Approximately 90% of Americans consume coffee on a daily basis, with more than half of all adult Americans consuming more than 300 milligrams of caffeine daily. Surprisingly though, it's not America but Scandinavian nations, such as Finland, that consume more caffeine per capita than any other country. Being present in so many things, including tea, chocolate, soft drinks, and coffee, and consumed by so many people, it is important that we understand what caffeine is. Caffeine is a naturally occurring drug that affects the body's metabolism in a variety of ways and stimulates the nervous system. It is the world's most popular psychoactive drug.

This chemical stimulant, called trimethylxanthine, shares several traits with other familiar drugs, both legal and illegal. It's known for giving people a boost of energy and making them more alert. When in its pure form, caffeine is a crystalline powder with a very bitter taste. It can stimulate the heart and serves as a mild diuretic, meaning that it increases urine production, flushing fluid out of the body. Most people are comfortable consuming caffeine without much thought, likely because it is naturally present in so much food and drink. It is naturally in coffees and teas, though it's often refined and added to energy drinks and soft drinks, as well as other foods and beverages.

History of Caffeine Consumption

Caffeine has been a part of global culture for thousands of years, with African folklore citing the discovery of coffee's energizing properties sometime around 800 AD. Since the drug occurs naturally in a variety of plants all over the world, such as in coffee beans, cocoa beans, and tea leaves, we started consuming caffeine in a wide range of edibles early on in several cultures. In China, for instance, tea was drunk as early as 200 BC. In European countries, coffee and chocolate were often considered a luxury, but today these items are widely available in the Western world and used to heighten alertness.

Caffeine And Medicine

While it's found in nature, caffeine is still a drug. There are a number of situations in which it can be used medically. For instance, caffeine is often found in weight-loss pills, as it can help boost metabolism. Citrated caffeine, which has been treated with a citrate of sodium or potassium, can help premature babies and young children with breathing problems. It can improve the effectiveness of other medications, such as acetaminophen and aspirin, and is commonly added to certain over-the-counter pain relievers. As a drug, the substance has been studied for potentially having benefits in fighting Alzheimer's disease, Parkinson's disease, and cancers. Some research has suggested that people who consume caffeine on a daily basis may be less likely to contract diabetes.

How It Works

To understand how caffeine works, you need to understand adenosine. Adenosine is a chemical manufactured by neurons, which binds to its own adenosine receptors and steadily builds up throughout the day. When adenosine connects with its receptors, it causes drowsiness, leading the nerve-cell activities to slow down while also causing blood vessels in the brain to dilate. Caffeine tricks the receptor nerve cells because its shape is so similar to adenosine. Like a sneaky impersonator, caffeine will bind to the adenosine receptors, lodging itself there and blocking the body's natural adenosine from attaching itself. With caffeine is taking up all of adenosine's spots, the body essentially stops telling itself to get tired. In addition to blocking the "tiredness" chemicals, caffeine also lets "party" chemicals like dopamine and glutamate in. That's where the energy comes from.

Meanwhile, the pituitary gland senses all of the activity, causing it to think there is some type of emergency, and releases hormones that stimulate the adrenal glands, which then produce adrenaline. After drinking a large amount of coffee, your heart may beat faster and you may feel excited as a result. When one "crashes," it's because the adenosine has continued to build and build in the background, with nowhere (not enough open receptors) to land. Caffeine also causes blood vessels in the brain to constrict because its chemicals are blocking the ability of adenosine to open them up. This is why many headache medicines contain caffeine, as it constricts blood vessels which can aid in stopping a vascular headache.

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