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j Java: health: morning coffee isn't just for Mom and Dad anymore. But is it good for you?

ZZ Quinn, 15, is a real coffee addict. "I usually drink a mug of coffee in the morning and probably four or five grande Starbucks cups throughout the day," says the freshman at Mercer Island High School near Seattle, Washington. She's just one of the many students who starts her day with a cup of joe from the school's in-house coffee stand. "The lines for coffee are really, really long in the morning," says classmate Suzy Myre, 15. "You have to get there early if you want to get your coffee before class."

These caffeine-crazed high-schoolers aren't alone. According to the National Coffee Association, more than 108 million Americans, or 51 percent of the country's population over the age of 18, rely on the brewed concoction to jump-start their day. All told, the world drinks about 600 billion cups of coffee a year!

And no wonder: Caffeine is a powerful stimulant. It delivers a chemical jolt to the central nervous system (CNS, the network that includes the nerves, spinal cord, and brain) that makes you feel alert--perfect for cramming the night before a big test, for example.

But it's easy to forget that caffeine is a drug that can cause a pounding heart, anxiety, sleeplessness, and in high doses (on the order of 100 cups of coffee downed in rapid succession), even death. "In normal doses, caffeine's side effects shouldn't even be compared to the serious effects of other stimulants, such as cocaine, heroin, and ecstasy," says addiction expert Bruce Goldberger of the University of Florida. "But people should be aware of how much caffeine they consume and how it affects them." Read on to see how caffeine works its magic. Then decide for yourself: How does caffeine affect you?


Caffeine is a molecule that some plants, like coffee and tea, produce to poison leaf-munching pests. Farmers harvest a coffee plant's seeds or "beans" from the plant's berries. And we roast, grind, and brew the beans, and drink their natural pesticide in the steamy brown liquid called coffee.

Within 15 minutes of your first sip, every cell in your body has absorbed the drink's caffeine. From here the drug "affects all your major systems: circulatory (heart and blood vessels), respiratory (heart and lungs), renal (kidneys and bladder), and the CNS.

Like other stimulants, caffeine does most of its work in your brain. Here, it interferes with adenosine, a chemical made by all cells when they burn sugar for energy. As your energy reserves dive, adenosine builds up in your body. It binds to your cells and makes you feel drowsy (see diagram, below). "Adenosine puts on the brakes: It signals that it's time to sleep," says Professor James Lane of Duke University. When caffeine is around, adenosine can't bind to your cells. "Caffeine disconnects the brakes so the nerve cells keep running," he says.

Caffeine doesn't give you more energy. It just keeps your body from getting the message that you're sleepy. "Caffeinated drinks are not a substitute for not getting enough sleep," says nutritionist Althea Zanecosky, of the American Dietetic Association. Bottom line: A good night's sleep does more to improve your mood, energy level, and alertness than any amount of caffeine.


Students enjoy caffeine because it gets them wired: "After my coffee I feel really hyper," ZZ says, "I feel like I can stay more focused in class." And at least one recent study has shown that college students who consumed moderate amounts of caffeine while studying and taking a test had improved concentration and performed better on their tests. It can "also improve athletic performance in endurance sports. "When you get an adrenaline rush it's about the same as when you get caffeine," says Zanecosky.

The problem: "Relatively high doses of caffeine will produce a bunch of symptoms that are just like an anxiety or panic attack," says Lane. "It's a condition called caffeinism." Symptoms include insomnia, nervousness, irregular heartbeat, and tremors. And consistently gulping over 100 milligrams of caffeine a day, or the amount in about one cup of coffee, can create an addiction (dependence on a chemical not naturally produced by the body).

Scientists don't know how caffeine affects health over the long term. But Lane's latest research suggests that even in small doses, the drug exaggerates your mood. "Being a teen has a lot of pressures--social, school, or family life. And caffeine probably makes all of these pressures more intense," says Lane.


Pediatricians and other health experts recommend that teens keep caffeine consumption to around 100 mg or less a day, or about the amount of caffeine in one cup of coffee or two sodas (see graph, p. 15). However, everyone's body reacts to caffeine differently. For example, some teens can drink a soda before going to bed while the same drink would keep others up all night. "It doesn't really bother me to drink coffee at night," says Ross Dillingham, 15, who regularly downs three mochas a day.

How can you tell if you're getting too much caffeine? "Caffeine is bad if the arousal it produces interferes with your life," says Lane. "If you can't sleep or it makes you anxious or irritable, you should moderate how much you drink." One simple way to cut back is to skip refills at the soda fountain or order decaf at the coffee bar. And when you feel like a big cup of coffee, "check out why you're turning to caffeine," advises Zanecosky. "If you think you're tired, you might just be dehydrated or hungry." Or you might just need a good night's sleep!

It's Your Choice

1 Doctors recommend that teens limit their daily caffeine consumption to:

A 100 milligrams.

B 100 grams.

C 400 milligrams.

D 400 grams.

2 Which of the following best describes Lane's advice:

A Teens should never consume caffeine.

B Teens should stop consuming caffeine when they start to shake uncontrollably.

C Teens should be aware of how much caffeine they consume.

D Teens are getting too much caffeine if it interferes with sleep or causes anxiety.

3 Which of the following is not a symptom of caffeinism:

A anxiety

B irregular heartbeat

C sleepiness

D tremors


Caffeine has a similar chemical structure to adenosine, a sleep-inducing molecule produced naturally by your body. See how caffeine interferes with adenosine to perk you up.


When your body's energy reserves are low, adenosine binds to special receptors on the cell surface. It causes the cells to shut down and you begin to feel sleepy.


Since caffeine's structure is similar to adenosine's, it also fits the receptor. Adenosine-can't bind, so you stay alert.
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Author:Tucker, Libby
Publication:Science World
Date:Feb 2, 2004
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