How safe is your energy drink?

HOUSTON But what about the energy drinks that don't contain alcohol? A Houston medical researcher took a look at what's in them.

People are grabbing energy drinks before or after exercising.

UT Houston Medical School Researcher Dr. John Higgins wanted to know what's in energy drinks. He analyzed the ingredients in some of the top energy drinks. His report was published in the November issue of the Mayo Clinic Proceedings.

Here's what he found:

"One of the main substances is caffeine, and caffeine can cause the heart rate to increase and also the blood pressure to increase, and in someone who has a problem with the heart, that may potentially precipitate a heart attack and or a stroke." Higgins said. "And the second major component is sugar, and they are loaded with sugar. They have about 13 teaspoons of sugar or about a quarter of a cup." Medical student and runner Robert McGuffey says that boost is why he likes energy drinks.

"I've been drinking them fairly often," he said. "I guess it started back in college when they started becoming popular."

Dr. Higgins says for healthy people like McGuffey, an occasional energy drink is safe. But he says medical reports have found 10 people have had serious problems that may have been related to the drinks.

"These individuals have consumed between two and eight cans of these energy beverages and ran into problems," Dr. Higgins said. "Some of them have had seizures, and some have even had cardiac arrests."

Dr. Higgins says the caffeine and sugar can affect blood pressure and heart rate. Then Dr. Higgins says he is also worried that some of the herbs in the drinks may combine to increase the effects of the caffeine.

One of the energy drink companies we contacted said, "Most energy drinks actually contain about half the caffeine of a similar size cup of coffeehouse coffee," and "What we need to remember is the importance of consuming all foods and beverages in moderation."

"I read the report and based on it, it doesn't seem like they're dangerous in moderation for healthy people," McGuffey said.

Dr. Higgins recommends that people with health problems check with their doctor first. For healthy people, Dr. Higgins suggests drinking in moderation.

"In a young, healthy person whose been seen by a physician and has been deemed to be in normal perfect health," Dr. Higgins said, "I think in moderation, one energy beverage per day appears to be safe."