Energy drinks can be dangerous for heart patients - Study

Energy drinks are generally consumed to gain energy and to promote alertness, maintain blood sugar levels, delay fatigue, and prevent dehydration, but a new study has linked the energy drinks to the high blood pressure and cardiovascular attacks and strokes.

In a small study, presented Tuesday at the American Heart Association's Scientific Sessions 2007 in Orlando, Florida, the researchers warned that energy drinks may significantly boost a person’s blood pressure and heart rate.

The study, conducted by Wayne State University researchers, warned those with heart disease or high blood pressure to completely avoid the energy drinks that contain caffeine and taurine, as they can put them at higher risk of heart attacks and strokes by boosting their blood pressure.

To reach their findings, lead researcher James Kalus of Henry Ford Hospital in Detroit and colleagues studied 15 healthy men and women, whose average age was 26, and who didn’t consume any other caffeine beverage for one week.

Researchers first give the healthy volunteers to drink a popular beverage that contained 80 milligrams of caffeine and 1,000 milligrams of taurine, and then measured blood pressure and heart rate before and after drinking two cans of the drink. After consumption of the drink, they measured healthy young adult’s blood pressure, heart rate and electrocardiogram (ECG) at 30 minutes, one hour, two hours, three hours and four hours.

They then conducted an electrocardiogram, which measures the electrical activity of a heartbeat, and found that just two cans of energy drink increased the blood pressure of healthy young adults by five to ten points and heart-rate levels by five to seven beats per minute within four hours of consumption of the energy drink.

“We saw increasing both blood pressure and heart rate in healthy volunteers who were just sitting in a chair watching a movie,” Kalus said. "The increases in heart rate and blood pressure weren't enough for something to happen acutely, but a person on hypertension medication or who has cardiovascular disease may not respond as well."

"While energy drinks increase concentration and wakefulness, people with risk factors for heart disease could have a bad reaction. The subjects in this study were healthy with low blood pressure."

The level of blood pressure, though, didn’t rise to dangerous levels in the group of healthy people studied, but the increase could be considered serious in persons with cardio disease or high blood pressure, suggests the new study, which was funded by Wayne State University Undergraduate Research and Creative Projects Grant.

The researchers declined to disclose which energy drink brand they used in the study, but said each can of the drink in the study contained 80 milligrams of caffeine and 1,000 milligrams of taurine.

Energy drinks are canned or bottled beverages sold in convenience stores, grocery stores, and bars and marketed primarily to people between the ages of 18 and 30 as a stimulant.

Energy drinks commonly include caffeine- a methylxanthine present in tea and coffee, taurine- an amino acid found in protein-rich foods like meat and fish thought to make people alert, herbal stimulant guarana- extracts from the guarana plant, various forms of ginseng, maltodextrin, inositol, carnitine, creatine, glucuronolactone and ginkgo biloba.

Red Bull Energy Drink, Monster Energy Drink, Full Throttle Energy Drink, Amp Energy Drink, XS Energy Drink, Redline Energy Drink, Rock Star Energy Drink and Spark Energy Drink are some popular energy drinks.

Red Bull was created by Dietrich Mateschitz, an Austrian who adapted the energy drink from a Thai beverage called Krating Daeng, a popular drink with rickshaw drivers in Thailand, and was introduced to Europe in 1987 and to the United States in 1997.

Each can of Red Bull energy drink, which is not required by the U.S. health agency FDA to carry any warnings for any of the ingredients, contains nearly 80 mg of caffeine- about the same amount of caffeine as a cup of brewed coffee and twice the caffeine as a cup of tea, 1000 mg of taurine and 600 mg of glucuronolactone, a substance that is naturally found in the body.

The sales of energy drinks in the United States were $3.5 billion in 2005, and they may reach $5 billion this year, up from about $3.5 billion in 2006, said John Sicher, the editor of Beverage Digest.