After downing three or four energy drinks every day for a couple of weeks, Jason Moore started to get severe chest pains. He thought he was having a heart attack or stroke.
But his doctor told him that the chest pain might be caused by the energy drink.
"I don't think they are safe," said Moore, 32, of Ferndale, Mich.
Now, there is research supporting Moore's concerns -- at least for people with heart problems.
If you are taking medication for high blood pressure or heart disease, a new Henry Ford Hospital study suggests you should think twice before slugging down an energy drink.
"The conservative approach, at least in patients with heart disease or cardiovascular disease, is to just avoid these energy drinks until we learn more about them," says James Kalus, senior manager of Patient Care Services at Henry Ford Hospital in Detroit and lead author of the study.
The researchers found that healthy adults who drank two cans a day of a popular energy drink experienced a 10-point increase in their blood pressure and a five- to seven-beat increase in heart rate. The study is published in March in the Annals of Pharmacotherapy.
"With healthy adults, these increases would probably not be a significant increase," said Kalus, who has a doctorate in pharmacy.
But Kalus said it could be harmful to people with heart problems, adding: "You might have undiagnosed cardiovascular disease."
The study builds on several others that have suggested that there could be dangers in using energy drinks.
Researchers at Wake Forest University School of Medicine claim people who mix energy drinks and alcohol are twice as likely to be injured as those who don't. Australian researchers say one can of Red Bull can increase the risk of heart attack or stroke, even in young people.
And authors of a Johns Hopkins study said energy drinks should be regulated because of the levels of caffeine. The Monster energy drink label warns: "Limit 3 cans per day, not recommended for children, pregnant women or people sensitive to caffeine."
Kalus would not release the name of the energy drink he tested in the study because most have similar ingredients. He is not sure which ingredients cause the rise in blood pressure and heart rate.
"That's part of the problem," he said. "These energy drinks have many components. They have multiple vitamins, and caffeine and taurine are present in all of them. It's unclear from our study what specific part has produced the results we saw."
Patrice Radden, a spokeswoman for Red Bull, said the Henry Ford study "does not show an effect which would go beyond that of drinking a cup of coffee. ...
Health authorities across the world have concluded that Red Bull Energy Drink is safe to consume. Red Bull has been on the market for 22 years and last year alone, 4 billion cans and bottles were consumed worldwide."
Heart disease is the leading cause of death for both women and men in the United States. In 2005, 652,091 people died of heart disease (50.5 percent of them women). It made up 27 percent of all U.S. deaths.
Source: Centers for Disease Control and Prevention
WHAT'S IN A DRINK
The energy drink market started about 10 years ago in the United States and has grown into a $6.5-billion-a-year market.
Most energy drinks include caffeine, sugar, a mixture of vitamins, and taurine, a nonessential amino acid derivative.
Amp Energy, for example, contains 71 milligrams of caffeine per 8-ounce serving. Its label says the drink also includes taurine, ginseng and guarana.
SoBe Adrenaline Rush tops that with 76 milligrams of caffeine for the same serving size and includes D-ribose, L-carnitine and taurine in its description of "energizing elements."
Full Throttle contains 72 milligrams of caffeine with carnitine, taurine guarana and ginseng on its list of ingredients.
By comparison, a can of Coke Classic contains 23 milligrams of caffeine.
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