A. Energy drinks are really soft drinks with caffeine whether it's added or derived from guarana, the seeds of a climbing vine native to South America. The level of caffeine is generally around 80mg per 250ml can, which is around twice what you'd get from a 375 ml can of cola soft drink (which has always contained a small amount of caffeine) and roughly equal to a cup of brewed coffee.
As a parent, you have to ask: do I want my child taking in the sugar or the caffeine? Forget about the herbal ingredients and vitamins which are there in such small amounts they're not significant. I'd have to say "No".
Firstly caffeine is a stimulant but it can also lead to insomnia and stomach upsets. Second do we want our kids to start getting "hooked" (dependent) on caffeine from an early age? Third we don't want them taking in more sugar from drinks.
So tell your kids these three things mean energy drink are not such a good choice.
One good point: Energy drinks are more expensive – hopefully their sheer expense will also deter consumption!