An average serving of V contains 1000mg of taurine, 600mg of guarana extract and 155mg caffeine. An average serving of Monster contains 2000mg of taurine, 10mg of guarana extract, 405mg of ginseng extract and 160mg caffeine. A 250ml can of Red Bull contains 1000mg of taurine and 80mg of caffeine.
The study, led by Dr Fabian Sanchis-Gomar of the Research Institute of Hospital 12 de Octubre in Madrid, Spain, and published by the Canadian Journal of Cardiology, also warned against consuming the beverages before and during sports, or combining them with alcohol and other drugs.
University of Otago Professor in human nutrition and medicine, Dr Jim Mann, said the combination of sugar and caffeine in energy drinks was not beneficial, though he'd not seen evidence to show ingredients mentioned in the study increased the risk of heart attacks in adolescents. But he warned that it was not only children who should not consume the drinks.
"One of the worst things is the fact they're called energy drinks, which I think implies that they have some benefit, whereas they have none whatsoever, and kids are drinking them like mad."
In New Zealand, energy drinks must contain no more than 320mg per litre of caffeine, including guarana.
Energy drinks must be labelled with the amount of caffeine and an advisory statement saying the product contains caffeine and is not recommended for children, pregnant or lactating women, and individuals sensitive to caffeine.
A spokeswoman from Red Bull said a 250ml can of the drink contained 80mg of caffeine, about the same as a cup of coffee.
"However, in general children should consume less caffeine than adults due to their lower body weight. This is why we do not recommend Red Bull energy drink to children."
Monster said last year that its drinks were not marketed to children.
V's parent company Frucor is a member of the New Zealand Beverage Council. The council's Kerry Tyack said its members did not market energy drinks to children.
