SHARON KIRKEY, Canwest News Service
Fresh alarms are being raised over "energy drinks," with experts warning of increasing reports of "caffeine intoxication" and single servings containing the caffeine equivalent of 10 cans of Coca-Cola.
Scientists from the Johns Hopkins University School of Medicine in Baltimore are calling for prominent labels for energy drinks listing caffeine doses and warning of potential risks when used alone, or in combination with alcohol. They're also recommending doctors get familiar with signs of caffeine intoxication, withdrawal and dependence in young people who might be using the beverages.
"In children and adolescents who are not habitual caffeine users, vulnerability to caffeine intoxication may be markedly increased due to an absence of pharmacological tolerance," the researchers warn in the journal Drug and Alcohol Dependence.
The team reviewed energy drinks and claims by manufacturers. They found the caffeine content varies 10-fold.
"You can buy a container that says 'energy drink' on it and it might contain 50 milligrams of caffeine - which is about slightly over the amount in a can of
Coca-Cola - or it might contain 500 mg of caffeine, 10 times that and enough to produce overdose symptomatology," said Roland Griffiths, professor in the departments of psychiatry and neuroscience. By comparison, the caffeine content of a six-ounce cup of brewed coffee varies from 77 to 150 mg.
"Many of these products are not labelled with the amount of caffeine. There are no cautionary notes," Griffiths said.
"If you're given a glass to consume of a beverage and you weren't told what it is, and couldn't taste the difference, and it might contain straight vodka and it might contain beer, that's what we're talking about here."
He says recent research suggests that young people who learn to enjoy the caffeine high from energy drinks may move on to prescription stimulants such as Ritalin.
According to their article, annual worldwide energy drink consumption reached 906 million gallons in 2006. Nearly 500 new brands were launched worldwide in 2006 alone.
The National Post reported yesterday that Canadian sales increased 54 per cent, to $277 million in the year ending in August, after a 71-per-cent increase the previous 12 months, according to ACNielsen.
The European Union requires energy drinks carry a "high caffeine content" label.
In Canada, only Red Bull is authorized for sale as a natural health product. Its label says it shouldn't be mixed with alcohol and no more than two cans (500 ml) should be consumed a day. But Health Canada says the safety of other energy drugs "have not yet been evaluated."
Norway restricts the sale of Red Bull to pharmacies; France and Denmark have prohibited its sale altogether. The Medical Society of Prince Edward Island is considering recommending no energy drinks be sold to young people.
Writing in the journal Drug and Alcohol Dependence, the U.S. researchers say energy drinks are aggressively advertised - primarily to young males - with "alluring" names such as Full Throttle, AMP Energy and Cocaine. Ads promote the psychoactive and stimulant effects of the drinks, they say.
"Consumers may falsely believe that 'more is better' and ingest multiple servings."
As an added risk, some drinks are encouraged to be consumed quickly. One drink, Spike Shooter, claims: "The flavour's so good, you'll want to slam the whole can."
With the drinks widely available in dépanneurs and gas stations, researchers say teens and children "inexperienced and less tolerant to the effects of caffeine" may be at an increased risk for caffeine intoxication - a syndrome recognized by the Diagnostic and Statistical Manual of Mental Disorders, psychiatry's official guidebook of mental illnesses.
Symptoms include nervousness, anxiety, restlessness, insomnia, stomach upset, tremors, rapid heart beat and agitation.
"Caffeine in very high doses can produce convulsions and death," Griffiths said. "That rarely occurs. Most people feel very sick. They may vomit, they may get nauseous."
Forty-one cases of caffeine abuse from caffeine-enhanced beverages were reported to a U.S. poison control centre from 2002 to 2004. Another U.S. poison control centre reported nine cases of adverse reactions to the energy drink Redline from January 2004 to March 2006, the Hopkins team found.
Most were male; the youngest was 13.
In a survey last year of 496 undergraduates, 51 per cent reported consuming at least one energy drink in the last month. Of the energy drink users, 29 per cent reported "weekly jolt and crash episodes," 22 per cent reported headaches and 19 per cent reported heart palpitations from drinking energy drinks.
At least four reports of adverse reactions involving energy drinks have been reported to Health Canada. Symptoms included nausea and vomiting and heart irregularities.
The combined use of caffeine and alcohol is "increasing sharply," the researchers say. When mixed with alcohol, people feel less intoxicated, "so they misjudge the extent to which they are impaired," and people may end up consuming more booze, Griffiths said.
"We need to know how much caffeine is in these products."
Researchers are also calling for a cap on the total amount of caffeine "so we don't have a single product that's very likely to overdose someone," Griffiths said.
How the Kicks Rate
Sample of energy drinks and their caffeine content published in Drug and Alcohol Dependence:
Wired X505 (24 ounces): 505 mg of caffeine
Fixx (20 ounces): 500 mg
BooKoo Energy (24 ounces): 360 mg
Redline Power Rush (high concentration energy drink- 2.5 ounces): 350 mg
Redline RTD (8 ounces): 250 mg
No Fear (16 ounces): 174 mg
Monster (16 ounces): 160 mg
Rockstar (16 ounces): 160 mg
Full Throttle (16 ounces): 144
Red Bull (8.3 ounces): 80 mg
Classic soft drinks:
Coca-Cola Classic (12 ounces): 34.5 mg caffeine
Pepsi Cola (12 ounces): 38 mg
Dr. Pepper (12 ounces): 41 mg
Mountain Dew (12 ounces): 54 mg
© The Gazette (Montreal) 2008
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