Caffeinated Energy: Drinks With Dangers

Sandra A. Fryhofer, MD


March 24, 2011

Sandra A. Fryhofer, MD
Clinical Associate Professor of Medicine, Emory University School of Medicine, Atlanta, Georgia; Past President, American College of Physicians, Philadelphia, Pennsylvania

This issue of Staying Well focuses on dangers and risks of caffeinated energy drinks.

A lot of a good thing is not necessarily better. One of those things is caffeine. Let me begin with my own personal caffeine disclaimer: I love my morning cup of coffee. The caffeine really gets me going. But a cup of coffee is one thing. Energy drinks can be quite another.

Caffeine Comparisons

A 6-ounce cup of homemade coffee has about 75-100 mg of caffeine. The brew at some coffeehouses can be a bit stronger with caffeine content as high as 150 mg in 6 ounces, but it is no more than 25 mg caffeine per ounce. Of course, you usually drink coffee hot, so you sip it, slowly, and with enjoyment.[1]

Energy drinks, on the other hand, are usually chugged cold. The caffeine content of energy drinks can be as high as 500 mg per serving. There are also "energy shots" that deliver a caffeine punch of 100-350 mg per ounce, 3-7 times the caffeine in a regular soda. A 12-ounce can of soda contains a total of approximately 35-50 mg of caffeine.[1]

Ingredients Beyond Caffeine

Energy drinks contain more than coffee-bean-derived caffeine and sugars. Hidden caffeine derivatives in the form of guarana, kola nut, yerba mate, and cocoa can also be found on the list of ingredients. Guarana (also known as Paullinia cupana) on a per-gram basis contains anywhere from 40 to 80 mg of caffeine. This means that the caffeine content listed could underestimate the caffeine punch delivered. These drinks often contain taurine, which has been shown to increase blood pressure and heart rate when combined with caffeine.[2]Ginseng is often added and can interfere with warfarin, estrogen, steroids, and digoxin. Other common ingredients include l-carnitine, and yohimbe. In 2008, German, Hong Kong, and Tawain authorities found trace amounts of cocaine in the energy drink Red Bull Cola.[3]

Hazards of Too Much Caffeine

Energy drinks contain too much caffeine. This can cause anxiety, nervousness, sleep problems, elevated blood pressure, and heart palpitations. Although healthy people can tolerate moderate amounts of caffeine, the content in energy drinks exceeds what could be considered moderate. Adverse health consequences of caffeine intoxication include seizures, mania, stroke, and even sudden death.[2,3] Energy drink-related health consequences reported in German studies include liver damage, kidney and respiratory problems, seizures, and agitation, as well as heart rhythm disturbances, heart failure, high blood pressure, and rhabdomyolysis.[3]

Caffeinated Concerns for Kids

A new study in the journal Pediatrics highlights caffeinated energy drink concerns for children with specific medical conditions, including attention-deficit/hyperactivity disorder, eating disorders, diabetes, and cardiac conditions. It also points out concerns about the link between caffeine and reduced bone mineralization.[3]

Caffeine and Alcohol: A Dangerous Combination

An even more hazardous trend, college students are mixing energy drinks with alcohol. The consequences can be dangerous and deadly. Although these students may think that caffeine counteracts the alcohol, it doesn't. You might not get as sleepy, but you're still impaired and you don't know it.[1,5,6] The high caffeine content has a stimulant effect that prevents you from feeling drunk. Judgment, reaction time, and motor skills, however, are still impaired. A recent JAMA report calls this "wide awake drunkenness," and it can lead to bad choices, risky behaviors, and worse.[1]

Billion Dollar Business

But this phenomenon is not limited to college campuses. Non-college going adults are drinking these beverages too. Energy drinks are big business.[5] In 2006, at least $5.4 billion worth was sold in the United States alone.[1] Sales for 2011 are predicted to exceed 9 billion dollars.[3]

Fortunately, the FDA has put the kibosh on premixed alcoholic energy drinks. On November 17, 2010, the FDA warned 4 companies that caffeine added to malt alcohols is an "unsafe food additive." The companies that got warning letters include Charge Beverages Corporations (makers of Core High Gravity®), New Century Brewing Company (maker of Moon shot®), Phusion Products (maker of Four Loko®), and United Brands Company (maker of Joose® and Max®).[7]

Final Thoughts

The FDA limit for caffeine in cola drinks is set at two hundredths of a per cent (0.02%), a max of 71 mg per 12 ounce serving.[1] Scientists and many parents, including me, wonder why this doesn't also to apply to energy drinks. The JAMA report ends with a plea:

"Scientists and health professionals cannot wait for further FDA action; available scientific evidence indicates that action is needed -- now."[1]

Warn your patients; tell your kids and their friends about the dangers of mixing alcohol with energy drinks. I told mine.


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