Popular energy drink ingredient is banned in several countries

Red Bull has been in the news with some parents concerned over its caffeine content.

But there's another ingredient that is raising concern that has caused several countries to ban the drink.

A can of Red Bull contains mostly familiar ingredients: Carbonated water, sugar and caffeine.

But there's another ingredient, a lot less familiar that has sparked some concern.

Each eight-ounce can of Red Bull contains 1,000 milligrams of taurine. Eight ounces of Monster Energy contains the same amount.

But so little is known about the effects of taurine from energy drinks that Weill Cornell Medical Center took a look.

"I think it would be a good idea for somebody to do some more detailed investigations of its cardiovascular effects in particular combinations with caffeine, since it's been a concern," Neil Harrison, director of pharmacology at Cornell University said.

France blocked the sale of Red Bull in that country in 1996. Only this summer did it finally approve its sale with a warning urging moderate consumption.

Similar labeling appears on cans in Canada.

Red Bull is not yet authorized for sale in Denmark and Norway.

"Some of the concerns might be associated with large intake," Harrison said. "Maybe having six or eight cans of Red Bull in a night."

Red Bull's policy is not to speak on camera, so they answered our questions via e-mail.

"Taurine has been shown to help maintain a healthy cardiovascular system," the company said. "Taurine during athletics thus seems reasonable."

Monster Energy's parent company, Hansen Beverage said their technical director, who is a professor of pharmacology at the University of Arizona Medical Center, called.

He said there is no data showing that drinking up to eight grams of taurine a day, which is how many are in four cans of Monster, is dangerous. In fact, he said taurine actually helps when the heart muscle undergoes strenuous exercise.

Sixteen ounce cans of Monster Energy have labels urging drinkers to "consumer moderately. Limit three cans per day." It also says "not recommended for children, pregnant women or people sensitive to caffeine."

Harrison's lab is conducting more studies on taurine. In the meantime, he recommends moderation when consuming any energy drinks, just as you would with coffee.