What's in your energy drink?

By Alexandra Sifferlin, TIME.com | 2/6/2013, 8 p.m.
As concerns over the safety of energy drinks continue to grow, a study outlines the recent evidence regarding the content, ...
The amount of caffeine in energy drinks is not currently regulated by the Food and Drug Administration.

As concerns over the safety of energy drinks continue to grow, a study outlines the recent evidence regarding the content, benefits, and risks of the beverages that are popular with adolescents.

The study, published in the journal Pediatrics, reports that more teens are downing energy drinks; in 2003, 16% regularly consumed the drinks, while in 2008, that percentage jumped to 35%.

One study of college student consumption found 50% of students drank at least one to four a month. This year, research documented a jump in energy drink-related emergency room visits and politicians and consumers called upon the Food and Drug Administration (FDA) to look into deaths associated with the drinks.

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What do the beverages contain that could pose a health hazard? Currently, the amount of caffeine added to energy drinks is not regulated by the FDA, so often the amounts listed (if they're listed) are inaccurate.

Studies also don't support all of the claims made by the manufacturers on some of the other ingredients' ability to maintain energy. The study authors broke down the most common ingredients found in energy drinks: caffeine, guarana, taurine, ginseng, sugars and B vitamins and why they might be problematic.

Caffeine

This is the primary ingredient in energy drinks, and its levels can vary widely. Energy drinks do not fall under the same regulatory category as sodas and often have higher levels of the stimulant than indicated.

For comparison, a 6.5-ounce cup of coffee contains 80 to 120 milligrams of caffeine, tea has about 50 mg, and a 12-ounce cola cannot have more than 65 mg. Energy drinks have significantly higher amounts, with the most well-known brands containing anywhere from 154 mg in a 16-ounce Red Bull to 505 mg in a 24-ounce Wired X505.

There is no official recommended limit for the amount of caffeine a person can consume, but excessive caffeine has been linked to a variety of adverse effects such as high blood pressure, premature birth and possibly sudden death.

Guarana

Also known as Brazilian cocoa, guarana is a plant from South America that contains a caffeine compound called guaranine. One gram of guarana is equal to 40 mg of caffeine. But even if it's in energy drinks, it's typically not included in the total caffeine tally.

"In reality, when a drink is said to contain caffeine plus guarana, it contains caffeine plus more caffeine," the authors write. The FDA has not assessed guarana, so its risks and benefits remain unknown.

Sugars

The sugar content in energy drinks ranges from 21 grams to 34 grams per 8 ounces, and can come in the form of sucrose, glucose, or high fructose corn syrup.

"Users who consume two or three energy drinks could be taking in 120 mg to 180 mg of sugar, which is 4 to 6 times the maximum recommended daily intake," the authors write, noting that adolescents who consume energy drinks could be at risk for obesity and dental problems.