The "functional beverage" industry is part of a larger trend known as "nutraceutical foods," which has exploded in part because it occupies a gray area between foods and dietary supplements. Congress, prompted by lobbying from herbal-supplement companies, exempted substances like guarana, kava kava and ma huang from strict regulation by the FDA in 1994. This was despite evidence linking misuse of ma huang to serious medical problems, including heart attacks and death.

"How do you propose to enforce an age limit on caffeine? Given its penetration in our society, it's impossible to keep caffeine away from kids. It's just so ubiquitous in our culture."

If that's the logic, you could easily say that about anything...