Over the years, caffeine has been the subject of controversy. Many people avoid it like the plague and others swear by it. Researchers have tested its safety and its effect on humans in hopes of settling the debate.  Myths about caffeine have been repeated and passed along until most people believe the information to be factual. Misunderstanding abounds, even among healthcare professionals. 
    One of the widely accepted myths is that caffeine causes hyperactivity in children.
(This is usually combined with the myth that sugar causes hyperactivity as well.) The truth is that children metabolize caffeine faster than adults so pound for pound, children are no more sensitive to caffeine than adults. Studies have shown that moderate consumption of caffeine has no adverse effects on activity levels or attention spans of children.  A recent study showed that adolescents performed better on tests with a little caffeine.  I have often heard moms say their children “bounce off the walls” after a birthday party with cake and caffeinated sodas. Perhaps the excitement of the party itself is more to blame.
    Caffeine has been labeled as “dehydrating” but new information disputes this belief.
Caffeine is a mild diuretic, but beverages that contain caffeine will contribute to hydration. That’s right, you can count that diet soda or your iced tea as part of the eight or nine glasses of “water” you need daily. In people who are accustomed to consuming caffeine, no negative effects on hydration status are observed.
    Another common belief is that caffeine is “addictive.” Moderate caffeine consumption is safe and caffeine should not be classified with addictive substances. If you have ever stopped your caffeine intake abruptly, you probably got a headache. If you want to reduce your caffeine to a more moderate level of about 300 milligrams daily, gradually decrease your intake over several days to avoid the discomfort.
    Women have been told to avoid caffeine because it causes osteoporosis and fibrocystic breast disease. Research has shown that caffeine intake is not a significant risk factor for osteoporosis especially if women have an adequate intake of calcium daily. The American Medical Association’s Council on Scientific Affairs and the National Cancer Institute have published reports stating that there is no association between caffeine intake, fibrocystic breast disease, or any type of cancer. Pregnant women should limit consumption to 250 milligrams daily or the equivalent of one or two 8 ounce cups of coffee.
     What is the caffeine content of common beverages?

• Brewed coffee, 8 ounces, 135 milligrams
• Iced tea, 12 ounces, 10 – 25 milligrams
• Green tea, 8 ounces, 25 – 40 milligrams
• Black tea, 8 ounces, 40 – 70 milligrams
• Coca-Cola classic, 12 ounces, 34 milligrams
• Diet Coke, 12 ounces, 45 milligrams
• Mountain Dew, diet or regular, 12 ounces, 55 milligrams
• Pepsi cola, 12 ounces, 37 milligrams
• Sprite, 12 ounces, 0 milligrams

Caffeine in moderation can increase alertness and is safe. Intakes of greater than 500 milligrams daily can cause nervousness, insomnia, nausea and headaches.