There’s a drug that has become integrally entwined with our history, culture, and everyday life: caffeine. Sure, most of us start our day with a cup of it in one form or another. And some drink it religiously – some of us more literally than others. But what effects does caffeine have on our bodies?
Caffeine is a naturally occurring stimulant found in many plants, including coffee beans, tea leaves, and cacao pods. It is the world's most widely consumed psychoactive substance, present in many beverages and foods, so it’s important to be aware of its potential effects on us.
When consumed, caffeine is quickly absorbed into the bloodstream and travels to the brain, where it blocks the action of a neurotransmitter called adenosine. Adenosine is responsible for promoting sleep and reducing arousal in the brain, and its inhibition by caffeine leads to increased alertness and wakefulness.
Caffeine also triggers the release of other neurotransmitters, such as dopamine and norepinephrine, which enhance mood, increase heart rate and blood pressure, and stimulate the central nervous system. These effects can improve physical performance, increase focus and attention, and elevate mood.
However, caffeine can also have negative impacts, such as anxiety, jitteriness, and insomnia. These are more likely to occur in people who consume large amounts of caffeine, have underlying health conditions, or are particularly sensitive to the substance.
Civet coffee, consisting of coffee cherries that have been defecated by the Asian palm civet cat, is one of the most expensive coffees in the world, with retail prices reaching US$1,300 per kilogram.
In addition to its effects on the brain, caffeine can also impact other systems in the body. It has been shown to increase the production of stomach acid, which can lead to digestive issues such as heartburn and stomach ulcers. The fact that it can increase urine production makes sense, given that caffeine is usually brewed with water, but you might be surprised to learn that it can also cause dehydration if consumed in large amounts.
While the general effects described here are common for many of us, there’s no “one size fits all” description of how we react to the stimulant. The effects of caffeine vary depending on an individual's sensitivity, the amount consumed, and the rate and timing of consumption.
Whether a “cup of joe” is your morning ritual, or ingesting caffeine is an all-day binge for you, now at least you can sip your next cup knowing a little more about the fuel that helps get you through your day.