More than 500 new energy drinks launched worldwide this year. Nowadays they attract fan mail on their own MySpace pages. They spawn urban legends. They get reviewed by bloggers.
They make up a $3.4 billion-a-year industry that grew by 80 percent last year.
Nutritionists warn that the drinks are laden with caffeine and sugar (an average of 7 teaspoons per can). 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. Danger only adds to the appeal, said Bryan Greenberg, a marketing consultant and an assistant professor of marketing at Elizabethtown College. 'Young people need to break away from the bonds of adults and what society thinks is right,' he said.
Rumors have swirled around Red Bull, the first energy drink ever produced, for years. Contrary to hearsay, the ingredient taurine (an amino acid important in making bile to aid digestion) is not made from bull urine, and Mateschitz did not learn about Red Bull from rickshaw drivers in Thailand.
A Brazilian study found college students didn't feel as drunk as they actually were after drinking vodka and Red Bull. Their perception of their coordination and reaction time didn't match objective tests.
'The truth is, we don't know what kind of effects these ingredients can have,' Braganza said of taurine, glucuronolactone and guarana. 'We have to start doing more studies on this.'
The evidence for increased performance is weak, involving tiny studies. A British study of 42 people found Red Bull had no effect on memory, but did improve attention and verbal reasoning.