Caffeine Benefits & Side Effects

Caffeine is one of the world's most widely used stimulants. It's a bitter but ubiquitous substance taken in coffee, tea, soft drinks and certain kinds of medications. As an active substance, caffeine affects your body's metabolism and central nervous system. Known for revving up your level of alertness, caffeine also has protective value for many health conditions, including diabetes and liver illnesses. You can get dependent on caffeine, an effect you might have the misfortune of experiencing through painful withdrawal symptoms. Moderation is key when it comes to consuming caffeine.

Caffeine Consumption in the United States

Found in the leaves, seeds and fruits of at least 63 plants, caffeine is a popular ingredient used the world over. The Johns Hopkins Bayview Medical Center estimates that between 80 percent and 90 percent of adults and children in North American regularly consume some caffeine. In the United States alone, adults on average ingest about 280 mg daily. That's equivalent to about 17 oz. of brewed coffee or 84 oz. of a caffeinated soft drink. According to University of Utah University Health Care, some 20 percent of Americans consume more than 500 mg per day, and 10 percent consume more than a gram, or 1,000 mg of caffeine daily.

Benefits of Caffeine

You probably down that first cup of morning Joe to get your day started. Indeed, the most commonly cited benefit of caffeine is its ability to make you more alert, improve your concentration and boost your energy. It also can improve your physical performance. For example, caffeine can increase muscular endurance, which is probably why it's such a popular ingredient in over-the-counter weight loss and energy supplements. Caffeine also is used to treat conditions, such as headaches and migraines, to temporarily relieve fatigue and drowsiness. In a review of the literature on the health effects of caffeine in "IFIC Review," the International Food Information Council Foundation reported that caffeine might help reduce risk of several chronic diseases, such as diabetes, Parkinson's disease, liver disease and colorectal cancer. In addition, as an antioxidant, caffeine also might improve your immune function.

Side Effects of Caffeine

Too much caffeine can make you jittery, restless, anxious and irritable. Too much caffeine can cause insomnia and poor sleeping and induce headaches and abnormal heart rhythms. Excessive amounts of caffeine in your diet might make you have to go to the bathroom a lot more often than normal. In some people, too much caffeine might cause nausea, anxiety, depression and tremors. Although no conclusive statements have been made, the National Library of Medicine says public health officials have long studied the role of caffeine in health problems like fibrocystic bread disease, coronary heart disease, birth defects, miscarriage and child development.

Caffeine Addiction and Withdrawal

Another side effect of caffeine intake is your ability to get hooked on the substance, which in turn causes severe symptoms when you stop taking it. Caffeine, "in the context of adrenaline and dopamine production," provides senses of "lift and pleasure," according to a paper published by Harvard Law School. As caffeine metabolizes, adrenaline and dopamine diminish, causing fatigue, depression and a craving for another dose. The cycle of repeated caffeine intake is called caffeinism, and can lead to adrenal fatigue. When you try to stop, you might endure withdrawal. As your caffeine levels drop, your blood vessels dilate, causing headaches as excess blood flows into your brain. You also might experience severe drowsiness and mood disturbances as you come off of caffeine.