Energy drinks have been popular for years, and the market keeps expanding. Some people drink them like they would soda -- during breakfast, lunch, dinner and as snacks. But there is such a thing as too much energy. A study published today in the journal Drug and Alcohol Dependence delivers a stern warning about the possibility of caffeine intoxication from energy drinks.

"The caffeine content of energy drinks varies over a 10-fold range, with some containing the equivalent of 14 cans of Coca-Cola, yet the caffeine amounts are unlabeled and few include warnings about potential health risks of caffeine intoxication," said one of the study's authors, Roland Griffiths of Johns Hopkins Medical Institutions.

A regular 12-ounce cola drink has about 35 milligrams of caffeine. A 6-ounce cup of brewed coffee has 80 to 150 milligrams of caffeine. The Food and Drug Administration imposes limits on how much caffeine food products can contain (71 milligrams for each 12-ounce can). But energy drinks are designated as dietary supplements, not food products. Thus, manufacturers of energy drinks can load their products with caffeine. Moreover, says Chad Reissig, another of the study's authors: "It's notable that over-the-counter caffeine-containing products require warning labels, yet energy drinks do not."

Caffeine intoxication is a recognized clinical syndrome. It is described as nervousness, anxiety, restlessness, insomnia, gastrointestinal upset, tremors, rapid heartbeat, restlessness and pacing. In rare cases, caffeine intoxication can cause death. See this Mayo Clinic report on caffeine side effects and this L.A. Times story on energy drinks that was written by a doctor.

The authors of the study have called for labeling on energy drinks to inform consumers of what they are getting. Advertising for energy drinks is aimed at teens and young adults and promotes the drinks as performance enhancers. Recently, however, some manufacturers have applied a harder edge to their marketing. One product is named Cocaine, and another product, a powdered energy drink sold in a vial, is named Blow. The makers of both products have received warning letters from the FDA about misleading advertising.

But occasional hand-slaps from the FDA are not enough. Besides caffeine intoxication, the use of energy drinks along with alcohol can be dangerous, the Johns Hopkins researchers say. A recent survey found that 27% of college students said they had mixed energy drinks and alcohol at least once a month. There is even some evidence, says Griffiths, that energy drinks may serve as a "gateway" product leading to more serious drug abuse.

- Shari Roan

Photo credit: PR NewsFolo/Rexam

Energy Drinks Need Caffeine Warning, Scientists Say (Update1)

By Jamie McGee

Sept. 24 (Bloomberg) -- Energy beverages can have 10 times the caffeine of soft drinks, or even more, prompting scientists at Johns Hopkins University to recommend that product labels list the content and warn about health risks.

Energy drinks are sold as dietary supplements, and the Food and Drug Administration doesn't limit their caffeine or require warnings. A typical 12-ounce soft drink contains about 35 milligrams of caffeine, while some energy drinks have as much as 500 milligrams, said the researchers in a report published today in the journal Drugs and Alcohol Dependence. Consumers may be unaware of caffeine content and risks, the report said.

``If you are going to use a drug, you should know what it is, what it does and how to use it effectively,'' said study author Roland Griffiths, a professor of behavioral biology at Johns Hopkins in Baltimore, in a phone interview yesterday. ``If you don't label that, you don't know that.''

Caffeine intoxication can lead to nervousness, anxiety, restlessness, insomnia, gastrointestinal upset, tremors, rapid heartbeat and overdose, Griffiths said. He recommended regulation.

One drink-company marketer said the products can be a safer alternative to drug abuse for teens.

``We say, `Do the drink, not the drug,''' said Raymond Herrera, marketing vice president of Redux Beverages LLC, the closely held owner of the Cocaine Energy Drink, in Murrieta, California. ``If you do the drug you are dumb. If you do the drink you are cool.''

The name ``Cocaine'' is used as a marketing technique and the product isn't a gateway to other substances, he said.

Dietary Supplement

If makers sell energy drinks as so-called dietary supplements, they are exempt from submitting safety evaluations to the FDA before the products are marketed, the result of provisions in U.S. law.

``Whether a product goes down the foods approach or the dietary supplement approach is up to the manufacturer, not FDA, as long as they meet the standards as described in the Dietary Supplement Health and Education Act,'' Siobhan Delancey, an FDA spokesman, said in an e-mail.

The FDA has no ``hard limit'' on caffeine in soft drinks regulated as foods, she said. The agency generally regards caffeine to be safe in soft drinks if it makes up 0.02 percent or less of the product, measured by weight. That translates to 71 milligrams in a 12-ounce container, according to the Johns Hopkins study.

Americans spent about $5.4 billion on energy drinks in 2006, an amount growing about 47 percent a year, the report said. The drinks are promoted as performance enhancers and aimed at young people.

Red Bull, Rockstar

The Johns Hopkins researchers, who have spent decades researching the effects of caffeine, said such top-sellers as Red Bull had 80 milligrams of caffeine per drink, compared with 35 milligrams in a Coca-Cola Classic. Rockstar, another top seller, had 160 milligrams and No Fear had 174. Others such as Wired X505 had 505 milligrams per drink, Fixx had 500 and Cocaine Energy Drink had 280. A 6-oz cup of brewed coffee ranges from 77 to 150 milligrams, the report said.

A 16-ounce ``grande'' coffee from Starbucks has 330 milligrams of caffeine, according to the company's Web site. Sports drinks, such as Gatorade and Powerade, don't contain caffeine. Powerade Energy Edge, a product sold in Australia and New Zealand, has 108 milligrams of caffeine per 15.2 ounces, according to its Web site. Each tablet of Maximum Strength NoDoz, sold over the counter, has 200 milligrams of caffeine.

The researchers said high-caffeine drinks can lead to abuse of prescription stimulants such as Ritalin.

Mixers for Alcohol

Mixing alcohol with energy drinks has become popular among college students, and the trend has dangerous consequences, said Mary O'Brien, associate professor of emergency medicine and public health sciences at Wake Forest University School of Medicine in Winston-Salem, North Carolina.

``The behavior of mixing this with alcohol is actively promoted, and the manufacturers and brewers have capitalized on this behavior,'' O'Brien said. ``Caffeine does not belong as an additive in an alcohol product. It's not the same thing as a rum- and-Coke.''

The caffeine wears off before the alcohol and consumers' motor skills are still impaired, O'Brien said.

The article cites a study that surveyed almost 500 college students and found 51 percent reported drinking at least one energy drink in the last month. Almost one-third of these students reported ``weekly jolt and crash episodes'' and 27 percent said they mixed alcohol with energy drinks at least once in the last month, the report said.

To contact the reporter on this story: Jamie McGee in New York at jmcgee8@bloomberg.net.