drinkers have a lower risk of depression.
Recent research suggests that, in moderation, coffee can bring pleasure and also deliver health benefits.
People with poor diets and harmful habits like smoking and excessive alcohol use are unlikely to reap coffee’s potential health benefits.
