Caffeine–Stoked Energy Drinks Worry Docs

More than 500 new energy drinks launched worldwide this year, and coffee fans are probably too old to understand why.

Energy drinks aren't merely popular with young people. They attract fan mail on their own MySpace pages. They spawn urban legends. They get reviewed by bloggers. And they taste like carbonated cough syrup.

Vying for the dollars of teenagers with promises of weight loss, increased endurance and legal highs, the new products join top–sellers Red Bull, Monster and Rockstar to make up a $3.4 billion–a–year industry that grew by 80 percent last year.

Thirty–one percent of U.S. teenagers say they drink energy drinks, according to Simmons Research. That represents 7.6 million teens, a jump of almost 3 million in three years.

Nutritionists warn that the drinks, laden with caffeine and sugar, can hook kids on an unhealthy jolt–and–crash cycle. The caffeine comes from multiple sources, making it hard to tell how much the drinks contain. Some have B vitamins, which when taken in megadoses can cause rapid heartbeat, and numbness and tingling in the hands and feet.

But the biggest worry is how some teens use the drinks. Some report downing several cans in a row to get a buzz, and a new study found a surprising number of poison–center calls from young people getting sick from too much caffeine.