Get the 'buzz' on caffeine
Get the 'buzz' on caffeine Legend maintains that Shen Nung, an ancient Chinese emperor, accidentally brewed the first pot of tea when he failed to notice that leaves from a nearby bush landed in a pot of water he was boiling. The result may have been the world's first caffeinated drink.Since then, we've discovered caffeine occurring naturally in 63 plants across the world. The result is our collective caffeine habit. The average American adult consumes about 200 milligrams of caffeine a day. This includes caffeine from coffee, tea, soft drinks, cocoa and chocolate.
A short guide to caffeine contents
Caffeine content in food and beverages varies across brands, depending on caffeine sources and cooking methods. Here's a general guide:
Caffeine source Typical milligrams
of caffeine
Brewed coffee (1 cup) 85
Instant coffee (1 cup) 75
Decaffeinated coffee (1 cup) 3
Caffeinated iced tea (1 cup) 40
Caffeinated hot tea (1 cup) 60
Caffeinated soft drinks (12 ounces) 30 to 60
Semisweet dark chocolate (1 ounce) 20
Valued for its mild stimulating effect
Most people find that caffeine helps them feel more energetic and alert. This is a predictable response, since caffeine stimulates the central nervous system.
The stimulating effect is short-lived, however. Caffeine doesn't accumulate in your bloodstream. After consuming a food or beverage that contains caffeine, you'll excrete the chemical within several hours.
Caffeine also has medical applications. It's an ingredient in some pain relievers, headache medications and products for nasal congestion. Caffeine is also used in a medication that stimulates breathing in premature babies.
Individual responses vary
Observe people as they consume caffeine and you'll see a wide range of responses.
A few people seem immune to the effects of caffeine.
Others feel shaky after one cup of coffee or tea. Or, one chocolate candy bar after dinner may keep them awake past bedtime.
Some people drink several cups of coffee each day -- or consume the same amount of caffeine from other sources -- and eventually develop a tolerance. In this case, the daily dose of caffeine must steadily increase for any stimulant effect at all.
Research supports moderation
Because caffeine is so widely consumed, its health effects have been well researched. The latest studies don't indicate a link between caffeine consumption and higher risks of cancer or cardiovascular diseases. Nutrition guidelines from the American Cancer Society and the American Heart Association don't include directions to restrict caffeine consumption.
However, heavy caffeine consumption may carry risks for pregnant women. According to researchers from the National Institutes of Health, consuming the amount of caffeine contained in five or more cups of coffee a day appears to double the risk of miscarriage. The March of Dimes suggests limiting caffeine intake to less than 300 milligrams per day during pregnancy.
Caffeine also passes into breast milk. Nursing mothers who drink more than two cups of coffee a day or consume an equal amount of caffeine from other sources may find that their babies have trouble sleeping.
Know when you've had too much
The key to enjoying products that contain caffeine is moderation. If you consistently consume more than 280 milligrams of caffeine per day you may experience symptoms such as:
* fast or irregular heartbeats
* feelings of nervousness or anxiety
* irritability
* insomnia
* dizziness
* dehydration
* discomfort with urination
If you try to skip your morning cup of coffee and find that you have a headache, you may be experiencing caffeine withdrawal. This is a sign that you've developed a physical dependence on caffeine. Ask your doctor about cutting down -- especially if you're experiencing any of the symptoms listed above.
Keep in mind that stopping caffeine "cold turkey" may also cause the symptoms listed above. Your doctor may recommend a more gradual reduction.
In addition, keep the following guidelines in mind:
* If you use caffeine to enhance alertness or fight fatigue, do so only occasionally. No chemical is a good substitute for sleep.
* Avoid consuming caffeine for several hours before bedtime.
* Don't use caffeine to "sober up" someone who consumes too much alcohol. Caffeine doesn't counter alcohol's effects.
* If you like the taste of coffee or tea and want to moderate the stimulating effect, drink them with skim milk or switch to decaf varieties.
* If your health history includes irregular heartbeat, ask your doctor how much caffeine -- if any -- you can safely consume.
* If you're being treated for a condition that leads to dehydration or urinary problems, you may need to reduce your intake of caffeine or avoid it altogether. Again, ask your doctor for guidance.
* If you take any medications, have a chronic medical condition or have a thyroid, cardiovascular or anxiety disorder, ask your doctor if caffeine is safe for you.
* Remember that noncaffeinated drinks such as fruit juice and low-fat milk should be part of a healthy diet.
References
"Caffeine Confusion." Nemours Foundation. http://kidshealth.org/kid/stay_healthy/food/caffeine.html (Viewed 11/17/04).
"Dietary Guidelines." American Heart Association. http://www.americanheart.org/presenter.jhtml?identifier=1330 (Viewed 11/17/04).
"Everything You Need to Know About rochures/caffeinebroch.cfm (Viewed 11/17/04).
Klebanoff, M.; Levine, R; DerSimonian, R.; et al. "Maternal Serum Paraxanthine, a Caffeine Metabolite, and the Risk of Spontaneous Abortion." The New England Journal of Medicine. 11/25/99. http://content.nejm.org/cgi/content/abstract/341/22/1639 (Viewed 11/17/04).
© 2004 Optum. All rights reserved.
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