STEVE INSKEEP, HOST:
Another thing you may have noticed at the grocery store is the explosion of caffeinated energy drinks. As more and more of these products come onto the market, they're blurring the lines between soft drinks, coffee and juices.
Some are labeled as food; some, as dietary supplements. And as Murray Carpenter reports, consumers often have little guidance on how much caffeine they contain.
MURRAY CARPENTER, BYLINE: At a convenience store in College Park, Maryland, energy drinks are on sale two for one, and people are stocking up. Student Maria Toner says they are essential for studying.
MARIA TONER: I try not to drink them very often, but it's a must right now. I really like NOS; that's my favorite. But they don't have any in here, so Red Bull's my second choice.
CARPENTER: Ever since Red Bull was introduced in the United States in 1997, energy drink sales have grown like wildfire. Coolers are filled with brands like Monster M-80, Rockstar Punched and Spike Shooter. Now, there are even canned coffee and tea drinks boosted with extra caffeine. But beyond the word "energy" on the label, it's hard to tell exactly what an energy drink is.
At the back of this store, researcher Amelia Arria peeks into a cooler full of cans - each with its own, often inscrutable, style of labeling.
AMELIA ARRIA: This is Monster Assault Energy. And this one has 2,500 milligrams of the energy blend, the proprietary energy blend. But the caffeine is not labeled separately. So we don't know how much caffeine is in this.
CARPENTER: Arria is the director of the Center on Young Adult Health and Development, at the University of Maryland School of Public Health. Several years ago, she was surprised to find that about half the students she interviewed for a long-term study used energy drinks. Arria says there's been very little research on them.
ARRIA: We haven't had any qualitative studies to understand what the motives are, what the effects are. This is a totally new area of public health research.
CARPENTER: Last year, she and a colleague wrote a column in the Journal of the American Medical Association, advocating better labeling.
ARRIA: We thought that it would be a good idea for the consumers to actually know how much caffeine they were consuming.
CARPENTER: The American Beverage Association has recently drafted voluntary guidelines for energy drinks, suggesting bottlers label the caffeine quantity; discourage mixing them with alcohol; and note that they are not intended for children, pregnant or nursing women, or people sensitive to caffeine.
But however they are labeled, even regulators are hard-pressed to define energy drinks. Susan Carlson is with FDA's Office of Food Additive Safety.
SUSAN CARLSON: They range all over the place - from products that have probably no caffeine, to products that do have caffeine; and products that have ingredients that may contain caffeine. But there is no regulatory definition for energy drinks, per se.
CARPENTER: Confusing matters further, drinks like Rockstar and Monster are labeled as dietary supplements, while Red Bull is labeled as food. But in both cases, Carlson says FDA has established no regulatory limits for the caffeine.
CARLSON: The only regulation that we have currently for caffeine is the one that is for cola-type beverages.
CARPENTER: That standard limits the caffeine in colas to 200 parts per million - higher than Coke, but lower than Red Bull.
CARLSON: However, FDA always has the right under the law to question a manufacturer's use of an ingredient, and their safe use of an ingredient.
CARPENTER: FDA is concerned about conventional foods being marketed as dietary supplements, and Carlson says the agency is taking public comment on draft guidance for industry.
In October, Canadian regulators went further, placing limits on the caffeine contents in energy drinks. Meanwhile, the energy boom shows no sign of abating. Now, there's this new blend...
(SOUNDBITE OF AD)
UNIDENTIFIED ANNOUNCER: Minute Maid Enhanced, with a natural energy boost. Put good in, get good out.
CARPENTER: That's right - caffeinated fruit juice.
For NPR News, I'm Murray Carpenter.
(SOUNDBITE OF MUSIC)
INSKEEP: And that's "Your Health," for this Monday morning.
(SOUNDBITE OF MUSIC)
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.